Modeling and Optimization of Rolling Process: A Multi-Objective Approach

2020 ◽  
Vol 19 (02) ◽  
pp. 343-364
Author(s):  
S. Panda ◽  
S. N. Panda
Keyword(s):  
Cold Rolling ◽  
Film Thickness ◽  
Temperature Rise ◽  
High Speed ◽  
Rolling Process ◽  
Response Analysis ◽  
Strip Rolling ◽  
Multi Objective ◽  
Inlet Zone ◽  
Cold Strip Rolling

In a high-speed cold strip rolling process, it is necessary to optimize the process parameters for improved quality in the product. In this study, two separate multi-objective optimization problems for a cold rolling process are formulated. The objectives in one of the cases are minimum isothermal film thickness and film temperature rise in the inlet zone and in another case it is minimum thermal film thickness and film temperature rise in the inlet zone. Particle swarm optimization algorithm has been used for solving the optimization problem. The key input parameters for the cold rolling process are identified and prioritized through the convergence study and the coefficient of variation analysis. A response analysis is performed on the critical input variables. This study assists the process engineer to understand the lubrication in cold strip rolling at high speed and select an appropriate lubricant for a given combination of strip and rolls.

Experimental and Numerical Study of Emulsion Lubricated Strip Rolling

2005 ◽  
Author(s):  
P. B. Kosasih ◽  
A. K. Tieu
Keyword(s):  
Film Thickness ◽  
Numerical Study ◽  
Rolling Process ◽  
Work Zone ◽  
Contact Ratio ◽  
Strip Rolling ◽  
Two Phase ◽  
Oil Concentration ◽  
Mixed Film ◽  
Inlet Zone

An experimental and numerical study of cold rolling lubricated by O/W emulsion has been carried out. The experimental measurements are compared to the computed results from the numerical scheme developed by the authors. The scheme, which is based on two-phase lubricant model, is able to calculate oil concentration at any point within the inlet zone and work zone, rolling pressure, film thickness, and fractional contact ratio associated with strip rolling under mixed film lubrication at different rolling speed. The study encompassed extensive mixed film regime for speed, S ranges from 10−5 to 10−1, and supply oil concentration level λds ranges from 1% to 10%, and oil droplet size ranges from Ds from 5 to 20. The numerical results show the occurrence of moderate oil concentration increase in the inlet zone followed by a sharp one at the beginning of the work zone. The effect of the concentration process is predominantly seen in the film thickness and the lubricant pressure whilst its effect on the total pressure is less pronounced. The analysis of the results suggests that it is possible to lower the emulsion oil concentration without detrimental effects on the rolling process and indeed use this principle to control the outlet lubricant film thickness.

Effect of Lubricant Scarcity on the Film Formation in an Inlet Zone During High Speed Cold Rolling Process

2007 ◽  
Author(s):  
Prahlad Singh ◽  
R. K. Pandey ◽  
Yogendra Nath
Keyword(s):  
Cold Rolling ◽  
High Speed ◽  
Heat Dissipation ◽  
Film Formation ◽  
Rolling Process ◽  
Lubricating Oil ◽  
Lubricating Film ◽  
Viscous Heat ◽  
Inlet Zone ◽  
Reduced Temperature

Effective lubrication during the cold rolling is vital in achieving desirable tolerance and surface quality over the metallic sheets. However, in the process of cold rolling, it has been established that the lubricant’s viscosity drastically reduces (viscosity thinning) due to huge viscous heat dissipation in the lubricating film at the elevated rolling speeds. Thinning of lubricant viscosity increases the escaping tendency of the lubricant from the inlet zone. Thus, scarcity (starvation) of lubricant prevails in the inlet zone of roll and strip interface. Based on the present investigation, it is observed that the existence of starvation seems to be beneficial in terms of reduced temperature rise and less quantity of lubricating oil required provided there is a continuous film at the strip-roll interface.

Thermal effect on the film thickness in high-speed lubricated cold rolling of a strip—an inlet zone analysis

2003 ◽  
Vol 217 (2) ◽  
pp. 155-166 ◽  
Author(s):  
M. K. Ghosh ◽  
R. K. Pandey ◽  
P Singh
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Cold Rolling ◽  
Film Thickness ◽  
Difference Method ◽  
High Speed ◽  
Energy Equation ◽  
Temperature Variations ◽  
The Finite Difference Method ◽  
Inlet Zone

A thermal analysis of hydrodynamic lubrication of high-speed cold rolling of strips in the inlet zone has been made to estimate the film thickness in the contact region. The piezoviscous effect, which would be significant in the case of heavy-duty rolling when a large reduction in the thickness of the strip takes place during the rolling process, has been incorporated using Roelands' viscosity model. The generalized Reynolds equation in the inlet zone has been solved using the finite difference method to determine the pressure distribution. Temperature variations across the film have been expressed using Legendre's polynomial at Lobatto points while solving the energy equation. Temperature variations along the film were determined using the finite difference method by solving the energy equation. The results for the film thickness-temperature profile in the inlet zone have been estimated for high-speed rolling of the strip (up to 50m/s) with and without sliding for heavy reduction in thickness of the strip. Significant reduction in the film thickness due to the thermal effect has been found.

Friction and Forward Slip in High-Speed Cold Rolling Process of Aluminum Alloys

2012 ◽  
Vol 229-231 ◽  
pp. 361-364 ◽  
Author(s):  
Qiao Yi Wang ◽  
Yao Zhu ◽  
Yong Zhao
Keyword(s):  
Cold Rolling ◽  
Coefficient Of Friction ◽  
High Speed ◽  
Rolling Process ◽  
Forward Slip ◽  
Working Process ◽  
Strip Rolling ◽  
Varying Coefficient ◽  
The Coefficient Of Friction ◽  
Prime Objective

Effects of process parameters on friction in cold strip rolling process have been studied in this article. The prime objective is to examine the major parameters affecting the metal working process. A varying coefficient of friction through the roll contact arc has been determined. A few formulae, commonly used to predict the coefficient of friction from forward slip measurements of a rolling process, have been evaluated according to forward slip measurements and coefficient of friction data. Essentially, this article bridges the industrial constant coefficient friction approach from forward slip measurements with the academic varying coefficient of friction strategy. A systems analysis has been made regarding the effects of potentially important parameters on friction in cold rolling. Based on this analysis, the effects of a few parameters have been identified of most importance.

Hydrodynamic Model for Cold Strip Rolling

1967 ◽  
Vol 182 (1) ◽  
pp. 153-162 ◽  
Author(s):  
D. S. Bedi ◽  
M. J. Hillier
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Entropy Production ◽  
Coefficient Of Friction ◽  
Hydrodynamic Model ◽  
Reynolds Equation ◽  
Viscous Friction ◽  
Strip Rolling ◽  
Roll Pressure ◽  
Cold Strip Rolling

The theory of rolling is modified to allow calculation of a hydrodynamic film thickness and viscous friction coefficient using Reynolds equation for the lubricant. Calculations are made for the case where the fluid film covers the arc of contact. The film thickness is assumed uniform and is determined by the principle of minimum rate of entropy production. It is shown that the apparent coefficient of friction varies significantly over the arc of contact. At small reductions the roll load tends to decrease with speed of rolling, while at high reductions the load tends to increase. The point of maximum roll pressure does not coincide with the neutral plane; and under certain rolling conditions there may be no maximum in the pressure over the arc of contact.

Effect of a Surface Film on the Surface Temperature of a Rotating Cylinder

1986 ◽  
Vol 108 (1) ◽  
pp. 92-97 ◽  
Author(s):  
B. Gecim ◽  
W. O. Winer
Keyword(s):  
Thermal Properties ◽  
Heat Source ◽  
Film Thickness ◽  
Surface Temperature ◽  
Temperature Rise ◽  
High Speed ◽  
Integral Transform ◽  
Heat Conduction Problem ◽  
Surface Film ◽  
Layer Effect

Solution to the steady heat conduction problem of a rotating layered cylinder is presented. The governing differential equations (for the film and the substrate) are solved by using an integral transform technique. It is shown that the presence of a surface film measured in micrometers can substantially change the level of the surface temperature. The effect of the surface film on the surface temperature depends on: respective thermal properties of the film and the substrate; relative surface speed; heat source (contact) size; and surface film thickness. However, the range in which the effect of the film on the surface temperature is dependent on these parameters is limited. Outside this range (i.e., thin film/low speed or thick film/high speed) the surface temperature rise is determined by the thermal properties of the substrate, or by the properties of the film alone, respectively. Hence, outside this range, a further change in the film thickness does not influence the surface temperature rise. Dimensionless plots showing the change in surface temperature rise as a function of material thermal properties, surface speed, heat source size, and film thickness are presented. Behavior for specific material combinations are also presented. The present information can be utilized to predict the layer effect on the partition of heat between the layered cylinders.

The Influence of Elastic Deformation of the Roll and the Sheet in a Hydrodynamically Lubricated Cold Rolling Process

1995 ◽  
Vol 117 (3) ◽  
pp. 468-475 ◽  
Author(s):  
P. M. Lugt ◽  
W. E. ten Napel
Keyword(s):  
Cold Rolling ◽  
Film Thickness ◽  
Elastic Deformation ◽  
Hydrodynamic Lubrication ◽  
Rolling Process ◽  
Process Conditions ◽  
Shear Stresses ◽  
Strip Surface ◽  
Roll Flattening ◽  
Dense Grid

A model has been developed for simulating hydrodynamic lubrication in cold rolling. Both Roelands’ and Barus’ viscosity-pressure relations have been applied. Thermal effects regarding heat development caused by plastic deformation as well as work hardening have been included. Furthermore, elastic deformation of the surfaces has fully been incorporated in the model, i.e., elastic deformation of both the strip and the rolls. The governing equations have been solved numerically throughout the entire contact i.e. inlet, work and outlet zone using a very dense grid. Multigrid techniques have been used to solve the equations. It will be shown here that roll flattening has a significant effect on film thickness. However, elastic deformation of the strip material in the inlet region even has a more pronounced effect on film thickness and thus on several process conditions. Furthermore, it is shown that the choice of the viscosity-pressure parameter is limited. Higher values of this parameter cause excessive shear stresses on the strip surface.

scholarly journals Comprehensive Analysis of Metal Deformation Law Based on Numerical Simulation of Cold Rolling Process

2020 ◽  
Author(s):  
Zhu-Wen Yan ◽  
Bao-Sheng Wang ◽  
He-Nan Bu ◽  
Hao Li ◽  
Lei Hong ◽  
...  
Keyword(s):  
Finite Element ◽  
Cold Rolling ◽  
Finite Element Model ◽  
Equivalent Stress ◽  
Element Model ◽  
Work Roll ◽  
Rolling Process ◽  
Efficiency Coefficient ◽  
Strip Rolling ◽  
Research Results

Abstract Through taking the cold rolling process as the research object, the three-dimensional finite element model of the strip rolling process is established by using ANSYS/LS-DYNA software. The simulation results of the finite element model have a good fit with the actual production data. The rolling process is dynamically simulated, and the distribution curves of important rolling parameters such as equivalent stress, control efficiency coefficient, transverse rolling pressure, lateral thickness and work roll deflection is obtained. The research results of this paper have strong practicability for the process control of cold strip rolling mill. The research results have certain guiding significance for the development and optimization of the rolling control system.

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