Understanding and Predicting Microevents Related to Scale Behavior and Formation of Subsurface Layers

Abstract

Research the behavior of oxide scale on a metal surface during different kinds of deformation at elevated temperatures has mostly been motivated by a desire to better understand the microscopic events at the tool/workpiece interface that could infl uence heat transfer, friction, descalability, and surface fi nish during hot rolling operations. Direct observations of oxide scale behavior under industrial hot working conditions is very diffi cult, while it is not much easier in the laboratory. Any single experiment is not capable of representing the full range of phenomena taking place during this high -temperature processing. Hence, a range of techniques have been developed, each providing a partial insight. The experimental results have been interpreted numerically; then a physically based numerical model of the rolling operation has been developed and used to simulate the process. Detailed fi nite element analysis allowed for the consideration of scale evolution and also for detailed understanding of the microevents both during testing and technological operations. Some results obtained by this complex investigation are presented in this chapter. After relevant adjustment of the mathematical model, it gives a basis for better prediction of the technological operation providing corresponding design criteria. 8.