FEM analysis of rolling process

FEM ANALYSISOF

ROLLING PROCESS

DEPARTMENT OF MECHANICAL ENGINEERING, CKPCET

Prepared by:

Varun V. Joshi (100093119001)

Aditya A. Patel (090090119003)

Chetan K. Anghan (090090119006)

Abhishek A. Mukherjee (090090119010)

Guided By :

Prof. Chaitanya K. Desai

Company :

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When metal passes through rolls, metal starts deforming and stress builds up at

arc of contact. There is residual stress remaining within the rolled product post

rolling.

Finite Element Method (FEM) Analysis is a method of analysis for numerical

solution of field problems. A field problem requires that we determine spatial

distribution of one or more dependent variables.

In our project, we are concerned with cold rolling process only and intend to

obtain the influence of various parameters such as Co-efficient of friction, Plate

feed speed and Roller Velocity on outputs like Von-Mises Stress, PEEQ &

Pressure, whose distributions have already been obtained through different

inputs using FEM software.

INTRODUCTION

FEM ANALYSIS OF ROLLING PROCESS

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ESSAR Steel, Hazira is a name renowned within the Rolling Industry.

It has the most vast amount of rolling facilities in the country and the various

complexes that are involved in the Rolling process are as follows :

Iron Making Facility

Hot Roll Mill

Cold Roll Mill

In the Cold Roll Mill Complex we observed the following types of Roll Mills

5-Stand Tandem Mill

4-High Single Pass Reversing Mill

COMPANY PROFILE


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LITERATURE REVIEW


Sr. No TITLE YOP

1SIMULATION OF PLANE-STRAIN ROLLING BY THE RIGID-PLASTIC FINITE

ELEMENT METHOD1981

2SIMULATION OF THE COLD ROLLING OF STRIP USING AN ELASTIC-

PLASTIC FINITE ELEMENT TECHNIQUE1985

3A RIGID-PLASTIC FINITE ELEMENT ANALYSIS OF TEMPER ROLLING

PROCESS2002

4ELASTO-PLASTIC FINITE ELEMENT SIMULATION OF A SYMMETRICAL

PLATE ROLLING USING AN ALE APPROACH2006

5INVESTIGATION OF INFLUENCE PARAMETERS ON THE HOT ROLLING

PROCESS USING FINITE ELEMENT METHOD2010

6 ROLLING MILL ROLL DESIGN 2003

7NON LINEAR FINITE ELEMENT METHOD SIMULATION AND MODELING OF

COLD AND HOT ROLLING PROCESSES.2007

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CLASSICAL APPROACH TO ROLLING


The formulation of the problem based on classic approach is done by SLAB

METHOD.

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FINITE ELEMENT ANALYSIS


Before we proceed to the formulation of problems and their simulation there are

some basic concepts that one should be familiar with:

QUASI-STATIC SIMULATIONS USING EXPLICIT DYNAMICS

MASS SCALING

ALE method

Element: CPE4R(4 node bilinear plain strain , quadrilateral , reduced

integration, hourglass control)

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FEA ROLLING ASSUMPTIONS


These are the assumptions that we have taken in our simulations:

The arc of contact between the rolls and the metal is a part of a circle.

The coefficient of friction, µ, is constant in simulation, but in actual

scenario, µ varies along the arc of contact.

The metal is considered to deform plastically during rolling.

The volume of metal is constant before and after rolling. In actual scenario,

the volume might decrease a little bit due to close-up of pores.

The velocity of the rolls is assumed to be constant.

The metal only extends in the rolling direction and no extension in the

width of the material.

The cross sectional area normal to the rolling direction is not distorted.

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INITIAL BASIC SIMULATION MODEL


When we went to the industry, they asked us to formulate a basic simulation

model. This was the simulation model we had formed.

2D Deformable plate

Analytical Rigid Wire

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10



Reference

Point

Point of Instance

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Roller Fixed

Upward Movement

restricted

Plate Feed

Velocity

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This is the ALE meshed part. Element used is CPE4R. Total

no. of elements is 460.

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IBSM - SOLUTION


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SHEET SIMULATION MODEL


Based on our Initial Basic Simulation Model, the industry provided us with the

following data.

Length : 1500 mm

Initial Sheet Thickness : 5 mm

Final Sheet Thickness : 4 mm

Sheet Feed Velocity : 1.5 m/s

Roller Diameter : 380 mm

Roller Velocity: 200 MPM (20 Rad/s)

Initial Material Hardness : 50-60 HRB

Post-Rolling Material Hardness : 90 HRB

Post-Annealing Material Hardness : 60 HRB

c

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The further steps are to be carried out in a similar manner to the way the plate

problem was formulated.

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SHEET – VMS DISTRIBUTION


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SHEET – PEEQ DISTRIBUTION


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SHEET - PRESSURE DISTRIBUTION


-50

0

50

100

150

200

250

300

350

400

450

0 2.3 4.53 6.7 8.8 11 13.13 15.27 17.42 19.55 21.73 23.89 26.07 28.28 30.48 32.7

Str

ess

True distance along path

Pressure Distribution along Arc of Contact

Pressure

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VARIATION IN RESIDUAL STRESSES

As seen in earlier slides, we obtained the Von-Mises Stress distribution.

Once the Roll force is removed, the stress remaining in the Sheet may be

considered as Residual Stress.

Now we proceed to see the variation in the residual stresses based on the

following parameters:

•Co-efficient of friction f

•Plate Feed Velocity Vp

•Roller Velocity Vr


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CO-EFFICIENT OF FRICTION f

150

155

160

165

170

175

180

185

190

195

200

0.2 0.25 0.3 0.35 0.4 0.45

Vo

n M

ises

/ R

esid

ua

l S

tres

ses

Co-Efficient of Friction f

Residual Stress v/s Co-eff of Friction f

Residual Stresses

Residual stresses initially increase with increase in Co-efficient of

Friction f upto value = 0.35 and then decreases


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PLATE FEED VELOCITY VP

Residual stresses decreases with increase in plate feed velocity Vp upto

value = 1.5 and then has a sudden increase.

0

50

100

150

200

0.25 0.5 0.75 1.25 1.5 1.75

Vo

n-M

ises / R

esid

ual

Str

esses

Plate Feed Velocity Vp

Residual Stresses v/s Vp

Residual Stresses


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ROLLER VELOCITY VR

Residual stresses remains more or less constant with increase in plate

feed velocity Vp, but experiences a sudden drop at value = 9 and then

again follows the earlier established trend.

130

135

140

145

150

155

7 8 9 9.5 10 10.5

Vo

n-M

ises / R

esid

ual

Str

esses

Velocity of Roller Vr

Residual Stresses v/s VR

Residual Stresses


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OPTIMUM PARAMETERS

Based on all the above graphs, we may conclude that there is a

most optimum combination of parameters which would result in

an overall reduction in the residual stresses.

Co-efficient of Friction f = 0.45

Velocity of Plate Feed VP = 1.5 m/s

Velocity of Roller VR = 9 rad/s


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SCOPE OF FUTURE WORK


When we formulated the shell problem, in the job analysis stage we found

excessive deformation in the roller outer surface and the plate. This was

perhaps due to incorrect load and boundary conditions that we had applied. In

spite of our best efforts, we were unable to remove and eliminate the error and

hence there remains a scope for future work in that direction.

THANK YOU

FEM analysis of rolling process

Engineering

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