Chapter 6 - An Examination of the Coefficient of Friction

Abstract

Product and process design needed for the development of draft schedules in the flat rolling industry, make use of off-line mathematical models of the process. These models vary broadly in their complexities and sophistication and they include simple and one-dimensional descriptions. Alternatively, they may be especially written, dedicated finite-element, or finite-difference descriptions of the process. All of them may be used to gain insight into the behavior of the three components of the metal rolling system—mill, the rolled metal, and their interface. When hot rolling is modeled, the resulting grain distribution, the retained strain, the amount of recrystallization, and precipitation may be calculated. The boundary conditions are often expressed in terms of the coefficient of friction and the coefficient of heat transfer. In the cold rolling process with adequate application of lubrication the coefficient of friction is the more important of the two, while in hot rolling both coefficients are of significant importance.