Influence of thermal stresses on the phenomenon of thermal fatigue of rolling cylinders

Abstract

Hot rolling cylinders are the most important machine parts in plastic deformation equipment. They are taken out of operation due to breakage caused by the predominant action of thermal stresses which cause accidental breakdowns of rolling mills. In view of these aspects, the question arose is to knowing the nature of these stresses, as well as their evaluation. This paper will experimentally determine the mechanical and thermal stresses that arise in the process of plastic deformation of hot rolling cylinders. The purpose of this paper is to evaluate the thermal stresses and compare them with the mechanical ones, as well as to highlight their influence on the thermal fatigue phenomenon. The study shows that the stresses in rolling cylinders are cyclical and occur at each rotation of the cylinders. The thermal stresses are mainly the result of the action of symmetric and asymmetric temperature fields. The overall action of thermal stresses presents an aspect of destruction of the surface layer that characterizes the effect of thermal fatigue phenomenon. The separation of the temperature fields that produce thermal stresses in symmetric and asymmetric and their experimental confirmation represents the originality of the research presented in this paper.