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.

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.

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.

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.

The Calculation of Roll Pressure in Hot and Cold Flat Rolling

1943 ◽  
Vol 150 (1) ◽  
pp. 140-167 ◽  
Author(s):  
E. Orowan
Keyword(s):  
Pressure Distribution ◽  
Yield Stress ◽  
Coefficient Of Friction ◽  
Static Friction ◽  
Rolled Stock ◽  
Theoretical Treatment ◽  
Frictional Drag ◽  
Roll Pressure ◽  
Plate Rolling ◽  
The Coefficient Of Friction

A numerical or graphical method is given for computing, in strip or plate rolling, the distribution of roll pressure over the arc of contact and the quantities derived from this (e.g. the vertical roll force, the torque, and the power consumption). The method avoids all mathematical approximations previously used in the theoretical treatment of rolling, and permits any given variation of the yield stress and of the coefficient of friction along the arc of contact to be taken into account. It can be used, therefore, in both hot and cold rolling, provided that the basic physical quantities (yield stress and coefficient of friction) are known. The usual assumption that the deformation could be regarded as a locally homogeneous compression has not been made, and the inhomogeneity of stress distribution has been taken into account approximately by using results derived by Prandtl and Nádai from the Hencky treatment of two-dimensional plastic deformation. It is found that the discrepancy between the roll pressure distribution curves calculated from the Kármán theory and those measured by Siebel and Lueg is due to the assumption in the theory that the frictional drag between the rolls and the rolled stock is equal to the product of the roll pressure and the coefficient of friction. If frictional effects are dominant, as in hot rolling, this product may easily exceed the yield stress in shear which is the natural upper limit to the frictional drag, and then static friction, instead of slipping, occurs. This has been taken into account in the present method, and the calculated curves of roll pressure distribution show good agreement with the curves measured by Siebel and Lueg.

Influence of the second-generation adaptive friction clutch configuration method (basic version) for its maximum load

2020 ◽  
pp. 552-557
Author(s):  
M.P. Shishkarev
Keyword(s):  
Safety Factor ◽  
Coefficient Of Friction ◽  
Second Generation ◽  
Maximum Load ◽  
Maximum Torque ◽  
Minimum Value ◽  
Average Coefficient ◽  
Friction Clutch ◽  
The Coefficient Of Friction ◽  
Basic Version

It is shown that the maximum torque of adaptive friction clutches of the second generation (baseline) when it is configured with the minimum coefficient of friction less than the setting based on an average coefficient of friction, if a ratio of the coefficient of friction to its minimum value more than the value of the safety factor.

A Finite Element Study of Flat Rolling

1988 ◽  
Vol 110 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Yhu-Jen Hwu ◽  
J. G. Lenard
Keyword(s):  
Finite Element ◽  
Coefficient Of Friction ◽  
Model Comparison ◽  
Element Solution ◽  
Eulerian Formulation ◽  
The Coefficient Of Friction ◽  
Flat Rolling ◽  
Roll Deformation ◽  
Roll Gap ◽  
Element Study

Using an Eulerian formulation, a finite element solution for the flat rolling problem is presented. Calculations are performed to establish the effects of roll deformation and of the variation of the coefficient of friction in the roll gap on the predictive capabilities of the model. Comparison to the data of Al-Salehi et al. (1973) and Shida and Awazuhara (1973) indicates that the differences between measurements and calculations decrease when the above-mentioned effects are accounted for.

Friction Effects on Through-Thickness Texture Evolution during Rolling

2005 ◽  
Vol 495-497 ◽  
pp. 567-572 ◽  
Author(s):  
J. Sarkar ◽  
S. Cao ◽  
Shigeo Saimoto
Keyword(s):  
Aluminum Alloys ◽  
Coefficient Of Friction ◽  
Texture Evolution ◽  
Mechanical Parameters ◽  
The Matrix ◽  
Roll Gap

Using AA5182 and 5754 aluminum alloys, the role of friction in through-thickness evolution was demonstrated. Aside from the mechanical parameters such as roll gap geometry and coefficient of friction, the significance of the role of Fe solute in the matrix was revealed.

Plowing Friction Under Harmonic Normal Loads

1999 ◽  
Vol 121 (2) ◽  
pp. 282-285 ◽  
Author(s):  
D. P. Hess
Keyword(s):  
Shear Strength ◽  
Coefficient Of Friction ◽  
Metal Surfaces ◽  
Sliding Friction ◽  
Normal Load ◽  
Hard Materials ◽  
Lubricated Contacts ◽  
Highly Nonlinear ◽  
Average Coefficient ◽  
The Coefficient Of Friction

The influence of harmonic normal loads on sliding friction is investigated through analysis of contacts consisting of conical and spherical sliders of hard materials on softer metal surfaces. Friction for such contacts is assumed to result from a plowing component and a shearing component. Calculations and experiments show that the coefficient of friction is essentially independent of normal load for contacts with conical sliders. However, for spherical sliders the relation between the coefficient of friction and normal load is highly nonlinear. In the presence of harmonic variations in normal load, this non-linearity causes a shift in the average coefficient of friction. For ideal lubricated contacts, the shearing component of friction is very small and for this case, it is shown that the maximum average reduction in the coefficient of friction is ten percent. When the shearing component is more significant, as with dry contacts, the shift is less. For example, when the shear strength is one-sixth the hardness of the softer material, the maximum average reduction in the coefficient of friction is five percent.

scholarly journals APPLICATION OF ANTIFRICTION COATINGS TO REDUCE CONTACT FRICTION IN STRETCH-FORMING PROCESS OF DOUBLE CURVATURE SHELLS ON A DIES MADE OF ALUMINUM ALLOYS

2021 ◽  
Vol 23 (1) ◽  
pp. 41-47
Author(s):  
G.L. Rivin ◽  
◽  
E.G. Karpukhin ◽  
A.O. Koshkina ◽  
◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Coefficient Of Friction ◽  
Contact Friction ◽  
Technological Properties ◽  
Stretch Forming ◽  
Forming Process ◽  
Properties Of Coatings ◽  
Double Curvature ◽  
Antifriction Coatings ◽  
The Coefficient Of Friction

The article presents the results of research on antifriction coatings for use on die made of aluminum alloys. The expediency of using antifriction coatings to reduce friction when stretch-forming of double curvature shells is justified. To substantiate this, we performed numerical modeling of the skin-tight forming process in the «LS-dyna» CAE system. According to the results of modeling, the following relationship is observed: the lower the coefficient of friction, the more evenly distributed the thinning deformations over the thickness of the blank in stretch-forming. Test modes for determining the coefficient of friction on the MTU-01 friction machine and methods for obtaining other basic functional and technological properties of antifriction coatings are described. The antifriction and technological properties of coatings, such as the coefficient of friction, adhesion, wear resistance, conditional hardness, the time and temperature of polymerization of the coating are determined.

Sign in / Sign up

Export Citation Format

Share Document