Wally s3 e cold_rolling_mills_strip_processing_lines

COLD ROLLING MILLS andSTRIP PROCESSING LINES

Session 3COLD ROLLING MILLS STRIP PROCESSING LINES

SMS metallurgy Conference 2007

Most recent technologies incold rolling to improve productquality

Dr. Hartmut Pawelski

General Manager

Metal Forming and Surface Technology

Dipl.-Ing. Christoph Schwarz

Deputy General Manager

Technical Sales Cold Rolling Mills

Dipl.-Ing. Rüdiger Holz

Execute Vice President

Cold Rolling Mills Division

Dr. Karl Hoen

General Manager Plant Technology

Hot/Cold Rolling Mills Division

SMS Demag AG

Düsseldorf/Hilchenbach, Germany

Most recent technologies in cold rolling to improve product quality

Rüdiger Holz, Dr. Karl Hoen, Dr. Hartmut Pawelski, Christoph Schwarz

In recent years, the steel industry world-

wide achieved remarkable growth rates.

It is not only growing in Asia, here espe-

cially in China and India, but also in

Europe and America. At the same time,

its consolidation is going on and the

steel markets become more and more

global.

In such an environment it is important for

mill owners to meet highest quality re-

quirements and at the same time curb

the production costs.

SMS Demag as system supplier for inte-

grated solutions of rolling mill technology

developed a large number of suitable

systems for supporting mill owners in

these efforts. Examples of effective solu-

tions in cold rolling mills for achieving

high quality requirements and highest

economic efficiency are the following:

▬ Equipment for Edge Drop Control to

achieve a constant strip thickness

across the complete width,

▬ the T-roll® process technology,

▬ an alternative lubrication and clean-

ing concept for an improved strip sur-

face quality and

▬ online measuring systems for the

documentation of product quality and

meeting of narrower tolerances.

Edge Drop Control (EDC®)

Edge Drop describes the undesired

thickness drop in the edge zone of cold

rolled strips. Reason for it is the chang-

ing roll flattening in the transition from

the loaded to the unloaded rolling sec-

tion. Depending on the intended use of

the strip, this area has to be removed.

For this purpose, the strip is trimmed

what will reduce the plant yield.

For avoiding such losses, SMS Demag

developed Edge Drop Control strategies

for reversing cold mills and tandem cold

mills.

For compensating the thickness drop,

the work roll diameter in the strip edge

area has to be reduced. For this pur-

pose, the work roll barrel is tapered by a

special grind at one end. The principle of

the control is now based on shifting the

taper for so far into the strip edge zone

until a specified edge drop value is set.

The operating results of the CSC revers-

ing mill in Taiwan illustrate the difference

between using and not using an Edge

Drop Control for non-grain-oriented

silicon steel. Application of the Edge

Drop Control was able to reduce the

trimming losses by over 20 mm for each

side. This increases the yield for the

common strip width by more than 3 %.

The strategy for a continuously operating

tandem mill is a combination of open-

and closed-loop controls. The drop in

thickness is measured after the first and

the last stand (stand 5). The first mea-

surement is used for controlling the edge

drop in stand 1. At the same time, this

signal is applied for a pilot control of mill

stands 2, 3 and 4. The measurement

after the last stand is introduced to cor-

rect the control command of the pilot

control in mill stands 2, 3 and 4 and that

way the desired edge drop value after

stand 5 is set.

As the operating results show, this strat-

egy is suitable to set a constantly low

value for edge drop over the entire strip

length and thus subsequent trimming

losses are reduced.

T-roll® process technology

For optimizing the cold rolling process

and for an improved product quality it is

indispensable to understand the physical

processes during cold rolling in a better

way.

Therefore SMS Demag developed

T-roll®, a technology package including

new and enhanced physical model ap-

proaches for simulating the cold rolling

process. Beside the complete mechani-

cal and thermal description it is above all

the detailed and realistic description of

the tribological processes which open up

new options for process optimization.

The accuracy of the model approaches

becomes apparent in the high coinci-

dence between measurement and simu-

lation. Examples are the accurate simu-

lation of rolling force and strip lead as

well as the transfer of the roll surface

roughness onto the strip surface.

As examples for the efficiency of T-roll®,

the optimization of a single-stand revers-

ing mill for the production of grain-orient-

ed silicon steel shall be mentioned. In

this project, the lubricant and the appli-

cation of lubricant could be improved in a

well-aimed way by the new way of con-

sidering the tribology in the roll gap. This

enabled a clearly higher rolling speed

and thus a clear improvement of the

plant's output capacity.

A second example is the avoiding of

form waves in cold rolling of brass in a

two-stand tandem mill. It was only

through the analysis of the problem by

means of the T-roll® technological pack-

age and a test setup in the laboratory

based thereon that it was demonstrated

that the form waves exclusively occur

through insufficient lubrication condi-

tions. By improving the lubricant and di-

rect application of an additive in the first

passes the form waves were avoided.

Lubrication and cleaning concept

As a new lubrication and cleaning con-

cept, SMS Demag developed a com-

bination of least quantity lubrication and

the utilization of liquid nitrogen. In skin-

passing, this concept decisively im-

proves the strip surfaces and at the

same time curbs the operating costs.

When using the least quantity lubrication

in the skin-pass stand entry, the lubricant

volume is precisely applied, which is re-

quired for reducing the friction in the roll

gap. This reduces the rolling force and

improves flatness at simultaneously us-

ing a minimum quantity of lubricant. The

liquid nitrogen in the exit covers both the

strip surface and the roll surface. This

method has the following advantages:

▬ clean and dry strip surfaces and thus

clearly lower susceptibility to rust,

▬ clearly reduced efforts in the down-

stream cleaning steps for cleaning

the strip surface and

▬ prolonged work roll service lives.

For assessment of the strip surface qual-

ity, the same material was skin-passed

under different operating conditions. In

the pass with emulsion, clear impres-

sions of the lubricant could be found.

They make the surfaces appear less

bright. The roll abrasion in dry skin-pas-

sing has a similar effect on the surface

quality. Compared to that, the surfaces

are clearly more uniform and thus

brighter when using liquid nitrogen in the

entry or in the entry and exit.

Moreover the operating experience

showed that the use of nitrogen more

than doubled the work roll service lives.

This and the lower refinishing effort on

the strips led at our cooperation partner

C. D. Wälzholz to cutting the process

costs for skin-passing by ca. 20 %.

The most recent reference for this con-

cept is the new inline skin-pass mill

stand for the continuous annealing line

of ThyssenKrupp Steel in Dortmund,

Germany.

Online measuring systems

Efficient production on a high quality lev-

el today requires complete documenta-

tion of the main quality parameters. Only

that way it is possible to demonstrate

quality towards the customer and at the

same time efficiently track down causes

for quality problems in the process line

and to remedy them.

Our new "Rotary Inspect" inline inspec-

tion line sets the record here for safety

and ergonomics in the manual assess-

ment of strip top and bottom sides.

Our patented roughness control system

enables controlling the strip roughness

over the entire length to a constant value

and to perform the roll change only when

it is really needed. For roughness mea-

surement, the SORM 3 plus measuring

system of our cooperation partner EMG

is used.

The SMS Demag flatness measuring

roll is the ideal solution for precise and

reliable measurement of strip flatness.

The closed surface of the roll avoids

marks on the strip and can be coated

specifically for each application. The roll

allows simple installation of the sen-

sors which can even be performed on

site. The sensors can be arranged flexi-

bly regarding their distances in accor-

dance with the current and future re-

quirements of the profile and flatness

control system.

Ten references within a short time

demonstrate our customers' high

acceptance of this measuring system.

1SMS metallurgy Conference 2007

Most recent technologies in cold rolling

SMS Demag solutions for improved product quality

Edge DropControl

T-roll® process

technology

Lubricationand cleaningconcepts

Online measure-ment systems

Constant strip thicknessup to the edge

EDC

Closer tolerances andbetter documentation

Higher yield and improvedproduct quality

T-roll®

process technology

Lubrication andcleaning concepts

Online measurementsystems

A new approach forperfect surface quality



EDC®Edge Drop Control � constant strip thickness

up to the edge

Edge DropControl

T-roll® process

technology





Principle of the Edge Drop Control

Edge DropControl

T-roll® process

technology



Stripthickness

Principle of work

roll shifting for

Edge Drop Control

Strip width

with EDC

without EDC

Reduced

Edge Drop

Influence of EDC on the

strip edge

transverse

material flow


Results of Edge Drop Control in a single-stand

reversing mill


Edge DropControl

T-roll® process

technology



Material: Non grain-oriented silicon steel

0 20 40 60 80 100 120-2.5

-2

-1.5

-1

-0.5

0

0.5

Distance from strip edge

Thicknessdeviation[%]

Edge Drop measurement

Hot strip

After last pass

with EDC

without EDC

Yield increased by approx. 3 % due to by reduced trimming losses►►



Edge Drop Control strategy for a continuous

tandem cold mill

Edge DropControl

T-roll® process

technology



AW

PositionAW

Position

AW

Position

S1 S2 S3 S4 S5

EDC

Vorsteuerung

EDC Regelung

G2;G3;G4

AddRef

AddRef

Ref Ref Ref

AW

Position

Ref

AddRef

EDC Regelung

G1

Act

AW

Position

WR

shiftingAW

Position

WR

shifting

AW

Position

WR

shifting

measured

edge drop

edge drop

references

EDC

feed forward control

EDC feedback control

G2;G3;G4

AddRef

AddRef

Ref Ref RefRef Ref Ref

AW

Position

WR

shifting

Ref

AddRef

EDC feedback control

G1

Act

Model

parameter

measured

edge drop

EDC feedback control for S1 EDC feed forward control and feedback control of S2, S3, S4



Results of closed loop Edge Drop Control in a

tandem cold mill

Edge DropControl

T-roll® process

technology



position(mm)

Strip length [m]

G1 G2 G3 G4

0 100 200 300 400 500 600 700 800 900 1000 1100 12000

20

40

60

80

100EDC-Position (measured)

Strip length [m]

0 100 200 300 400 500 600 700 800 900 1000 1100 1200-10

0

20

40

60

80

Edge drop (measured)

Edgedrop[μm]

Edge drop measured

EDC workroll shifting position

Strip length [m]

Edgedrop(μm)

after G1 after G5

Reference value:

after stand 1 20 μm

after stand 5 10 μm

with EDC

Edge drop reduction constant over total strip length►►




Edge DropControl

T-roll® process

technology



Technology package for the simulation of the cold rolling

processes with advanced models for

▬ mechanical

▬ thermal and

▬ tribological processes

Applications:

▬ thermal and tribological processes

▬ Analysis and optimization of

lubrication and cooling conditions

▬ Selection of adequate lubricants

▬ Development of new rolling strategies

▬ Calculation of pass schedules for

new steel grades

▬ Pre-calculation of strip surface

roughness

More profit due to higher yield and improved product quality►►




Edge DropControl

T-roll® process

technology



High capability of new approaches

0

0.5

1

1.5

2

2.5

3

0.0 0.5 1.0 1.5 2.0 2.5Elongation in %

Roughingofstrip,Rainμm

Measured, top

Measured, bottom

Tribological model

Tribologisches Modell

Rolling Speed [m/min]

Walzkraft [MN]

Walzgeschwindigkeit [m/min]



Walzkraft [MN]

Tribological model


Roll force [MN]

Roll speed [m/min]


tribological model

Voreilung [%]



tribological model



Voreilung [%]

Walzgeschwindigkeit [m/min]Rolling Speed [m/min]

tribological model

Voreilung [%]



tribological model


Tribological model

forward slip [%]

Roll speed [m/min]

▬ High forecast accuracy for

� improved processing and

� higher plant utilization



Cold rolling of high-grain-oriented silicon steel

Edge DropControl

T-roll® process

technology



before modernization

after modernization900 m/min = max. motor speed

5 pass HGO

Share of production approx. 30 %

Max.rollingspeed

[m/min]

900

600

300

0pass 1 pass 2 pass 3 pass 4 pass 5

Increase of maximum speed by tribological optimization►►



Cold rolling of brass on a tandem cold mill:

elimination of waves

Edge DropControl

T-roll® process

technology



SMS Demag solutions:

▬ Optimization of lubricant

▬ Low quantity lubrication for first passes

►►



Combination of low-quantity lubrication and

liquid nitrogen

Edge DropControl

T-roll® process

technology



Low quantity lubrication Liquid nitrogen

▬ Substantial reduction of

lubrication quantities

▬ Reduction of friction in the

roll gap

� lower rolling force

� improved strip flatness

▬ Improvement of strip surface quality

▬ Better cleaning effect on work rolls

▬ Longer service life of work rolls

Benefits:In cooperation with:

C.D. Wälzholz

►►



Skin-pass rolling with liquid nitrogen

Edge DropControl

T-roll® process

technology



Valuation of strip surface quality after skin-pass rollingTarget: Ra = 1,0 � 1,8 μm; shining surface

Liquid nitrogen,

entry

Liquid nitrogen,

entry and exit

Emulsion, entry(height profile: ± 0,8 μm)

100 μm

lubricant impressed

dry

Abrasion of rolls

Improved surface quality

Considerably improved strip surface quality►►



Skin-pass rolling with liquid nitrogen

Edge DropControl

T-roll® process

technology



after coil No. 1: 1.4 μm

after coil No. 4: <1.0 μm

Roughness of new work roll: 3 � 3.3 μm



Coil No.

Dry (2004-05-03)

3.0

10

1 2 3 4 50.0

0.5

1.0

1.5

2.0

2.53.0

Roughness of new work roll: 3 � 3.3 μm

Coil No.

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1 2 3 4 5 6 7 8 9 10

Liquid nitrogen (exit)

Service life of work rolls increased by more than 100 %

Skin-pass process costs reduced by 20 %

►►



Recent reference:

ThyssenKrupp Steel, Germany

New inline skin-pass mill for continuous annealing line

Edge DropControl

T-roll® process

technology



Main technical data:

Strip thickness: 0.4 to 2.3 mm

Strip width:: 600 to 1,720 mm

Roll speed range: 0 to 412 m/min

Annual capacity: 780,000 t

Year of commissioning: 2007

Inline-skin pass

Technical features:

▬ Newly developed low-quantity lubrication

system and roll-strip cleaning with liquid nitrogen

▬ SMS Demag shapemeter roll

▬ X-Pact® � electric and automation systems


►►


Online measurement systems to improve product quality

and plant utilization

Edge Drop

Control

T-roll® process

technology

Lubrication

and cleaning

concepts

Online measure-

ment systemsSMS Demag flatness measurement roll

Inline inspection line

�Rotary-Inspect�SORM roughness

measurement

with control system

Advantages:

▬ Continuous monitoring and documentation of quality parameters

▬ Close tolerances by means of integration in closed loops

In cooperation with:


►►


SMS Demag flatness measuring roll in new design

Edge Drop

Control

T-roll® process

technology

Lubrication

and cleaning

concepts

Online measure-

ment systems

Advantages:

▬ Easy sensor installation even at site

▬ Applicable at high temperatures e.g. production of Si-steel grades

▬ Individual arrangement of sensors

▬ Closed surface

▬ Application-based coating

References in 18 months:

7 plants with a total of 10

shapemeter rolls

Modernization concept of thefour-stand tandem cold rolling mill,BILSTEIN GmbH & Co. KG

Dipl.-Ing. Detlef Böttner


Sales Cold Rolling Mills Electrical and Automation Systems

Dipl.-Ing. Falk Töpfer

General Manager


Dipl.-Ing. Arnulf Wurm

Senior Project Manager


SMS Demag AG

Hilchenbach, Germany

Modernization concept of the four stand tandem cold mill,

BILSTEIN GmbH & Co. KG

Detlef Böttner, Falk Töpfer, Arnulf Wurm

Ever increasing requirements on the cold

strip qualities and the continuously grow-

ing material and variant diversity more

and more force rolling mill owners to

keep their plants on the most recent

technological level or to get them there.

Due to the concurrently very high de-

mand volume and thus the plant utiliza-

tion in recent years, they had to face

particular challenges.

SMS Demag took up these customer

problems and elaborated and constantly

developed special concepts in recent

years to cope with them. This is one of

the reasons why the company BILSTEIN

with their registered office in Hagen,

Germany, tasked SMS Demag with the

extensive modernization of their four-

stand tandem cold mill.

BILSTEIN is processing a diversified ma-

terial and product mix starting from the

standard grades over case-hardening

and special grades up to micro-alloyed

high-strength steels. The tandem mill is

the central key plant for the complete

production at BILSTEIN and in some

cases also for their subsidiary com-

panies. Therefore a consistent and reli-

able modernization concept was even

more significant for taking the decision to

award the contract.

The rolling mill was supplied in 1969 by

SMS Demag and was during the years

upgraded and modernized several times.

This mill produces every year 400,000 t

of cold strip of width from 320 to 670 mm

and thicknesses from 7.5 to 0.3 mm. The

input stock is produced by slitting hot

strip normally into two to three stripes.

Therefore the input stock has different

wedge profiles what is a particular chal-

lenge for the sequences in cold rolling.

The modernization is related to a large

number of objectives of which the follow-

ing are the most important ones:

▬ Improvement of the plant availability

▬ Increase of the production volume by

60,000 t/year

▬ Improvement of the product quality

▬ Increase of the degree of automation

A particular requirement which made the

matter more complicated is that due to

the above mentioned plant utilization the

proper revamp times could only be taken

during regular shutdowns. The total time

available for this is three shutdown peri-

ods of altogether five weeks. After each

modification period, production has to be

run up to the set point volume according

to agreed run-up curves as fast as possi-

ble. In the process, the comprehensive

product mix of wedge-shaped hot strip

has to be considered and the currently

applicable safety standards have to be

observed.

For various reasons, SMS Demag won

the contract for this modernization.

SMS Demag has wide experience in

large and complex modernizations and

was also in this case able to present a

coherent overall concept. The "All from a

single source" supply, i. e. the symbiosis

of mechanics, hydraulics, electrics and

automation as well as development and

technology from one single supplier cre-

ates the optimal conditions for modern-

ization which were critical in terms of

technology and time. Essential mechani-

cal components as e. g. the hydraulic

adjustment cylinders and valve stands

are produced in the SMS Demag work-

shop and carefully tested before deliv-

ery. Moreover, the extensive actions ac-

companying the order are performed for

safeguarding the short modification

phases. Among these are careful site in-

vestigation, early setup of a "listening

mode", a state-of-the-art integration test,

the early operator training on the simu-

lated plant up to a sophisticated change-

over concept between the old and the

new control system.

For achieving the modernization objec-

tives, many components are replaced by

new and more recent ones or additional-

ly integrated into the rolling mill.

For increasing and stabilizing the strip

back tension in the first stand, an addi-

tional strip pinch roll unit will be installed

in the entry guide. It is hydraulically

approached, the additional strip tension

is applied by means of electrically actu-

ated rolls. That way it operates similar to

a bridle roll unit but compared to that it

bears the advantage that it can still be

used for large entry thicknesses.

All mill stands will be equipped with hy-

draulic adjustment cylinders. That way it

is not only possible to increase the rol-

ling force by 30 % in each mill stand but

for the first time it is possible to measure

the precise positions of the cylinders.

This is the prerequisite for converting the

strip thickness control from the currently

used roll gap control to a quick volume

flow control.

Moreover, the rolling speeds of all mill

stands are increased and optimized with

regard to one another. For this purpose,

among other things new gearwheel sets

will be installed. For minimizing the re-

maining quantity of residual oil on the

strip, the patented SMS Demag Dry Strip

System (DSS) will be installed down-

stream of the last mill stand.

The coiling tension will in a similar way

as on the entry side be separated by a

new approachable bridle roll unit from

the exit tension of the last stand. When

the bottom roll of this unit is not ap-

proached, it behaves like a "normal" de-

flector roll, i. e. also this bridle roll unit

can, as the strip pinch roll unit on the

entry side, be started up step by step

without any risk. Various other mechani-

cal extensions supplement the modern-

ization. Among these are in particular:

▬ Various improvements for guiding

and threading the strip

▬ Improvements for calibrating the roll

assemblies

▬ Installation of work roll bending sys-

tems at all stands

▬ New hydraulic valve stands for all

mill stand functions

▬ Installation of devices for measuring

strip position, strip tension and strip

speed at different positions.

The existing electrical and automation

systems will to a large degree be re-

placed by new systems. Interfaces are

created with the remaining components

and systems. All main drives will be re-

placed. For the mill stands, advanced

synchronous motors in medium voltage

technology will be used. Compared to

the asynchronous motors, they provide a

higher operating efficiency at a simulta-

neously smaller moment of inertia which

leads to improved control dynamics.

State-of-the-art multi-drive converters

with a direct current intermediate circuit

supply the medium-voltage motors of the

mill stands as well as the low-voltage

motors of the strip drives for the reels,

pinch roll units and bridle rolls. This reac-

tive power-free drive constellation both

minimizes possible energy losses and

negative effects on the feeding network.

The plant will for the first time be operat-

ed from a newly erected main control

pulpit. Except new operator stations and

an HMI system which can also be ac-

cessed from all local stations, strip edge

detection and camera systems will be in-

stalled at different locations. The latter

are provided for visual monitoring of the

partly automated threading process by

the operator. This is particularly required

when threading the wedge-shape slit

strip.

The automation system will be complete-

ly replaced. In the process, all Level 1

functions from the sequence processes

up to the technological controls are all

implemented on a uniform hardware and

software platform.

In particular for safeguarding the in-

creased requirements on the automation

system, faster coil sequence times and

an improvement of the strip quality at the

head-end, for the first time a Level 2 sys-

tem will be used on this mill. Above the

required interfaces and various report

functions, this system makes available a

model-based setup value calculation be-

fore start of rolling. For this purpose,

SMS Demag uses the complete imaging

of the rolling processes through self-

adapting physical models.

For safeguarding the required run-up

curves after the respective short modifi-

cation phases, SMS Demag uses a con-

cept of several parallel actions. First the

current status is detected by means of

detailed examinations and used as the

basis of the following modifications.

Among these are e. g. detection and

localization of the mechanical and elec-

trical components, functional and pro-

cess-technological aspects as well as

the plant operation.

By documentation of this site investiga-

tion, the engineering could start. On site

almost simultaneously the preparation of

the interfaces is started for the systems

required in the individual modification

phases which are continued to be oper-

ated. Moreover, a "listening mode" is es-

tablished. For this purpose, so-called

process IO servers are installed step by

step which enable forwarding each sig-

nal from or to the process to the existing

control (maintaining the existing status)

but also making available these signals

in a global memory for the later new con-

trol systems. That way the new system

has knowledge of the current process

events at a very early stage. This result-

ing process data basis will be integrated

in the engineering and the pre-commis-

sioning of the new system. That way for

example the mathematical models can

already at that time automatically adapt

to the material to be rolled and the exist-

ing plant.

In a next step, the complete new auto-

mation system will be set up in the

SMS Demag workshop. In parallel, the

rolling mill will be simulated in every de-

tail in real time. Here not only the rolling

process itself is simulated but also all

movements and all interfaces with the

automation system. By means of this

"integration test", already beforehand a

pre-commissioning, complete functional

and production tests are performed. This

comprehensive simulation is also used

for an intensive operator training. Only

that way it is possible to achieve the

short run-up phases.

Now the previously installed listening

mode is expanded in a modification

phase and the following optimization

phase to the effect that new functions or

controls can be added in, tested and op-

timized either completely or also partly.

For this purpose the old and the new

open- and closed-loop systems are oper-

ated in parallel. That way the original

condition can quickly be re-established

by digital adding-in. It is only after all

new functions were sufficiently verified

and optimized that the "old" components

will be dismantled and the final new en-

hanced condition is established.

This modernization concept provides

both the plant operator company

BILSTEIN and the contractor

SMS Demag with the sufficient safety for

a smooth sequence of the modification

as well as the certainty that the modifica-

tion objectives are really achieved within

the defined time frame.


Modernization concept of the four-stand tandem cold mill

BILSTEIN GmbH & Co. KG, Hagen-Hohenlimburg

employees: 600

dispatch volume: 400,000 t/year

▬ cold-rolled steel strip

▬ cold-rolled steel sheet

▬ construction steel

▬ case hardening steel

▬ electrical steel

▬ spring steel

▬ special purpose steel

▬ enameling steel strip

The customer and their products

Introduction

Modernization

objectives

Modernization

items

Modernization

concept


Four-stand tandem cold rolling mill

of BILSTEIN GmbH & Co. KG, Germany

Main mill data

▬ four-stand batch tandem cold mill

▬ Supplier: DEMAG, 1969

▬ Rolling speed: max. 745 m/min

▬ Rolling force: max 6,000 kN per stand


Introduction

Modernization

objectives

Modernization

items

Modernization

concept


Four-stand tandem cold rolling mill

of BILSTEIN GmbH & Co. KG, Germany

Material data

▬ Strip width: 320 to 670 mm

▬ Strip thickness: 7.5 to 0.3 mm

▬ Annual production : 420,000 t

Others

▬ Several modernizations over the years

▬ Four operators, all �on site�

▬ Low automation grade of mill sequences


Introduction

Modernization

objectives

Modernization

items

Modernization

concept



Targets of the modernization

General targets

▬ Increase of mill availability

▬ Increase of production rate by 60,000 t/y

▬ Improvement of product quality

▬ Higher degree of automation

Special requirements

▬ Rolling and threading of wedge-type strips

▬ Extensive product-mix

▬ Change to operating with only three operators

▬ Only the regular mill downtimes can be used (in total five weeks)

▬ High priority in safe and steep run-up after each modernization

step

Introduction

Modernization

objectives

Modernization

items

Modernization

concept



Reasons for placing the order with SMS Demag

▬ Experiences with

comprehensive modernizations

▬ Convincing overall

modernization concept

▬ Supply from one single

source

▬ Manufacture at SMS Demag

workshop

▬ Advanced integration test

▬ Operator training in advance

▬ Switch-over

concept

Introduction

Modernization

objectives

Modernization

items

Modernization

concept



Modernization of mechanical equipment

Entry-side pinch roll unit

▬ improve the strip tension behavior

▬ increase the strip tension

Advantages

▬ independent of the strip thickness

▬ deflector roll mode possible




Hydraulic screw down cylinders for all stands

▬ rolling force increase from 6,000 kN to 8,000 kN

▬ high resolution position measurement

Advantages

▬ higher reduction

▬ change from roll gap to position control mode




New gear sets respect. shifting gear sets between the stands

▬ increase the rolling speeds; from 745 to 1,000 m/min at last stand




Dry Strip System after last stand

▬ increase the removal of the emulsion on the strip surface

Advantages

▬ reduced noise level

▬ best dryness of the strip surface




Exit-side swiveling bridle S-roll set

▬ improve the strip tension behavior

▬ increase the strip tension

Advantages

▬ deflector roll mode possible



New synchronous motors for mill stands and tension reel

▬ increase the rolling speed of each stand

Advantages

▬ high efficiency

▬ low inertia, i. e. high dynamic behavior

Modernization of electrical equipment

Introduction

Modernization

objectives

Modernization

items

Modernization

concept




New multi-drive converter systems

▬ IEGT converters for MV mill drives

▬ IGBT converters for LV drives

Advantages

▬ low energy losses, low power feed-in

▬ high dynamic performance

Introduction

Modernization

objectives

Modernization

items

Modernization

concept




New pulpit, operator panels and HMI system

▬ full HMI access at all operator panels

▬ industrial TV system and strip-edge monitoring systems

Introduction

Modernization

objectives

Modernization

items

Modernization

concept




New Pulpit, Operator Panels and HMI-System

� full HMI access at all operator panels

� industrial TV system and strip edge monitoring systems

Introduction

Modernization

objectives

Modernization

items

Modernization

conceptNew Level 1 automation system

▬ additional measurement devices for strip speed and tension

▬ position sensors of screw down cylinders, vibration monitoring

Advantages▬ switch-over from roll gap control to position control

▬ introducing fast volume control mode

▬ one uniform system platform

G3 G2 G1 G0

HGC

Decoupling Net

Speed and

Torque ControlSpeed

Control

Speed and

Torque ControlSpeed

Control

Speed

Control

Speed

Control

Thickness

Control

HGCHGCHGC

Tension

Control

Thickness

Control

Thickness

Control

Thickness

Control

Tension

Control

Tension

Control

Tension

Control



High-accuracy Level-2 setup system

▬ physical-based models

▬ short-term and long-term self-adapting models

Advantages▬ reduction of off-gages/off-flatness length

▬ fast learning behavior

▬ flexible adaptation to new materials

Introduction

Modernizationobjectives

Modernization

items

Modernization

concept


Mill limits andconfiguration

Rolling force

model

Flatness

model

Temperature

modelTribological

Model

Material

model



High accuracy of SMS Demag Level-2 process models(Example: Single-stand reversing mill for silicon steel)

thickness deviation at head end

[%]

frequency[%]

1,514

strips

force deviation at head end

[relative, kN]

frequency[%]

1,525

strips

0

5

10

15

20

25

30

20001,6001,2008004000-400-800-1,200-1,600

77 % within 0 % to + 3 %

Introduction

Modernization

objectives

Modernization

items

Modernization

concept0

5

10

15

20

25

30

35

40

45

1086420-2-4-6-8



Overall modernization concept:

Engineering, test and interfaces preparation in parallel

Site

investigation

Preparation of interfaces/

listening modeInstallation

Switch-

over

Engineering Plug &

Work test

Stepwise

time

Introduction

Modernization

objectives

Modernization

items

Modernization

concept


Site

investigation



Switch-

over

EngineeringPlug &

Work test

Stepwise


Site investigations

▬ hardware and layout

piping, routing, locations, etc.

▬ functional technology

signals, interfaces, etc.

▬ process sequences and mill operation

standard operation procedure

▬ process technology

pass schedules, emulsions, etc.

Site investigation

Introduction

Modernization

objectives

Modernization

items

Modernization

concept



Hot run tests and �shadow mode�

▬ stepwise function and production test

with mechanic and media systems

▬ test of sequences, test of dynamic behavior

▬ always possible to switch back to old controls

(�shadow mode�)

Old New

~~

M

~

PPS /L3

Processmodels /L2

Processcontrol /L1

RIOsPIOS

ProcessModels /L2

Processcontrol /L1

PIOS (Process IO Server) =

�electronic terminals�

InstallationSwitch-

over

Introduction

Modernization

objectives

Modernization

items

Modernization

concept

Site

investigation



Switch-

over

EngineeringPlug &

Work test

Stepwise



Typical run-up curve for a modernization

with production increase

0

10

20

30

40

50

60

70

80

90

100

110

120

130

1 3 5 7 9

11

13

15

17

19

21

23

25

27

29

31

33

35

37

39

Weeks

Productionperweek[%] Downtime

Introduction

Modernization

objectives

Modernization

items

Modernization

concept

Cold rolling of stainless steelusing continuous high-perfor-mance tandem mills

Dipl.-Ing. Rainer Effertz


Filtration Systems/Roll Coolant Systems

Dipl.-Ing. Rüdiger Holz

Executive Vice President

Cold Rolling Mills Division

Dipl.-Ing. Ralf Matzka

General Manager

Technical Sales Cold Rolling Mills and

Stainless Steel Lines

Dipl.-Ing. Thorsten Bode

Manager

Metal Forming Technology

SMS Demag AG

Düsseldorf/Hilchenbach, Germany

Cold rolling of stainless steel using continuous high-performance

tandem mills

Ralf Matzka, Thorsten Bode, Rainer Effertz, Rüdiger Holz

The market for cold-rolled stainless steel

strip is characterized by continuous

growth. The ever higher growth rates of

cold rolled products require ever higher

capacities of the process lines and

rolling mills. Further the market requires

reasonable prices for these products,

with the optimization potential mainly be-

ing the cost of production.

As long ago as 1969, the Nisshin Steel

company in Japan attempted to satisfy

this market requirement by installing a

then highly productive multi-stand tan-

dem mill for the production of cold-rolled

stainless steel. Another high-perfor-

mance mill, supplied by SMS Demag,

went in operation in 1999 at AK Steel in

the United States, rolling both stainless

steel and carbon steel grades. The new

plant concept developed by SMS Demag

for stainless-steel tandem mills consists

of several rolling mills in a tandem ar-

rangement, with extremely slender and

therefore horizontally supported work

rolls.

Setting up a continuous rolling mill for

the production of stainless steel strip is a

cost-effective option where a cold-rolling

stage with a capacity of more than

400,000 t/year is to be implemented.

This plant concept requires the lowest

cost of conversion due to the as com-

pared to conventional stainless steel

rolling on reversing rolling mills higher

yield, less manpower and the lower

specific investment cost. The new plant

concept using rolling oil makes it pos-

sible to produce surface finishes that

bear comparison with cold rolled strip

produced in 20-roll mills. As compared

with the well-known fully integrated lines

for the production of stainless steel strip

(integrated rolling, annealing and pickling

lines), the concept of a continuous tan-

dem mill has a much higher flexibility.

The differences between the continuous

tandem mills set up so far for the produc-

tion of cold-rolled stainless steel strip are

as follows: The first mill in Japan was set

up as a semi-continuous line and has no

continuous exit. The mill stands are of

20-roll type and accordingly have long

roll-changing times of the backing ele-

ments and intermediate rolls. Another

critical item in this mill stand design is

the relatively poor accessibility in case of

strip breaks. The continuous tandem mill

at AK Steel was designed for the mass

production of carbon steels and austenit-

ic as well as ferritic stainless steels. The

rolling mills are of four-high (mill stands 1

to 3) and six-high type (mill stands 4

and 5. The roll diameters were chosen to

suit stability requirements and the

torques needed to drive the work rolls,

they warrant a simple mill stand design

with associated high service life and

availability. Thanks to the application of

a special cooling lubricant and the use of

the required roll roughness it has also

been possible to satisfy customers' sur-

face finish demands. The new

SMS Demag concept for a continuous

rolling mill for stainless steel strip is

based on the quality requirements of a

specialized cold strip production using

20-roll mills. To achieve the necessary

overall reduction, a very slender work roll

was chosen which via laterally arranged

intermediate rolls is supported on both

sides by two rows of backup bearings.

The mill stand design encompasses a

six-roll mill with backup, intermediate

and work rolls. The intermediate rolls are

axially shifted and equipped with a roll

bending facility. The tandem rolling mill

is equipped for fully continuous oper-

ation, i. e., on the entry side a welder

and strip accumulator to bridge the non-

productive entry time are arranged,

whereas on the exit side coils are

changed on the fly. The above requires

the exit tension in the last mill stand to

be maintained with the help of a pinch-

roll mill stand and the continuous supply

of paper through the use of carousel-

type paper winders and automatic

threading devices.

In the production of cold-rolled stainless

steel strip in continuous tandem mills,

the following special technical items

need to be considered:

▬ The large variety of the products to

be rolled in terms of their dimenions

and mechanical properties requires

an adapted mill stand design.

▬ The benefit of the high yield can be

achieved only in continuous opera-

tion.

▬ The excellent surface finishes can be

achieved only through the use of

suitable cooling and lubrication sys-

tems as well as an effective surface

inspection.

▬ The benefit of the lower specific in-

vestment cost becomes fully effective

especially in a modular mill design.

The mill stand design follows the require-

ments of the rolling process. The neces-

sary small work-roll diameter results

from the strength of the material and the

finish gauge to be achieved. Since the

degree of slenderness in the necessary

work-roll dimensions becomes too large,

these rolls need to be supported horizon-

tally. Lateral backup rolls, which are ad-

ditionally guided by two rows of backing

bearings, absorb the horizontal forces

and transmit them to the adjustable sup-

port bridges. The benefits of this mill

stand design mainly include the applica-

tion of the CVC plus® technology for set-

ting the roll-gap geometry, the use of the

HS (horizontal stabilization) system for

optimization of the horizontal forces and

above all a quick work and intermediate

roll change.

Another important criterion for the design

of a tandem rolling mill for cold-rolled

stainless steel strip is the temperature

control in the rolling process. The cooling

lubricant used to attain the required sur-

face finishes has a limited heat absorp-

tion capacity and the deformation energy

is predominantly transformed into heat,

i. e., the temperature of the material

rises. The compact design of the rolling

mill further allows the limited installation

of cooling sections. An exact prediction

of the material temperature forms the

basis for the production of excellent sur-

face finishes with very good gloss and

reflection properties.

The already mentioned cooling and

lubricant system of the rolling mill essen-

tially has to satisfy two requirements: on

the one hand it must support a high

thickness reduction at relatively low rol-

ling speeds while on the other hand it

has to produce the gloss properties of

the cold-rolled strip surface. The benefits

of SMS Demag's cooling lubrication

technology consist of the technological

know-how of the cooling lubricant's

pressure absorption capacity, lubrication

effect, cooling efficiency, the filter tech-

nology which for this rolling duty is based

on the SUPAFINE® technology and the

technological design of the coolant sys-

tem with the additional possibility of

setting different viscosity levels of the

lubricant in the various mill stands.

In SMS Demag's CVC® 18-HS rolling

mills, the potential flatness position er-

rors of the cold rolled strip are compen-

sated by tried-and-tested quick-response

actuators. Intermediate-roll bending and

edge-oriented shifting of the intermediate

rolls allow a very good correction of strip

edge waves and center buckles. How-

ever, the high degree of slenderness of

the work roll as well as the absence of

bending on the latter limit the potential

for correction in the case of so-called

quarter buckles.

To be able to use this additional adjust-

ment potential, SMS Demag has devel-

oped a special CVC plus® grinding for

the 18-HS rolling mills.

In addition to the expanded control range

of the roll-gap geometry, this CVC plus®

grinding features an improved distribu-

tion of rolling forces over the length of

the roll barrel and thus across the entire

strip width, thereby increasing the ser-

vice life of the rolls in the mill stands.

The HS system installed in

SMS Demag's rolling mills allows the

horizontal shifting of the work roll in the

direction of rolling as a function of the

predicted horizontal forces caused by

the drive torque. This allows high thick-

ness reductions during each rolling pass,

a longer service life of the lateral backing

elements and, through the integration of

the CVC plus® system in flatness control,

an excellent strip quality.

The HS system with its adjustable hori-

zontal offset of the work rolls reduces the

necessary supporting force which needs

to be absorbed by the lateral backing

elements. A more stable rolling process

and lower maintenance cost are the es-

sential benefits of this technology.

As a competent partner, SMS Demag

has a large number of reference installa-

tions at its disposal. This basis warrants

the efficient processing of projects as

well as a quick start of production. The

modular design of SMS Demag's rolling

mills, which has been successfully em-

ployed many times before, guarantees a

high availability and low operating cost.

SMS Demag offers rolling mill owners re-

liable solutions and high-quality engi-

neering at a cost-benefit ratio in line with

the market.


Applications

Continuous tandem cold mills for stainless steel

1969 1999 2007

Nisshin Steel

AK Steel

SMS Demagcontinuous

tandem mills

combined

stainless steel/carbon steel

stainless steel



▬ High productivity ⇒ capacity of more than 400,000 t/year

▬ Lowest conversion costs:

� highest yield

� less personnel

� low specific investment costs

▬ Excellent quality

▬ High flexibility compared to fully integrated lines

Advantages for stainless steel


Nisshin Steel

Continuous four-stand 20-high tandem mill


Main data

material: stainless steel

max. rolling speed: 600 mpm

capacity: 220,000 t/year

Existing plants


AK Steel

Continuous five-stand four-high/six-high tandem cold mill


Main data

material: carbon steel

stainless steel (austenitic, ferritic)

max. rolling speed: 1,900 mpm

capacity: 3,600,000 t/year

Existing plants


Four-stand CVC® 18-HS tandem cold mill


Main data

material: stainless steel

max. rolling speed: 400 mpm

capacity: 720,000 t/year

Advanced SMS Demag tandem mill


Increase in

output/yield

Continuous rolling,

two-high tension stand

Top surface quality for

subsequent processingSUPAFINE® filtration

Quick and reliable

strip surface controlInline inspection

Low maintenance and

operational costsModular and robust mill design

Wide range of products CVC® 18-HS technology


Tandem mill technology for stainless steel production



four-high

Admissibleandrequiredlineload[kN/mm]

Required line load for

strip thickness of 0.2 0.4 0.8 1.6 mm

Example:Tensile strength 1000 N/mm², reduction 40 %, strip width 1300 mm

CVC plus® 18-HS

Work roll diameter [mm]

no horizontal

stabilization requiredhorizontal

stabilization required

Line concept for cold rolling of high-strength steels


▬ CVC plus® technology

� improved roll gap setting and thusimproved strip flatness

� equal load distribution between therolls and thus reduced roll wear

▬ HS system (Horizontal Stabilization)

� reduced load of horizontal backingrolls

� less wear of backing rolls

▬ Easy roll change

� by installation of intermediate, workand backing rolls in change cassettes

Benefits compared to the conventional 18-roll mill


CVC plus® 18-HS



Simulation of strip temperature



Requirements from the rolling process

High reduction under

low rolling speed

Optimized roll coolant system

in terms of cooling,

lubrication and filtration

High-performance

rolling oil with excellent

lubrication and cooling properties

High surface quality

demands 2B



Advantages of SMS Demag coolant technology

Design of the rolling oil system allows

optimum adaptation to the rolling process

in terms of heat removal and lubrication.

Highest cleaning efficiency due to a

SUPAFINE® filtration system and

magnetic separator.

Environmentally friendly concept as

no filter aid is required.

Viscosity can be adapted to each mill

stand by means of inline coolers.



Available flatness actuators of 18-roll mills

flatness actuators

▬ IMR bending

▬ strip-edge-oriented

IMR shifting

flatness defects result

▬ small influence withIMR bending andconventional shifting

▬ insufficient influenceof multi-zone cooling

center buckles

edge waves

quarter bucklesno significant improvement

significant improvement

CVC® 18-HS



Principle of CVC® 18-HS

Axially shiftable IMR withspecial CVC® shape of

higher order

▬ Flatness control of higherorder � defects possible(strip edge and quarterbuckles)

▬ Due to special CVC® shapesmooth load distributionbetween WR and IMRachievable



Mill data:

WR dia.: 140 mm

IMR dia.: 355 mm

BUR dia.: 1,350 mm

Conventional

18-roll mill

Strip width: 1,200 mm

Spec. rolling force: 10 kN/mm

IMRshifting

IMRbending

Comparison: Roll-gap adjusting field on conventional

18-roll and CVC® 18-HS mills

CVC®18-HS

mill



CVC® 18-HS mill with reduced work roll diameters

Features Advantages

Reduced work roll diameters High thickness reduction possible

Horizontal Stabilization (HS) of Longer lifetime of side support

work rolls (SMS Demag patent) clusters due to adjustable force

Flatness control by proven IMR Excellent strip quality

bending and axial shifting system

(CVC plus® )

Horizontal Stabilization system (HS):

Work rolls can be laterally shifted depending on

strip data and rolling conditions.

▬ More than 15 references worldwide

▬ Ideal solution for stainless-steel tandem mills



Principle of Horizontal Stabilization system (HS)

With HS system:

supporting force can be adjusted

▬ Stabilized rolling process

▬ Longer lifetime of side support inserts

▬ Less maintenance

FTo

FD

FR

without HSHS systemsystem

requiredsupportingforce

FT1

rolling direction

FR � rolling force

FD � tangential drive force

FTo � strip tension force entry

FT1 � strip tension force exit

horizontal

roling force

component

e (shift)

with HS sHS systemystem

FTo

FD

FR

FT1

requiredsupportingforce = 0



Benefits of SMS Demag technology

▬ SMS Demag is a competent partner in process technology

▬ Great number of reference plants with proven

technology� fast start-up and reliable operation

▬ Low operational cost and high availability due

to modular design

▬ Excellent quality, high reliability, always on time

▬ Reasonable cost-benefit ratio

The new galvanizing linefor SeAH Steel –Results and experiences

Dipl.-Ing. Werner Haupt

General Manager

Preacquisition and Integrated Projects

Dipl.-Ing. Joachim Kuhlmann

General Manager Process Engineering

Strip Processing Lines Division

SMS Demag AG

Hilden, Germany

Y. J. Lee

Director

SeAH Steel Corp.

Kunsan-City, Jeonbuk, Korea

The new galvanizing line for SeAH Steel � Results and experiences

Y.J. Lee, Werner Haupt, Joachim Kuhlmann

The new and also first hot-dip galvaniz-

ing line of SeAH Steel Corporation is the

heart of the new cold rolling mill complex

built in Gunsan in the western part of

South Korea. The following topics report

on the construction of the facility by

SMS Demag as well as on our first oper-

ating results:

▬ General overview

▬ Market development

▬ Layout/technical data of the CGL

▬ Erection phase

▬ First coil

▬ Operation

▬ Results and experiences

SeAH Steel Corporation specializes in

the production of steel pipes, stainless

steel pipes for gas and water plumbing

installations in buildings as well as gal-

vanized strip and pre-coated material.

The annual production capacity is more

than 1,200,000 t.

Besides supplying the domestic market,

high export rates to the USA and Japan

are achieved.

The subsidiaries of SeAH Steel include:

▬ Busan Pipe America Inc. (USA)

▬ State Pipe & Supply Corp. (USA)

▬ Vinapipe Corp. (Vietnam)

▬ Saigon Steel Pipe Corp. (Vietnam)

▬ SeAH Japan Co., Ltd. (Japan)

The history of the company is as follows:

1960 Establishment of the company

as �Busan Steel Industry� in

Gammandong, Busan City.

1979 to 1982 � Acquisition of several

specialist companies for the pro-

duction of steel pipes.

1996 The company�s name was

changed into �SeAH Steel

Corporation�.

2005 Completion of the new cold

rolling mill complex in Gunsan.

As part of the new cold rolling mill

in Gunsan, the agreement with

SMS Demag for the supply of a hot-

dip galvanizing line was signed on

November 28, 2003.

With a market share of 660,000 t, SeAH

Steel covers 22 % of the demand for

steel pipes in the South Korean market

and is South Korea�s biggest enterprise

in this product sector.

With 350,000 t of cold rolled steel, gal-

vanized and pre-coated strip, SeAH

holds just a small market share among

the big players and has to compete with

producers which, owing to the size of

their companies, are able to produce

high-grade products at favorable cost.

The new galvanizing line has been de-

signed for the production of hot-dip gal-

vanized steel strip of the steel grades

CQ, DQ, DDQ and FH (full hard). These

products are used for white goods, in

the electrical and building as well as the

construction industries.

Designed for an annual capacity of

300,000 t, the line galvanizes strip 0.23

to 1.8 mm thick and 600 to 1,300 mm

wide. In the coating section, the strip

runs at speeds of up to 200 m/min, while

the entry and exit sections attain speeds

of maximum 280 m/min.

The line configuration is following the

demand for hot-dip galvanized strip of

highest surface quality. Pre-cleaning

takes place in the entry section and full

cleaning right upstream of the furnace.

To facilitate installation, the vertical strip

loopers feature a new modular design.

They are completely balanced and

equipped with a redundant drive system

with amply dimensioned ropes to ensure

reliable operation and a long service life.

The radiant-tube-heated Drever furnace

with a capacity of 73 t/h and the highly

precise Duma air-knife system complete

the process section.

Downstream of the four-high skin-pass

mill and the tension leveler unit, a ver-

tical coater takes care of passivating the

strip.

The new galvanizing line of SeAH Steel

was built by a consortium comprising

SMS Demag AG, Germany, Drever

International S.A., Belgium, and Duma

GmbH, Germany.

Picture 6 shows the steel structures of

the two cleaning sections during erec-

tion.

Picture 7 on the left shows the area of

the post-treatment section during instal-

lation. The picture on the right reflects

the line from the entry looper system, via

the center cleaning section up to the

vertical furnace.

Erection started in November 2004 and

was completed in June 2005. In total,

more than 4,000 t of machines and steel

structures were installed. As early as

21 months after contract signing, the

first galvanized coil was produced.

Thanks to the excellent performance of

all suppliers under the leadership of

SMS Demag and the superb coopera-

tion between the consortium and SeAH

Steel, the first saleable strip was pro-

duced four weeks before the scheduled

contractual date.

Picture 8 shows the festive celebration

of production start, which is a very im-

portant ceremony in the Korean self

understanding and culture.

As a result of this early and successful

hot commissioning, the full production

capacity was already achieved after

23 months and the Final Acceptance

Certificate (FAC) was issued as soon as

after 21 months.

Picture 9 on the top shows the vertical

post-treatment section in operation with

roll coater, drying oven and air coolers.

The right bottom picture reflects the op-

eration of the line in the area between

the pre-cleaning section and the vertical

furnace. The picture provides a clear

view of the entry-end vertical looper ar-

ranged between the two cleaning sec-

tions. The picture on the left is a top

view of the Duma air-knife system.

The remarkably steep run-up curve of

the line is documented by the following

production evaluations covering the ini-

tial months after line startup.

▬ Run rate

▬ Production volume

▬ Yield

▬ Run-up curve

▬ Coating tolerances or accuracy

Already in the first month, the line at-

tained a relatively high availability of

74.5 %, and from the end of the third

month on, the values stabilized around

the target of 98 %.

Picture 12 reflects the volumes pro-

duced for direct sales and for processing

in the own color-coating section.

It is obvious also in this case that the

line achieved its planned production

after a short time.

Picture 13 represents the ratio between

input material and finished products. A

high value means, for example, low

scrap losses. As early as in the second

month, the target value of 98 % was ex-

ceeded. Values of over 100 % may re-

sult owing to a weight increase due to

coating.

The run-up curve is the best way to de-

scribe the performance of the line as a

combination of availability and yield.

Just one month after commissioning, the

value stabilized around the target of

96 %, and after eight months ideal val-

ues of nearly 100 % were achieved.

The coating accuracy is one of the most

important factors for the product quality

and, when zinc prices are high, decisive-

ly impacts the operating costs.

Thanks to the Duma air-knife system,

coating uniformity is more than satis-

factory. Currently, each 1 % in closer

coating tolerances reduces operating

costs by up to EUR 1 million per year.


The new galvanizing line for SeAH Steel

Contents

General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences

▬ General overview

▬ Market developments

▬ Layout/Technical data

▬ Erection phase

▬ First coil

▬ Operation

▬ Results and experiences



Company profile

SeAH Steel Corporation is specialized in the production of

▬ steel pipes,

▬ stainless steel pipes for plumbing and structures,

▬ galvanized steel and pre-coated metal

Annual production capacity: 1,200,000 t of steel products

Export of products to the USA and Japan

Subsidiaries:

▬ Busan Pipe America Inc. (USA)

▬ State Pipe & Supply Corp. (USA)

▬ Vinapipe Corp. (Vietnam)

▬ Saigon Steel Pipe Corp. (Vietnam)

▬ SeAH Japan Co., Ltd. (Japan)

General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences



Company history

1960 Establishment of the company as �Busan Steel Industry

in Gammandong, Busan City

1979 - 82 Several acquisitions of specialized companies

1996 Change of company name into SeAH Steel Corp

2005 Completion of new CRM in Gunsan area

28.11.2003 Purchase agreement with SMS Demag

for the new CGL

General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences



Market shares

52.71,591Others

1003,019Total

Husteel

SeAH Steel

Hysco 16.4495

21.9660

9.0273

Portion

in %

Market

share

7.8932Union Steel

10.61,258Others

10011,910Total

Dongbu Steel

Posco

Hysco 12.11,437

54.16446

15.41,837

Portion

in %

Market

share

General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences

Market share Cold rolled steel

(in '000 t)

Hysco

Posco

Dongbu

Steel

Union

SteelOthers

Market share steel pipe

(in '000 t)

Hysco

Seah

Steel

Husteel

Others



Technical Data:

Products: GI / CQ, DQ, DDQ, FH (full hard)

Application: White goods + construction

Production capacity: 300,000 t/year

Strip thickness: 0.23 to 1.6 mm

Strip width: 600 to 1,300 mm

Line speed: 200 m min (process section)

General

overview

Market

development

Layout

Erection phase

Operation

Results and

Experiences

Continuous galvanizing line � SeAH Steel, Korea



Erection phase

All main equipment by SMS group

General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences

Continuous galvanizing line

was built by a consortium

between

▬ SMS Demag AG, Germany

▬ Drever International S. A.,

Belgium

▬ Duma GmbH Germany

for air knife system



Erection phase

General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences

▬ 21 months from purchase

agreement to first coil

▬ erection period November 2004

until June 2005

▬ total weight: 4,114 t



The first coil was produced in saleable quality

four weeks before scheduled date

General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences



Operation

Cleaning section,

entry looper and furnace

Air knife

Post treatment

▬ FAC after 21 months

▬ Full production after 23 months

General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences



Results and experiences

General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences

▬ Run rate

▬ Production of main products

▬ Benefit (output/input)

▬ Startup curve

▬ Coating accuracy



Run rate (prod. time/planned prod. time)

70

75

80

85

90

95

100

Sep 05 Oct 05 Nov 05 Dez 05 Jan 06 Feb 06 Mar. 06 Apr 06 May 06

Month

Rate(%)

Run rate target 98 %

First month

273hrs

437.7hrs

306.7hrs 405hrs

576.9hrs

491.4hrs

602.6hrs

600.4hrs

588.6hrs

hrs: Production hours


General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences



Production

-

5.000

10.000

15.000

20.000

25.000

Sep

05

Oct

05

Nov

05

Dez

05

Jan

06

Feb

06

Mar

06

Apr

06

May

06

Month

tons/month

GI FOR SALE MATERIAL FOR CCL TOTAL


General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences



Benefit (output/input)

70

80

90

100

110

Sep 05 Oct 05 Nov 05 Dez 05 Jan 06 Feb 06 Mar 06 Apr 06 May 06

Month

Rate(%)

Benefit target 98%

First month


General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences



Startup curve

0

10

20

30

40

50

60

70

80

90

100

Sep 05 Oct 05 Nov 05 Dez 05 Jan 06 Feb 06 Mar 06 Apr 06 May 06

Month

Rate(%)

Target startup curve 96 %

First month


General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences



SeAH is very satisfied with the achieved coating

tolerances of the Duma air knife. Due to increased zinc

costs each 1 % improvement of tolerances reduces our

operation costs by approx. 1 million EUR per year.

Coating tolerances

General

overview

Market

development

Layout

Erection phase

First coil

Operation

Results and

experiences

Economical solutions forhigh-quality processing lines

Dipl.-Ing. Stefan Melster

General Manager

Technical Sales


Dr. Hans-Georg Hartung



SMS Demag AG

Hilden, Germany

Economical solutions for high-quality processing lines

Stefan Melster, Dr. Hans-Georg Hartung

While in the past many investment deci-

sions were clearly made on the grounds

of technical preferences, the majority of

decisions nowadays is based on eco-

nomic considerations or facts. The refer-

ence figure today is the total cost, fig-

ure 1. Costs such as the percentage of

depreciation, overheads and the prices

of raw materials cannot be influenced by

plant builders. Investment cost or, in

other words, the price of the line is a

matter of technical requirements and so-

lutions or, respectively, a matter of nego-

tiation and by far not the most important

factor. In the long run, it is the cost for

maintenance, yield loss, staff and con-

sumables that makes the difference be-

tween standard lines and economically

and profitably operating processing lines.

For about ten years, our development of

new equipment and the optimization of

existing components have been follow-

ing just one guideline � to improve the

customer benefit and profit. This can on

the one hand be achieved by technical

improvements which have an economic

impact, but also by cost-cutting with a

subsequent price reduction which is

based on a different design, but does not

affect equipment performance.

SMS Demag today offers the full range

of high-quality strip processing lines with

obviously significant economic advan-

tages, figure 2, as demonstrated by the

large number of recent references. Be-

sides 13 continuous pickling lines and

coupled pickling lines/tandem cold mills,

six color coating lines, twelve continuous

annealing lines and 14 galvanizing lines,

SMS Demag has during the last six

years received orders for more than

70 further strip processing lines. Among

these are high-tech lines like silicon strip

processing lines, processing lines for

aluminum strip or acid regeneration

plants.

Figure 3 is a summary of our latest ma-

jor worldwide references. Our guideline

for achieving best total cost of ownership

can be best explained by two recent ex-

amples: the pickling line of the new

coupled pickling line/tandem cold mill of

Baosteel�s cold rolling mill No. 5 and the

continuous galvanizing line No. 3 of

US Steel Kosice in Slovakia.

Figure 4 is a sectional view of Bao-

steel�s new PLTCM, designed for an an-

nual production capacity of 1.74 million t

of steel, mostly high-quality grades for

the automotive industry. To explain the

cost-saving potential of our technologies,

three examples are provided of which

more details will be shown:

▬ the turbulence pickling technology

▬ the horizontal loop accumulator

▬ the ASC side trimming shear

Since the early 50s, SMS Demag has in-

fluenced the design of all types of high-

performance pickling lines all over the

world. Meanwhile all components for

pickling lines including mechanical and

chemical equipment, even acid regener-

ation plants and laser welding machines,

can be supplied from one single source.

This is a benefit to our customers as it

involves a consistent process technology

and minimizes potential interface prob-

lems.

The turbulence pickling method, fig-

ure 5, developed by SMS Demag, is not

only the most effective, but also the most

economical pickling technology in terms

of operating cost. The design of

SMS Demag�s turbulence pickling line is

characterized by shallow and horizontal

pickling channels, the patented immer-

sion covers and acid injection by spray

headers on the entry and exit sides of

each pickling tank. The straight, horizon-

tal channel which is integrated into the

main pickling tank, allows operation of

the line at high strip tension for improved

strip guiding. Its small height of about

150 mm not only ensures a high acid

flow velocity and hence large turbu-

lences, but also a much faster adjust-

ment of the acid temperature, due to less

acid circulation volumes. This improves

process flexibility. The immersion cover

seals off the pickling channel towards

the top and thus prevents any free acid

surface and acid evaporation in the pick-

ling tank, which leads to significant ener-

gy and operating cost savings. By injec-

ting the acid at high pressure from the

entry and exit sides into the pickling

channel and onto the strip, the turbulent

acid flow and the acid exchange on the

strip surface are increased through the

high input of kinetic spraying energy.

During the pickling process the entire

pickling channel is filled with acid,

whereas the entry- and exit-side acid in-

jection serves for hydrodynamic sealing

of the pickling channel, figure 6. This

ensures wetting of the full strip surface

even at high strip speeds, as well as an

improved acid separation between the

pickling tanks. The high intensity of the

turbulence pickling line allows a very

compact design of this process section.

Steam and power consumption as well

as acid losses are significantly lower

than in conventional pickling systems,

due to the immersion covers. A much

faster heat transfer from acid to strip and

more intensive acid exchange at the strip

surface can be achieved through the

high kinetic spraying energy. This leads

to a better acid utilization and an accel-

erated pickling process. Due to the good

controllability of the process, no pickling

inhibitors are necessary. The rinse sec-

tion has a second spray rinse circuit in

order to avoid staining during line stops.

Therefore, no rinsing inhibitors are

needed here either. For a pickling line

with a production capacity of about

1.8 million t/year, annual savings may

total 600,000 EUR just because of the

above-mentioned features.

The turbulence pickling process can be

further optimized through the application

of SMS Demag�s process model, fig-

ure 7, which sets all essential pickling

parameters to the relevant strip quality

automatically and ten to 20 coils in ad-

vance. The main objective is to prevent

underpickling or overpickling and to set

the lowest possible acid temperature.

The lowest possible bath temperature

means minimum energy and acid con-

sumption, but also an increased lifetime

of all equipment exposed to acid. A 5 °C

drop in the bath temperature may result

in a 50 % longer lifetime of plastic pipes.

Part of this process model is the simula-

tion of the pickling process for incoming

coils. Based on all major pickling and

strip parameters, the pickling result can

be controlled by the correct setting of the

acid pressure in consideration of the

strip speed and the required bath tem-

perature. The model controls the transi-

tion from one strip to the next, so that the

pickling process is adapted to the next

strip without any visible change in the

pickling results. In addition to the above-

mentioned cost savings, the application

of the SMS Demag process model may

result in further savings of up to

300,000 EUR per year due to reduced

power and fluids consumption.

SMS Demag�s horizontal looper system,

figure 8, is characterized by two main

features: the retained looper car and the

Maltese-cross looper gate design. The

retained looper car means that the

looper car is pulled on each side by

ropes, whereas other systems use a

rope for pulling on one side and the strip

only for pulling on the other side. The ad-

vantages of our system are lower ten-

sion fluctuations and a more stable

looper car operation. Constant strip ten-

sion and thus untroubled operation of the

coupled tandem mill is not the only bene-

fit of the closed loop system. For mainte-

nance purposes the looper car can be

moved without strip in the line.

Due to the Maltese-cross looper gate

system, the looper gate arms can be

opened and closed smoothly by the

looper car without any shock even at

high looper car speeds. The special me-

chanism leads to a soft acceleration and

deceleration of the looper arm without

inertia-caused overloading of the me-

chanical parts. Frequent consequential

damage can thus be avoided. Each da-

maged gate costs a total of approx.

90,000 EUR. These expenses for

spares, maintenance work, production

loss and fixed costs can be saved.

The combined ASC side trimmer and

chopper unit is one of the most impres-

sive cost savers in our lines, figure 9.

On each side of the line two trimming

shears with associated scrap choppers

are mounted on a turntable platform in a

180-degree arrangement. This arrange-

ment allows the safe maintenance of the

standby trimmer/scrap chopper unit also

during production, with the other unit in

operation. All settings of the knife gap

and knife overlap are performed

automatically by eccentrics. In

comparison, linear shifting devices with

bushes tend to wear and are always a

matter of maintenance. In contrast, ec-

centrics are backlash- and almost main-

tenance-free. Due to the automatic knife-

gap and knife-overlap setting, an ex-

tended lifetime of the blades and im-

proved cutting qualities can be achieved.

The knife blades are face-ground and

mounted against mechanical stops,

therefore no calibration is required after

a blade change.

The side-trimmings chute between the

trimmer and chopper is undivided with-

out any gaps. Gaps in the side-trimmings

chute are usually the cause of scrap

cobbles and each cobble can take

approximately one to two hours to be

removed.

During a width change, the complete

side trimmer and chopper unit will be re-

adjusted within seconds without produc-

ing any extra scrap. Our design avoids

the above-mentioned typical operational

problems, i. e. unscheduled downtimes

for troubleshooting like scrap jam remov-

al. Even in the unlikely case of trouble or

in case of normal maintenance, the

whole system together with its problem

is simply turned out of the line and re-

placed by fully operative equipment with-

in 60 seconds. The problem can then be

fixed in the safe 180-degree position

while the line is running. With one

trouble per week, this ASC side trimming

system can save up to 1 million EUR per

year in high-performance pickling lines.

The combined ASC side trimmer unit is

not only used in our pickling line, but al-

so in most of our other strip processing

lines.

Another good example for economical

processing-line solutions is the new gal-

vanizing line No. 3 of US Steel Kosice,

figure 10. This is a typical line for the

production of exposed automotive mate-

rial with GI and GA coatings. Highly so-

phisticated structural steel grades are al-

so part of the product mix.

The total-cost-of-ownership guideline is

explained by the following examples:

▬ Coil transport system

▬ Cleaning section

▬ Air knife

▬ Post-treatment/coating section

Our coil cars, figure 11, are of extremely

compact and flat design and do not need

any deep, expensive and eventually also

dangerous foundation pits. Still they are

as sturdy as necessary for metallurgical

works. As opposed to other scissors-

type coil cars, the cylinder force acts in

the load direction and not in transverse

direction. The scissors just have a guid-

ing function, but do not transmit any

load. Besides safety and maintenance

aspects, the cost reduction for the foun-

dations of three coil cars is about

70,000 EUR.

Our strip cleaning sections, figure 12,

are characterized by three main fea-

tures. First, sealed modules with lower

required fume exhaust volumes at the

connection points of the modules reduce

energy losses significantly. Second, the

changing of rolls is fairly easy and can

be done during operation with no addi-

tional downtimes or maintenance work

required. Finally, special tongue-shaped

spray nozzles guarantee a clog-free op-

eration. No clogging means no surface

stripes, no subsequent downgrading and

no prematurely damaged brush rolls.

Based on European cost basis, up to

600,000 EUR can be saved per year.

SMS Demag can provide two prime-

quality air knife systems: Fontaine and

Duma, figure 13. Both air-knife systems

are technically excellent. Both can be

equipped with width-adjustment actua-

tors without any negative influence on

the surface quality produced. Depending

on the product mix, such a blow-off width

adjustment can save up to 30 % of com-

pressed air or, respectively, nitrogen. In

the production of automotive strip such

nitrogen savings can add up to

1 million EUR a year in case the nitrogen

has to be purchased. The high precision

of our air knife systems results in closer

coating tolerances than in other systems.

A mere 1 % more precise coating can

save zinc worth up to 1 million EUR per

year in a typical hot-dip galvanizing line

producing approx. 400,000 t/year and

approx. 190 million m² strip surface.

In modern lines that conform to the latest

health and safety standards, the heart of

the post-treatment section is the roll

coater, figure 14. Using two separate

circuits, our coaters can be used for

chromating as well as anti-fingerprint

coating. Due to the use of coated pans

and the automated cleaning and rinsing

system, a change in coating agent is not

very time-consuming. Alternatively, a

two-coater or shuttle coater system can

be provided. The rolls can be changed

without any major maintenance effort.

But the most impressive property is no

doubt the outstanding accuracy of the

coating. With this system, a coating ac-

curacy of plus/minus a quarter of a mi-

cron can be achieved. In comparison

with other coating systems with ac-

curacies of plus/minus 1 micron, this

means, in addition to other benefits, sav-

ings of up to 500,000 EUR per year for

the post-treatment system of hot-dip gal-

vanizing lines. In color-coating lines,

three times this amount can easily be

saved due to the particularly high cost of

chemicals and paints.

All the above-mentioned examples are

the result of a continuous improvement

process, figure 15. All developments

must follow the total-cost-of-ownership

guideline. This means that improve-

ments must pay off to our customers in

terms of reduced operating cost, less

energy consumption, less maintenance,

less downgrading, higher yield or a mar-

ketable better product quality. All these

economical solutions for high-quality pro-

cessing lines are incorporated in our lat-

est reference list and have been suc-

cessfully commissioned. As a conse-

quence, a steep ramp-up curve is part of

our customer benefit.



Introduction

Introduction

Strip

processing

lines

Pickling line

technology

Summary

No cost influence

by SMS Demag

Cost influence

by SMS Demag

Investment

cost

Overheads Depreciations

Total cost

of ownership

Staff costYield loss

Consumables

& mediaMaintenance

Raw material

Hot-dip

galvanizing line

technology


Strip processing lines � Major references since 2000


Carbon steel

� in total more than

50 new processing lines

since 2000

� incl. seven lines for

silicon strip

� incl. seven lines for

aluminum strip �

� plus approx.

60 service lines �

� plus 13 new ARPs

13 CPL/PLTCMs

14 CGLs

12 CALs

6 CCLs

1 ETL

Introduction

Strip

processing

lines

Pickling line

technology

Summary

Hot-dip

galvanizing line

technology



Strip processing lines � Major references since 2003Customers and type of lines

Introduction

Strip

processing

lines

Pickling line

technology

Summary

Tokyo Steel CPL + ARP

Shougang Jing-Tang CAL

Nucor CGL

ILVA Taranto and Cornigliano 2 CGLs

Baosteel 4 Si-lines

Tiantie PLTCM

Salzgitter CPL

SeverCorr CGL + PLTCM

Baosteel CAL + PLTCM

Shougang CAL + PLTCM

US Steel Kosice CGL

Jinan CPL

WISCO 3 CGLs + CAL + PLTCM

Anshan CAL

Seah CGL

Rasselstein ETL

Baosteel CAL + PLTCM

US Steel Kosice CGL

Hot-dip

galvanizing line

technology


Introduction

Pickling line

technology

Summary

Products:

Strip thickness

Strip width:

Pickling speed:

Production capacity:

CQ, DQ, DDQ, EDDQ, SEDDQ, DP, Trip

1.8 to 6.0 mm

700 to 1,650 mm

270 m/min

1,740,000 t/year

Technical data


Pickling line/tandem cold millBaosteel, Baoshan/China

Hot-dip

galvanizing line

technology



Turbulence pickling technology

��

�

�

� Turbulence pickling channel

� Immersion cover

� Outer cover

� Pickling tank

▬ Flat and horizontal pickling channel

▬ Immersion covers � less acid evaporation

▬ Hydrodynamic sealing

Introduction

Strip

processing

lines

Pickling line

technology

Summary

Hot-dip

galvanizing line

technology


▬ Better controllability due to less acid volumes in circulation

▬ Less steam, acid and energy consumption due to immersion covers

▬ No pickling and rinsing inhibitors

▬ Lower possible acid temperature � less energy, longer lifetime



Turbulence pickling tank with circulation system

Total potential on cost savings: up to 600,000 EUR/year

Draining chamber with spray bars and

squeegee roll unit (hydrodynamic sealing)

Acid supply

pipingCascade piping

Pump

Heat exchanger

Steam

Condensate

Waste acid

Introduction

Strip

processing

lines

Pickling line

technology

Summary

Hot-dip

galvanizing line

technology




▬ Minimized overpickling:

� less material loss

� less energy

� higher yield

▬ Automatic setting and control of process actuators

▬ Minimized bath temperature

� less energy

� longer lifetime

� less maintenance

Total potential on cost savings:

up to 300,000 EUR/year

SMS Demag process model for turbulence pickling

Turbulence

Temperature

Desired bath temp.Strip speed

Introduction

Strip

processing

lines

Pickling line

technology

Summary

Hot-dip

galvanizing line

technology



High-speed looper concept � Technical advantages

Steering Curve

Tension Rope

Retaining Rope

Each damaged gate costs EUR 90,000

Introduction

Strip

processing

lines

Pickling line

technology

Summary

Maltese-cross looper gates

▬ impact-free opening and closing

▬ less damages

▬ longer lifetime

▬ less maintenance

Hot-dip

galvanizing line

technologyClosed loop system(two-side rope pulling)

▬ less tension fluctuation

▬ better maintainability



ASC trimming shear

Features:

▬ No line stop during

knife change

▬ Easy and safe

maintenance access

▬ No extra scrap during

width change

▬ No calibration of knives

after change

Potential cost savings up to 1 million EUR/year

due to less downtime

Introduction

Strip

processing

lines

Pickling line

technology

Summary

Hot-dip

galvanizing line

technology


Products:

Strip thickness

Strip width:

Process speed:

Production capacity:

CQ, DQ, DDQ, EDDQ, SEDDQ, HSS-CQ,

HSS-DQ, HSS-DDQ, BH, DP

0.3 � 2.0 mm

800 � 1,850 mm

180 m/min

410,000 t/a

Technical data:


Continuous galvanizing lineUS Steel Kosice, Slovak Republic

11

Coil transport systems


SMS Demag technology

▬ Coil cars with extremely flat

design and rigid design for

metallurgical works

▬ Guiding scissors are load-

free

▬ No expensive and

dangerous foundation pits

▬ Good maintainability

Reduction of foundation cost

up to 70,000 EUR

Introduction

Strip

processing

lines

Pickling line

technology

Summary

Hot-dip

galvanizing line

technology


Potential cost savings: up to 600,000 EUR/year



▬ Sealed modules � less energy

▬ Easy roll changes � less

maintenance

▬ No clogging � no brush roll

damages, no stripes, no

downgrading

Strip cleaning section

Introduction

Strip

processing

lines

Pickling line

technology

Summary

Hot-dip

galvanizing line

technology



▬ Width adjustable

▬ Outstanding coating accuracy

▬ Minimized over-coating

Possible reduction of production costs per year:

� up to EUR 1,000,000 nitrogen savings for customers

without oxygen plants

� 1 % better coating accuracy = approx. 1,000,000 EUR

cost savings for zinc

Air knife


Introduction

Strip

processing

lines

Pickling line

technology

Summary

Hot-dip

galvanizing line

technology



▬ Outstanding coating accuracy

▬ Simple roll change

▬ Automated cleaning of rolls, pans

and media systems

▬ Minimized over-coatings due to

higher coating accuracy

Post-treatment


A coater accuracy of ± 0.25 μm instead of

± 1.0 μm can save up to 500,000 EUR/year

for post-treatment

Introduction

Strip

processing

lines

Pickling line

technology

Summary

Hot-dip

galvanizing line

technology


Summary

▬ Cost savings resulting from �

� less operating materials and energy consumption� less maintenance and longer service life� less downgrading of product quality� less downtimes and higher yield

▬ Better product quality

▬ Higher flexibility and faster start-up curves

The essentials of economical solutions are �


Introduction

Strip

processing

lines

Pickling line

technology

Summary

Hot-dip

galvanizing line

technology

The SMS Demag laser weldingmachine

Dipl.-Ing. Lutz Kümmel

Senior Project Manager


Dr. Hans-Georg Hartung



Dipl.-Ing. M.B.M. Markus Jaenecke

Senior Project Manager Project Planning


SMS Demag AG

Hilden, Germany

The SMS Demag laser welding machine

Dr. Hans-Georg Hartung, Markus Jaenecke, Lutz Kümmel

Some three years ago, SMS Demag and

Oxytechnik, a German welder manufac-

turer, agreed to jointly develop a laser

welder for strip processing lines. Tech-

nology and design are the results of

many years of experience in designing

high-performance strip processing lines

and equipment as well as welding ma-

chines including laser welders for special

applications.

Nowadays, laser welding machines are

the first choice for continuous pickling

lines. These welders are meanwhile

cheaper than flash butt welders and

easier to commission, especially if new

materials or material combinations are to

be welded. In addition, these welding

machines are able to weld thinner strip

and strip with higher amounts of alloying

elements. Based on the experiences

gained from many projects, we devel-

oped a new laser welder design. Thanks

to the closed-frame concept, the ma-

chine is more compact than C-frame-

type machines and can usually be trans-

ported on trucks.

The laser resonator is fixed on a sepa-

rate foundation. No resonator vibrations

will influence the welding accuracy. For

maintenance purposes, access to the

machine as well as to the resonator is

excellent.

Another remarkable feature is the posi-

tioning system that aligns the head end

of the new strip with the tail end of the

previous strip. That means that it is the

center line of the leaving strip that de-

fines the correct alignment, and not the

center line of the machine. After joining,

the two strips will have one common

center line and definitely no so-called

dog-leg shape. One of the biggest ad-

vantages is that the strip edges will not

be damaged. The clamping of the strip

will not be interrupted until welding is

finished.

The integrated shear is not a notcher-

type shear with more or less no gap be-

tween top and bottom knives. Such a de-

sign leads to huge perpendicular forces

acting on the knives and subsequently to

high wear and less accuracy. The laser

welder consists of a robust, mill-type-de-

sign dividing shear with automatically ad-

justable knife gaps separately for the

outgoing and ingoing strip ends. The

knife crossbeam is supported at several

positions across the width and doesn�t

allow any relevant breathing. The blade

lifetime is at least three times as long as

for other laser welders and, due to the

cassette design, the blades can be

changed easily by an electro-hydraulical-

ly changing device. The top knife can be

used twice, the bottom knives four times

before regrinding. The precise cut has

the potential to allow using lasers with

less power in the future because the de-

focusing of the beam can be reduced.

This leads to less laser power and con-

sequently to a longer laser lifetime. For

the same reason we expect that more

and more Neodymium-YAG lasers will

be used in the near future instead of

high-power CO2 laser sources. One ma-

jor advantage is the possibility to feed

the beam via fiber-optic cable to the weld

spot � subsequently no mirrors can be

contaminated.

The shear remains in the machine during

welding. Therefore, we could avoid the

either heavy or flimsy C-frame design.

Scrap can be discharged directly into a

pit or be removed by a conveyor belt.

In case of different strip thicknesses, the

joint can be made centrically, top side or

bottom side orientated. Real zero-gap

welding is possible due to the shifting

function of the strip clamping device.

As an option for special applications a

wire feeder can be provided. Mixed gas

or helium is used as inert gas.

Along with the design work plenty of

laboratory tests were conducted. The

test results were very promising, even

for hard-to-weld steel grades like C60

with a carbon content of 0.67 %. The

cross-sections of the welds were excel-

lent and so were the microstructures of

the heat influence zone and of the weld

itself. The main components of the mi-

crostructure of this high-carbon steel are

ferrite and perlite. Post-annealing and

particularly preheating and post-anneal-

ing led to a highly uniform hardness dis-

tribution in the vicinity of the weld as

compared to the results without anneal-

ing. In order to ensure the best possible

heat treatment of the weld, new inductive

pre- and post-heaters were developed

together with our sister company

SMS Elotherm. The main features are

fast heating during preheating and post-

annealing with retarded cooling.

Early in 2006, we received an order from

Salzgitter Flachstahl GmbH, Germany,

for a heavy-duty laser welding machine.

This laser welder for 800 up to 1,900-

mm-wide strip will be installed in a 2.5-

million-t/year continuous pickling line that

will also be supplied by SMS Demag.

The strip thickness ranges between 1.5

and 6 mm and the yield stress may ex-

ceed 1,100 N/mm². Some of the steel

grades are extremely difficult to weld

such as C60. The laser welder for Salz-

gitter is currently being tested in our

workshop. In April 2007 Tokyo Steel,

Japan, placed a further order for a laser

welder with us.



Development of SMS Demag laser welding machine

▬ In 2004, a cooperation between SMS Demag and

was established in order to develop a

laser welding machine for strip processing linesIntroduction

Main features

Laboratory test

Laser welding

machine for

Salzgitter



Laser beam source

CO2 laser resonator

Introduction

Main features

▬ The laser resonator is fixed

beside the machine on a

separate foundation

▬ No vibrations, no influence

on the welding accuracy

▬ Easy access for maintenanceLaboratory test

Laser welding

machine for

Salzgitter



Strip alignment

Introduction

▬ Incoming strip head is aligned with the tail end of the

previous strip

▬ Center line of the leaving strip defines the right alignment

▬ No pushers � no strip edge can be damaged

Laboratory test

Laser welding

machine for

Salzgitter

Main features



Shear design

▬ Robust, mill-type design dividing shear with automatically

adjustable knife gaps separately for outgoing and ingoing

stripIntroduction

Laboratory test

Laser welding

machine for

Salzgitter

Main features



Shear design details

Introduction

▬ Knife lifetime triples

▬ Quick knife changes

▬ Precise cuts =

precise weld

Multiple support of knife crossbeam

Knife changing device

Laboratory test

Laser welding

machine for

Salzgitter

Main features



Welding process

Introduction

▬ The joint can be made

centrically, top side or

bottom side oriented

▬ For special steel grades a

wire feeder can be installed

▬ For shielding, mixed gas or

helium is used

Laboratory test

Laser welding

machine for

Salzgitter

Main features



Results of laboratory test

Introduction

Main features

▬ Cross-sections of the welds as well as the microstructure of

the heat influence zone and of the weld itself were excellent.

▬ Hard-to-weld steel grades

like C60 with a carbon

content of 0.67 %

were welded successfully

Laboratory test

Laser welding

machine for

Salzgitter



Influence on weld seam hardness by heat treatment

Preheating and post-

annealing of coils

Introduction

Main features

▬ Fast preheating and soft post-

annealing with retarded cooling

200

300

400

500

600

700

800

900

1000

-5,0 -4,0 -3,0 -2,0 -1,0 0,0 1,0 2,0

Position [mm]

HV1

Probe 10.2

Probe 8.2

Probe 5.1

Pr. 5.1, Grundwerkstoff

C60, Anlieferung

Laboratory test

Laser welding

machine for

Salzgitter



The new laser welding machine will be installed

in the new 2.5-million-t/year continuous pickling line

of Salzgitter Flachstahl GmbH

Introduction

Main features

▬ The order was placed in March 2006

▬ Carbon content up to 0.67 %

▬ Strip width between 800 and 1,900 mm

▬ Strip thickness between 1.5 and 6 mm

▬ Yield stress up to 1,100 N/mm²

▬ Pre-commissioning underway in our Hilchenbach

workshop

Laboratory test

Laser welding

machine for

Salzgitter

Innovative and flexible:the Automatic Coil Transporter(A.C.T.®) developed by SIEMAG

Dipl.-Ing. Bernd Klein

CEO

Dipl.-Ing. Volker Schneider

Project Manager Sales

Dr. rer. nat. Horst Thorn

Head of Sales Department

SIEMAG GmbH

Netphen, Germany

Innovative and flexible:

The Automatic Coil Transporter (A.C.T.®) developed by SIEMAG

Bernd Klein, Horst Thorn, Volker Schneider

Nowadays, flexibility and automation are

two of the most important objectives in

logistics planning. The operators of pro-

duction plants are obliged to respond

quickly and flexibly to changes in general

conditions. The Automatic Coil Trans-

porter (A.C.T.®) developed by SIEMAG

guarantees the maximum degree of flexi-

bility required.

Many production plants in the steel, NF

metals and paper industries have grown

gradually over decades with investments

made mainly in new machines and mod-

ernization of existing ones.

Due to increases in production volumes,

problems frequently occur with the logis-

tics of the coils to be stored and trans-

ported.

Conventional conveyors such as walking

beams, chain conveyors or track-guided

cars can often only be integrated in ex-

isting production facilities at considerable

cost and effort. In particular, the founda-

tion work required often leads to serious

disruption of the existing infrastructure.

Existing traffic routes and machinery

often prevent conventional solutions

from being adopted.

In situations such as these, the A.C.T.®

developed by SIEMAG represents the

perfect solution.

Thanks to the laser navigation system,

the A.C.T.® can be used without having

to modify the existing transport routes.

The plant layout is stored in the naviga-

tion computer and all the possible routes

are programmed.

The overriding vehicle-management

computer selects the best available

vehicle and determines the best route

taking both source and destination into

account.

This route is then transmitted to the

vehicle by radio.

With the assistance of the navigation

laser and reflective foils mounted on the

building structure at a height of about

4 meters, the vehicle always knows ex-

actly where it is and is therefore able to

cover the preset route automatically.

Communication with the host computer

also takes place at crossings, control

lights or gates, and the computer de-

cides which of the vehicles has priority.

Traveling on and crossing these routes

with driver-controlled vehicles represents

no problem. Priority regulations can be

defined at points with a high traffic fre-

quency and the drivers signal their arriv-

al and departure simply be pressing a

switch.

The A.C.T.® on the other hand is fitted

with an elaborate safety system which

detects obstacles in good time and

brings the vehicle to a halt before a colli-

sion can occur. The A.C.T.® automatical-

ly continues its journey as soon as the

obstacle has been removed.

This system is designed in full compli-

ance with current EU guidelines and has

been approved by the employers' liability

insurance association as providing the

necessary degree of safety from injury.

The safety system consists of a combi-

nation of active and passive sensors pro-

viding the maximum protection possible.

In travel direction, the entire pathway is

monitored by laser scanners which point

in the desired direction when moving

around corners and bends.

The area scanned is divided into two

zones. When an obstacle is detected, at

first only the speed is reduced. As soon

as the obstacle enters the �critical� sec-

ond zone right in front, the vehicle is

stopped.

In addition to the scanners, pressure

strips are mounted on the vehicle just

above the floor. The vehicle also stops

when these make contact with an object

in its path.

The chassis design is another important

factor permitting the flexible use of the

A.C.T.® in existing plant layouts.

The vehicle is fitted with four steerable

heavy-duty wheel sets. These allow it to

negotiate very sharp bends and to turn

virtually on the spot.

Each of the wheel sets is mounted on its

own articulated bearing. The chassis is

also mounted on a three-point bearing

which means that the load is always

evenly distributed.

In order to avoid costly modifications of

travel paths, one of the high design pri-

orities was to keep the specific floor

pressure as low as possible.

For this reason, heavy-duty wheel sets

were selected with twin tires and a dia-

meter of 600 mm.

The driven wheels are fitted with a differ-

ential gear system in order to keep the

load on the floor and wheels to a mini-

mum during steering maneuvers.

The motors used are standard three-

phase asynchronous motors controlled

by current inverters. This ensures opti-

mum control behavior, which, in combi-

nation with the chassis design, means

that the vehicle is always accurately po-

sitioned.

Power is provided by standard lead-cell

batteries with capacitive operation, i. e.

the batteries are run until they are almost

completely discharged and then re-

placed by fully charged ones.

While the second battery then remains in

the vehicle for the next eight hours (ap-

proximately), the discharged battery is

re-charged at the special re-charging

station.

This procedure means that the downtime

is reduced to about ten minutes per shift

and the vehicle is available for transport

operations around the clock.

The charge status of the battery is moni-

tored continuously, and when a certain

threshold value is reached, the vehicle

travels automatically to the battery-re-

placement point and docks in.

The battery is then removed automatical-

ly and replaced by a fresh one.

Capacitive battery operation means that

significantly more transport operations

can be executed by one vehicle than if

the battery were partially re-charged

whenever required. This would mean

that the vehicle would have to remain at

the charging station until the charging

process was completed. These relatively

short but frequent intervals add up to a

considerable period of downtime in the

course of a day, thereby markedly reduc-

ing the efficiency of the system as a

whole.

For this reason the SIEMAG designers

selected the substantially more economi-

cal solution of working with two batteries.

Batteries with a voltage of 288 V are

used to achieve maximum performance

and high vehicle speeds in the loaded

state.

This concept makes it possible to

achieve high efficiencies at low current

values and consequently high control re-

serves with the inverters, which are nec-

essary for good movement dynamics.

At Hydro Aluminium in Hamburg, Ger-

many, all the coil-transport operations in

the plant buildings were previously

carried out by fork-lift trucks and the coils

were stored in several small stores be-

tween the machines.

Due to the large number of manual oper-

ations involved, seamless, systematic

material tracking was virtually impos-

sible.

The next coils to be rolled were sum-

moned simply by calling to the fork-lift

driver.

In addition to this, a modernization pro-

gram carried out in 2002 resulted in an

increase in production of around one

third.

In order to make logistics simpler and

more predictable, it was decided to store

all the coils in a central high-bay store

and use an A.C.T.® system for the trans-

port operations.

Through the introduction of the A.C.T.®

system, the flow of material became fully

transparent; the position of each individ-

ual coil is now known at all times.

The coil movements are planned in ad-

vance with the result that the right coils

are always delivered to the right machine

at the right time.

Another serious disadvantage of trans-

porting coils "manually" by fork-lift truck

and crane was also eliminated by the

introduction of the A.C.T.® system. Coil

damage in transit was cut down to al-

most zero which naturally meant a sub-

stantial improvement in product quality.

Each of the five A.C.T.® vehicles oper-

ated by Hydro Aluminium has meanwhile

covered a total of about 50,000 km and

transported more than 40,000 coils.

Apart from normal maintenance work,

none of the larger parts have been re-

placed so far. Even the original Vulkollan

tires are still in use, although consider-

able doubt was initially expressed by the

customer here due to the aggressive

nature of the rolling oil.

The first large replacement operation is

now becoming due because the bat-

teries are exhausted after a total of

1,500 charging cycles. However, this op-

eration was planned in advance since it

was known that the batteries are only

designed for 1,200 charges.

After more than four years in operation,

the results obtained have fulfilled even

the most optimistic predictions.


SIEMAG A.C.T.® � Automatic Coil Transporter

Disadvantages of transporting coils by crane or

fork-lift truck


▬ Coil pick-up from floor, turnstiles, continuous conveyors or coil rests

▬ Max. payload 35,000 kg

▬ Integration in plants without modification of existing machinery

▬ Flexible traveling course, modifiable at any time; free navigation with laser

▬ No enclosed travel path required

▬ Chassis characteristics:

max. gradient: ±2 %

max. single obstacle: ±35 mm




Switch plates Reflective

sensor

Emergency

stop

buttons

Rotating beacon

Obstacle

detection

Full perimeter

mechanical

buffersVirtual

buffers

Safety devices on the SIEMAG A.C.T.®


Dead reckoning (DR) navigation Laser triangulation

Wheel 2 Wheel 1

Shaft encoderShaft encoder

Incremental

position encoder

Incremental

position encoder


Vehicle navigation



Four-wheel steering with twin tires and differential gears

▬ Extremely high maneuverability

▬ Travel in any direction possible

▬ Tight turning radii

▬ Exact positioning

▬ Safe load handling

▬ Low forces on wheel and floor

▬ Low wear on wheel and floor

A.C.T.® � Chassis concept � Main features


0

50

100

150

200

250

6 12 18 24

Coils

0

Time [h]

Battery operation with intermediate charging


15 min 18 min 15 min

Battery charging

Effect of battery concept on transport efficiency


0

50

100

150

200

250

6 12 18 24

Coils

0

Time [h]

Battery operation with battery replacement


15 min 8h8h

Battery replacement



0

50

100

150

200

250

6 12 18 24

Coils

0

Time [h]

Comparison of concepts


Battery charging

80 coils

SIEMAG A.C.T .®

Battery change

220 coils




▬ High power possible for high speed and

acceleration, even in loaded state

▬ Same power for significantly less current

▬ Lower cable diameter

▬ Standard asynchronous motors usable

▬ High control reserve of power

inverters gives improved travel

dynamics

▬ Higher degree of efficiency

▬ High life span

Effect of supply voltage on current

0,0

25,0

50,0

75,0

100,0

125,0

0 50 100 150 200 250 300 350 400 450 500 550

Current [A]

Power[KW]

288 V voltage (A.C.T.®) 80 V voltage

Advantages of higher battery voltage



▬ Capacitive operation

▬ Lead-acid battery

▬ Automatic battery

replacement

▬ 288 V battery voltage

Battery and battery replacement


0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Months

Costs A.C.T.®

Labor costs

Improvement

in quality

Savings

in total

Calculation basis:

Costs A.C.T.®: Investment costs plus operating expenses

(e. g. energy, maintenance, staff)

Saving of labor costs: Five persons for three-shift operation per vehicle

Improved quality: 40 kg less damaged material per 20-t coil


A.C.T.® � Profitability calculation


HRM � HBS:

200 m, 8 c/h

ANNEALING � HBS:

150 m, 3 + 3 c/h

CRM 2 � HBS:

50 m, 4 + 4 c/h

FINISHING � HBS:

70 m, 3 + 11 c/h

CRM 1 � HBS:

70 m, 16 + 16 c/h


Material flow at Hydro Aluminium, Hamburg/Germany



Hydro Aluminium, Hamburg/Germany



Operating data :

▬ Operating hours per A.C.T.®: approx. 4,800 h/year

▬ Average cycle data per transport operation: 7 min, 260 m

▬ Number of transport operations per A.C.T.®: approx. 41,700 year

▬ Distance covered per A.C.T.®: approx. 11,000 km year

▬ Operating time so far: approx. 4.5 years

▬ Total distance covered per A.C.T.®: approx. 50,000 km

Maintenance/wear:

▬ Replacement of friction bearings and regrinding of horizontal

guides during maintenance work

▬ Replacement of traction batteries after approx. 4.5 years

at a maximum of 1,544 charging cycles

(Design: 4.48 years at 1,200 nominal charging cycles)

Operating experience



▬ High transport efficiency

▬ High availability through design

of all components specially for

rolling mills

▬ High flexibility

▬ Complete transparency

of material flow

▬ Reduction of coil damage

to virtually zero

▬ High profitability of overall

system

Main advantages of the SIEMAG A.C.T.®

SMS DEMAG AGCold Rolling Mills Division

Wiesenstrasse 30

57271 Hilchenbach, Germany

Phone: +49 (0) 2733 29-1800

Telefax: +49 (0) 2733 29-1782

E-mail: cold.mills@

sms-demag.com

Internet: www.sms-demag.com

MEETING your EXPECTATIONS

ME

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Sessio

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250/0

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WW

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anyStrip Processing Lines Division

Walder Strasse 51 – 53

40724 Hilden, Germany

Phone: +49 (0) 211 881-5100

Telefax: +49 (0) 211 881-5200

E-mail: strip.processing@

sms-demag.com

Internet: www.sms-demag.com

SIEMAG GMBH

Obere Industriestrasse 8

57250 Netphen, Germany

Phone: +49 (0) 2738 21-521

Telefax: +49 (0) 2738 21-591

E-mail: [email protected]

Internet: www.siemag.com

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