Improved Quality by

Electro Slag Re-melting (ESR)

ALD Vacuum Technologies High Tech is our Business

ALD Vacuum Technologies High Tech is our Business

Improved Quality by Electro Slag Re-melting

Table of Content

1. Introduction

2. Applications

3. Electro Slag Re-Melting, Principle

4. Metallurgy

5. Enhanced Properties

6. Economical View

7. Conclusion

Introduction

Since the 1960er years Electro Slag Re-melting (ESR) is used mainly in

the production of Nickel base alloys.

New requirements and demands on high grade steel makes this procedure for

steel production more and more important

Introduction

Since the 1960er years Electro Slag Re-melting (ESR) is used mainly in

the production of Nickel base alloys.

New requirements and demands on high grade steel makes this procedure for

steel production more and more important

Forging and/or

mechanical Shop

Vacuum

Degassing

(VD)

Ladle

Furnace

(LF)

Electro Arc

Furnace (EAF) Electro Slag

Re-melting

(ESR)

Vacuum Induction

Degassing (VID)

Ingot Casting Electrode

Casting

Introduction

0%

25%

50%

75%

100%

Nickel Alloys Tools Steeland High

Speed Steel

BearingSteel

StainlessSteel

OtheralloyedSteel

Nickel base Alloys 390.000 tons Tools & High Speed Steel 2.340.000 tons Bearing Steel 6.400.000 tons Stainless Steel 38.740.000 tons Other alloyed Steel 106.130.000 tons

Worldwide high alloyed steel and Nickel base alloy production was

in 2016 roughly 154 million tons distributed in following shares:

Share on re-melted Material

~ 4 million tons are re-melted

This share increases yearly

Source: SMR Premium GmbH

Application (some Samples)

Aerospace

discs, rings, blades, studs,

bolts, rivets, bearings

structural parts,

landing gears

Medical

stents,

pacemaker wires,

dental wires

Oil & Gas

tools, seals, fitting

safety valves,

pipe joints, flanges

Power

gas turbines blades

discs, shafts, bearings,

nuclear application

Tools

for extrusion & die casting

precision, coining

& forging tools

Transport / Automotive

injection parts

valves, bearings

turbo charger

Electro Slag Re-melting, Principle

liquid pool

tripping

water cooled

crucible/mould

Electrode

Refined Ingot

refining slag

AC

~

Self consuming electrode at the top

with ~80% diameter of the refined ingot

solidification

Built up the refined ingot from the bottom

AC power supply

Water cooled copper

Refining slag (CaF2, CaO, Al2O3, MgO)

Inert gas (Argon / Nitrogen)

Round and square ingots

Typical ingot weight from 0,35 – 150 tons

Metallurgy

Refining from inclusions

Elimination of voids

Refining from Sulphur

No pickup of Oxygen and Hydrogen

due to protective atmosphere

Increased homogenization of the

alloying elements

Improved micro structure of the ingot

Zero macro segregation

Improved material properties

increases the life-time of the

final products

Metallurgy

Source: Choudhury and co-workers

Globular Grain

in Hot Top Area

Dendritic Structure

in Center Section

Dendritic Structure

in Bottom Part

Ø 460mm

Increased Cleanliness

K1 value

Higher material yield

no shrinkage cavity as on conventional

casted ingots

Less dendrite arm spacing

No macro segregation

Homogenous element distribution

Improved and isotropic material

properties in longitudinal / transversal

Enhanced Properties

10

Carbon segregation measured

over the height of the ingot

(longitudinal)

Carb

on

co

nte

nt [%

]

Distance from surface [mm]

0.6

0.7

0.8

0.9

1

1.1

1.2

0 50 100 150 200 250

Carbon segregation measured

over cross section.

Ø = 465mm, transversal

Source: Choudhury and co-workers / ALD

1.4

1.5

1.6

1.7

1.8

0 10 20 30 40 50

ESR re-melted non re-melted

Enhanced Properties

Chromium segregation measured

over the cross section

transversal

Source: Choudhury and co-workers / Saarschmiede, Germany

Increase of the specific density

Distance from surface [%]

Chro

miu

m c

on

ten

t [%

]

7.80

7.81

7.82

7.83

7.84

7.85

7.86

1 2 3 4 5 6

Den

sity [g/c

m³]

Forging Ratio Fn/F1

ESR re-melted

non re-melted

Enhanced Properties

Source: Böhler Steel

Steel: Böhler N700 / DIN 1.4542 / 17-4ph / SUS630

C: 0,03% Cr: 15%, Nb: 0,3%, Ni 4,3%, Cu 3,3%

Cleanliness Values for certain steelmaking processes

Reduction of the inclusions

and scatter range by using

re-melting technologies

Economical View, Sample: Tool for Automotive

Melted

LF/VD VIM

Re-melted

ESR

Twice

re-melted ESR - VAR

Material Costs 1.460 € 2.290 € 3.090 €

Tool manufacturing costs 52.600 € 52.600 € 52.600 €

Total tool costs 54.060 € 54.890 € 55.690 €

Life time (number of cycles) 100.000 150.000 255.000

Specific costs 0,54 € 0,37 € 0,22 €

Source: Böhler Steel

Steel: SKD61, H13, 1.2344

Hardness: 44 – 46 HRC

Manufacturing costs [€uro]

Costs

/ c

ycle

[€

uro

]

0.00

0.20

0.40

0.60

52,000 53,000 54,000 55,000 56,000

0

200

400

600

800

1,000

1,200

0 200 400 600 800 1000

Economical View

Ingot ø [mm]

Me

lt r

ate

[k

g/h

]

Typical re-melt rates: ø Ingott

[mm]

Re-melt rate

[kg/h]

300 290 – 330

1.000 950 – 1.100

0 250 500 750 1000

Electro Slag Re-melting technology is a state of the art in today’s steel making.

The ESR process is used by major steel manufacturer worldwide.

New high demanding requests for physical and chemical properties

of steel require Electro Slag Re-melting technology.

Driving industries are automotive, aerospace and medical

ESR processes is beneficial for

bearing steel as well as for tool

and high speed steel.

The enhanced characteristics of

re-melted steel leads to higher

life time / cycles and reduces the

costs of a final products

Conclusion

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