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.

A Thermal Hydrodynamic Lubrication Analysis for Entrained Film Thickness in Cold Strip Rolling

1990 ◽  
Vol 112 (1) ◽  
pp. 128-134 ◽  
Author(s):  
K. Yuan ◽  
B. C. Chern
Keyword(s):  
Film Thickness ◽  
Reynolds Equation ◽  
Hydrodynamic Lubrication ◽  
Equation Model ◽  
Temperature Dependent ◽  
Strip Rolling ◽  
Temperature Dependent Viscosity ◽  
Approximate Models ◽  
Dependent Viscosity ◽  
Cold Strip Rolling

A thermal hydrodynamic lubrication analysis which takes account of temperature-dependent viscosity variation along as well as across the film thickness is developed for the entrained film thickness in cold strip rolling using generalized Reynolds equation (Dowson, 1962). The results are compared with that of the two approximate models (i.e., the effective viscosity model and thermal Reynolds equation model) being widely used in metal forming lubrication literature. It is found that neither of the two approximate models is more accurate than the other and that neither can deal with the effect of surface temperature difference of the roll and strip adequately.

Study of Friction in Cold Strip Rolling

1984 ◽  
Vol 106 (2) ◽  
pp. 139-146 ◽  
Author(s):  
Lim Lai-Seng ◽  
J. G. Lenard
Keyword(s):  
Aluminum Alloys ◽  
Coefficient Of Friction ◽  
Strip Rolling ◽  
Roll Pressure ◽  
Average Coefficient ◽  
The Coefficient Of Friction ◽  
Frictional Coefficients ◽  
Roll Gap ◽  
Cold Strip Rolling

Experiments were conducted to measure the effects of roll pressure and roll rpm on the magnitude and variation of the coefficient of friction in the roll gap in cold strip rolling. Two aluminum alloys (1100-T0 and 5052-H34) were used in the experiments. Roll pressures were found not to affect the frictional coefficients in a significant manner. Speed of rolling was identified as the most important parameter as far as the values of μ are concerned. Increased speeds appeared to lower the values of the average coefficient of friction.

A Study of Cold Strip Rolling

1979 ◽  
Vol 101 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Arvind Atreya ◽  
John G. Lenard
Keyword(s):  
Exact Solution ◽  
Two Dimensional ◽  
Strip Rolling ◽  
Roll Pressure ◽  
Present Technique ◽  
Dimensional Finite Element ◽  
Accurate Comparison ◽  
Roll Deformation ◽  
Cold Strip Rolling ◽  
Roll Shape

The effect of roll deformation on separating forces in cold strip rolling is studied. The deformed roll shape is determined by a two dimensional finite element routine. The results are then incorporated in an analysis of the mechanics of rolling. The technique consists of assembling individual slabs bounded by planes passing through nodal points on the arc of contact—for each of which an exact solution for the roll pressure is obtained. Comparison to the solution of Orowan’s equations shows that the present technique is reasonably accurate. Comparison to data from a preliminary set of experiments shows that the technique deserves further investigation.

Power Analysis of Cold Strip Rolling

1963 ◽  
Vol 85 (1) ◽  
pp. 77-88 ◽  
Author(s):  
B. Avitzur
Keyword(s):  
Coefficient Of Friction ◽  
Power Analysis ◽  
Simple Procedure ◽  
Simple Expression ◽  
Optimum Conditions ◽  
Strip Rolling ◽  
The Coefficient Of Friction ◽  
Separation Force ◽  
Cold Strip Rolling

In a previous paper criteria for maximum possible reduction were developed. A simple procedure for the experimental determination of the coefficient of friction was introduced. In this paper a solution for the efficiency is presented. A term called “Minimum Required Reduction,” which was briefly mentioned earlier [2], is discussed in detail. The results of experimental work for the determination of the coefficient of friction are described. A simple expression for the separation force is given. Finally, a procedure for optimum operation is suggested. The controllable variables are pointed out and the steps in the choice of the optimum conditions are described.

Effect of Liquid-Solid Lubricant on Mixed Lubrication in Line Contact

2011 ◽  
Vol 148-149 ◽  
pp. 778-784
Author(s):  
Rattapasakorn Sountaree ◽  
Panichakorn Jesda ◽  
Mongkolwongrojn Mongkol
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Solid Lubricant ◽  
Reynolds Equation ◽  
Contact Region ◽  
Mixed Lubrication ◽  
Line Contact ◽  
Load Carrying ◽  
Roughness Amplitude ◽  
Raphson Method

This paper presents the performance characteristics of two surfaces in line contact under isothermal mixed lubrication with non-Newtonian liquid–solid lubricant base on Power law viscosity model. The time dependent Reynolds equation, elastic equation and viscosity equation were formulated for compressible fluid. Newton-Raphson method and multigrid technique were implemented to obtain film thickness profiles, friction coefficient and load carrying in the contact region at various roughness amplitudes, applied loads, speeds and the concentration of solid lubricant. The simulation results showed that roughness amplitude has a significant effect on the film pressure, film thickness and surface contact pressure in the contact region. The film thickness decrease but friction coefficient and asperities load rapidly increases when surface roughness amplitude increases or surface speed decreases. When the concentration of solid lubricant increased, friction coefficient and asperities load decrease but traction and film thickness increase.

Influence of Laser Micro-Mesh Texturing on the Tribological Performance in an EHL Point Contact

2007 ◽  
Vol 353-358 ◽  
pp. 796-800
Author(s):  
Xiao Wang ◽  
Jian Li ◽  
Wei Chen ◽  
Lan Cai ◽  
Jian Ying Zhu
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Pressure Distribution ◽  
Reynolds Equation ◽  
Point Contact ◽  
Tribological Performance ◽  
Design And Optimization ◽  
Thickness Profile ◽  
Wide Range ◽  
Key Factor

Fabricating surfaces with controlled micro-geometry may be an effective approach to improved tribological performance. In this paper, the effect of laser surface micro-mesh texturing on the tribological performance is investigated theoretically with numerical solution of EHL point contact. In the theoretical model, the Reynolds equation is used as the governing equation. Well controlled micro-mesh texturing is described in film thickness equation. By Full Multi-Grid (FMG) method, the solutions of film thickness profile and pressure distribution map are present over a wide range of texturing parameters. The influence of width, depth and orientation of mesh texturing on the friction coefficient is analyzed. Result shows that, the film thickness profile and pressure distribution are sensitive to the parameters of micro-mesh texturing. The curve result of friction coefficient under two load conditions indicated that the parameters of mesh are key factor for texturing design. Solutions demonstrate the ability of numerical simulation on the design and optimization of surface mesh texturing.

scholarly journals Friction Characteristics of Liquid Lubricated MEMS with Deterministic Boundary Slippage

2014 ◽  
Vol 66 (3) ◽  
Author(s):  
Mohammad Tauviqirrahman ◽  
Muchammad Muchammad ◽  
Rifky Ismail ◽  
Jamari Jamari ◽  
Dik J. Schipper
Keyword(s):  
Film Thickness ◽  
Beneficial Effect ◽  
Friction Force ◽  
Coefficient Of Friction ◽  
Reynolds Equation ◽  
Friction Reduction ◽  
Hydrodynamic Performance ◽  
Friction Characteristics ◽  
Reduction Mechanisms ◽  
Boundary Slippage

It has been proven experimentally that boundary slippage represents a viable effect on the hydrodynamic performance of lubricated sliding contacts. Along with several friction reduction mechanisms that have been explored in the literature, the slippage parameters remain an important feature. With the main objective of evaluating the effects of the slippage, a modified Reynolds equation is employed. The result shows that deterministic boundary slippage of the lubricated-MEMS with uniform film thickness has a very beneficial effect on decreasing friction force as well as coefficient of friction.

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.

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