Prediction of work-rolls failure in hot ring rolling process

Abstract

The work-rolls of the hot ring rolling process are subjected to various damages due to the contact with hot metal. Thermo-mechanical fatigue is one of these damages. In order to predict failure due to the thermo-mechanical stress in the work-rolls, the developed code in ABAQUS has been used. The comparison between three- and two-dimensional models and, also, thermal and thermo-mechanical response of work-rolls with variable boundary conditions has been investigated. The results have shown that by applying mechanical and thermal loads separately or simultaneously, the response of work-rolls is completely different. In the mandrel, the location of the maximum equivalent stress is on the surface, while the location of equivalent maximum stress is in the subsurface of the main-roll. By making use of cumulative damage rules and the stress life method, the thermo-mechanical fatigue life was estimated. The cumulated damage in the mandrel’s surface was higher than subsurface regions. In contrast to the mandrel, the cumulated damage in the main-roll’s subsurface was higher than surface regions. In hot ring rolling machines, these locations are prone to crack initiation as a result of the thermo-mechanical fatigue in the work-rolls.