International Journal of Research in Engineering and Innovation Vol-1, Issue-1 (2016), 34-40

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International Journal of Research in Engineering and Innovation (IJREI)
Home page http:// www.ijrei.com

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Stress Analysis of Angle Bar with Different Process Parameter in Hot

Rolling
Mudit Sharma1, Bashistha Kumar Kushwaha2
1M.E. Scholar, Department of Mechanical Engineering, NITTTR, Chandigarh, India
2
Department of Mechanical Engineering, Roorkee Engineering &Management Technology Institute, Shamli India
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Keywords Abstract
In hot rolling mill process the rollers is subjected to heating and cooling cycles with
Hot Rolling, Cold different processing parameter. This nature of heat and processing parameter found some
Rolling, Cracks, cracks, wear and tear in hot roller. In this work, the study of existing process was done to
Coefficient of Friction, find the root cause of the cracks in roller mills. The analysis of the rolling process was
Stress, Strain done and results obtained in terms of equivalent stress and effective plastic strain. It has
been found that mill speed and friction coefficient are the two major factors that
significantly affect the quality of rolling products. Lower value of friction coefficient
requires that number of mill passes be increased. Higher value of friction coefficient
increases the sticking between rollers and the incoming metal leading to defects in steel
angle bar. © 2016 ijrei.com. All rights reserved
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1. Introduction

The sizing press followed by horizontal rolling is more display rising trend, uneven deformation of flange lead to
efficient in width reduction than deformation by a heavy more complex temperature distribution, there is certain
edger mill followed by horizontal rolling. The finite- correlation between equivalent plastic stress and
element analysis results for the deformation of a slab also temperature distributions, increasing of equivalent plastic
show reasonable agreement with measurements from an stress as the temperature increases, research results can
actual mill test, and from physical modelling experiments provide theoretical basis for rolling regulations and
[1]. The effects of process parameters such as the cooling reference of the production of hot rolling for H-beam [4].
condition of the work-rolls, the rolling speed, and the roll The vertical roller mill 3-D model established in Pro/E is
metal interfacial heat-transfer coefficient on the imported into ADAMS through the data interactive
temperature distributions in the work-rolls as well as in the software Mech/pro to analyze its stress, and then carry out
rolling metal. The comparison between the model the FEA of the model loaded in ANSYS. After Comparing
predictions and experimental results shows the validity of with the material yield limit, the both stresses are
the proposed model [2]. The rapid development of reasonable which will meet the demand of design. This co-
computer technology and the improvement of general finite simulation method provides a reliable basis for vertical
element analysis software, especially with the development roller mill design and can also be applied to other
of parallel computing technique, it has become possible to mechanical system design process [7]. A coupled thermo-
analyze cold strip rolling process and calculate the strip mechanical finite element method computation on steel
deformation with 3-D finite element contact model of rolls pipe rolling process, gets the residual stress and strain
and strip [3]. The temperature of H-beam was a downward change rule in the rolling process. They analyzed the
trend in the hot rolling process, however, local temperature influence of roller spacing and velocity parameters on

Corresponding Author: Mudit Sharma 34

Email address: good.mudit@gmail.com
 Mudit Sharma et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 1 (2016), 34-40

residual stress and strain, which provides a reliable theory finite-element models, which are incorporated into an
basis for improving the performance of hot rolling seamless iterative-solution procedure to deal with the
steel pipe and the optimization of rolling technological interdependence between the thermo-mechanical behavior
parameters [8]. The roll cross angle, rolling press quantity, of the strip and that of the work roll. However, the model
intersection position and rolling speed can change the size addressed only a part of roll wear–related problems,
of the axial force, axial forces may float small by the leaving the rest for future works [19]. They used finite
pressing ratio increases, lager by rolling speed increases, element analysis technique to investigate behavior of rolls
bigger by adding more far intersection point position, This related to bending, shifting and levelling. The effective
conclusions have realistic significance in cross rolling utilization of these methods, leads improvisation of the
schedule making, and provide basis theory reducing rolling flatness in the cold rolled sheet. Apart from the profile of
axial force [9]. The ring can approximately maintain its sheet, the shape was also significantly affected by the
round shape at the initial rolling period, when the process vibrations developed in mill housing [20]. The developed
is entering the medium period, the roundness of the ring procedure for the simulation of the hot rolling process.
becomes worse, and it tends to be improved at the final They stated that rolling is a 3D process but using the
rolling period. A series of ring rolling experiments were generalized plane strain method, the real 3D problem can
conducted. So the reliability of the finite element model of be solved using a 2D Finite Element Model, saving an
the vertical hot ring rolling process with measurement and important computing time [21]. FEM software are able to
control was validated [10]. The formation of edge defects describe the kinetics of recrystallization during the process,
in hot strips, resulting from slab corner cracks generated in taking into consideration grain size refinement and grain
continuous casting. They developed a model-based growth. By incorporating such mathematical models, it is
concepts for the identification of such initial slab cracks. possible to predict the formation process as a whole,
To accomplish this task a systematic finite element tool including the final microstructure obtained for the forged
Deform-3D was utilized. The numerical results clearly part, allowing process optimization that focuses on a
pointed out the significant morphological changes of the higher-quality final product [22]. They developed a
cracks during rolling and afford valuable indications for a computer system to detect shape defects in the rolled
deeper understanding of the underlying process details product and determined the degree of deformation of metal
[11]. A two dimensional elastic plastic model was used to at the design stage, which allows the initial plans to
simulate the cold rolling of thick strip. They found the approximate the final design as closely as possible. So this
speed and diameter of rolls have influence on the quality of system is very helpful for future researchers, would make
rolling products [14]. The mechanical properties of high it possible to avoid having to perform a large number of
strength steel and mild steel at elevated temperatures. They costly and time-consuming commercial trials and to predict
found that yield strength, tensile strength and elastic the defects might be formed in the rolled product [23].The
modulus of steels at elevated temperatures decreases [15]. variation of the blade cross-section, the deformation stress
The investigating the mechanism of thermal crack growth and strain of the work-piece keep changing during the
while taking into account the complex thermal and rolling process and the conventional rolling theory is no
mechanical interactions during the rolling process. They longer valid. The complexity and diversity of the blade
utilized the concepts of FEM for the estimation of rolls life, cross-section determine it impossible to establish a
from the perspective of thermal fatigue. Their work universal theoretical model for the rolling process
described the methodology of predicting thermal fatigue [24].Finite element method is reliable and versatile
crack growth using innovative modelling techniques and analytical method that avoids bold hypothesis, which are
they highlights the importance to the operating conditions often involved in the classical methods such as the slab
[16]. The accuracy of the FE model was analysed through method or the energy method [25]. In this work the
a dual comparison by geometrical and by physical aspects. effective stress and strain is carried out in steel angle bar
The effectiveness of a new numerical subroutine was tested during hot rolling operation with optimum process
by a comparison with experimental values acquired from parameter for prevent the edge crack in angle bar.
an industrial plant tool wear, the author characterized the
extent of the tool wear by wear depth. Twenty points were
used to measure tool wear depth with different area
reduction, forming angle, and stretching angle [17].There
was good agreement between experimental results and the
simulation in terms of wear and rolling friction under
different operating conditions. The analysis of disc-disc
interaction has been presented by using FEM technique.
However this work gives rise to thoughts about possible
applications in various fields [18]. The finite element Figure 1: Edge Crack
model for the prediction of the steady-state thermo-
mechanical behaviour of the roll-strip system and of roll
life in hot strip rolling. The model was comprised of basic

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 Mudit Sharma et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 1 (2016), 34-40

2. Results and Discussion

The effective stress and strain is carried out in steel angle
bar during hot rolling operation with optimum process
parameter for prevent the edge crack in angle bar. The
diameter of the rollers and temperature of the material were
not changed as per industry requirement. Also limit of mill
speed was taken 110 rpm.
The simulation results were obtained in the terms of
effective plastic strain and effective stress distribution. The
acceptance criteria of plastic strain is 0.5 in hot rolling [26].
So the plastic strain value exceeds this limit then it will lead
edge cracks in steel angle bar.
(a)

(a)

(b)

(b)

Figure 3: Effective Plastic Strain Distribution in Angle Bar at

N=110 rpm,(a) µ=0.20 (b) µ=0.25 (c) µ=0.30

In this work the ingot and rollers assembly was subjected

to mill speed of 105 and 110 rpm with friction coefficient
0.20, 0.25 and 0.30. The minimum effective plastic strain
was produced 0.5892 at N=105 rpm with friction
coefficient 0.20 and maximum effective plastic strain was
produced 0.8864 at N=110 rpm (µ=0.20)

(c)

Figure 2: Effective Plastic Strain Distribution in Angle Bar at

N=105 rpm, µ=0.20 (b) µ=0.25 (c) µ=0.30

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 Mudit Sharma et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 1 (2016), 34-40

(a) (a)

(b)
(b)

(c)
(c) Figure 5: Effective Stress Distribution in Angle Bar at N=105
Figure 4: Effective Stress Distribution in Angle Bar at N=105 rpm, at µ=0.20 (b) µ=0.25 (c) µ=0.30
rpm,(a) µ=0.20 (b) µ=0.25 (c) µ=0.30

The ingot and rollers assembly was subjected to mill speed

of 90 rpm, 95 rpm and 100 rpm with friction coefficient
0.20, 0.25 and 0.30. The maximum effective stress was
produced 598.48 MPa at N=105 rpm with friction
coefficient 0.30 and minimum effective plastic strain was
produced 528.89 MPa at N=110 rpm (µ=0.30)

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 Mudit Sharma et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 1 (2016), 34-40

(a) (a)

(b) (b)

(c) (c)
Figure 6: Effective Plastic Strain Variation with Mill Speed at Figure 7: Effective Stress Variation with Mill Speed at
(a) µ=0.20 (b) µ=0.25 (c) µ=0.30 µ=0.20 (b) µ=0.25 (c) µ=0.30

The effective plastic strain variation leads to some

interesting observation. The plastic strain is increased or The effective stress variation also leads to some interesting
decreased between mill speeds 90 to 105 rpm at all observation in hot rolling mill operation. The stress
coefficient of friction, but after mill speed 105 rpm, the increased and decreased throughout the rolling mill speed,
plastic strain always increased rapidly. and the maximum stress was observed at 598.48 MPa at
N=105 rpm with friction coefficient 0.30 and minimum
effective plastic strain was produced 528.89 MPa at N=110
rpm (µ=0.30)

3. Conclusions
The analysis of the rolling process was done and results
obtained in terms of equivalent stress and effective plastic
strain. The effects of the friction on the rolling of steel

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 Mudit Sharma et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 1 (2016), 34-40

angle bar were studied for friction coefficient values of Variations and Process Control Method of Vertical
0.20 to 0.30. The simulation results indicate that the value Hot ring Rolling’’, International Journal of Advance
of friction coefficient affects the effective stress and Manufacturing Technology, 2014, pp. 389-398.
effective plastic strain. The minimum effective plastic [10] Huang Chang-qing, DENG Hua, DIAO Jin-peng and
strain was produced 0.5892 at N=105 rpm with friction HU Xing-hua, “Numerical Simulation of Aluminum
coefficient 0.20 and maximum effective plastic strain was Alloy Hot Rolling using DEFORM-3D’’. International
produced 0.8864 at N=110 rpm (µ=0.20), whereas the Conference on Computer Science and Automation
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N=105 rpm with friction coefficient 0.30 and minimum
[11] Alexander Kainz, Sergiu Ilie, Erik Parteder and Klaus
effective plastic strain was produced 528.89 MPa at N=110
Zeman,‘‘From Slab Corner Cracks to Edge-Defects in
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Hot Rolled Strip, Experimental and Numerical
Investigations’’, Steel Research International, Vol.79,
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