Evaluation of Thermo-mechanical stress in work rolls of ring rolling mill under thermal and mechanical loading

The defect in work rolls directly influence the forming cost and the final shape of the product. The researchers tend to investigate the thermo-mechanical stress in work roll of rolling machines. These stresses may reduce the roll life. Since the investigation of the thermo-mechanical stress in work roll with real-conditions is complex, comprehensive studies by means of numerical methods are available in numerous literature. However, simulating the thermo-mechanical stress is time-consuming. So, most researchers desire to simplify the geometry and boundary conditions in order to reduce simulation cost. This paper proposes an integrated finite element model to study the thermo-mechanical behavior of work rolls during hot ring rolling process. Various methods were simulated and advantages and disadvantages of each method were discussed. Due to complexities of ring rolling process, the presented model was used in flat rolling in order to verify model integrity. After that work rolls of ring rolling mill subjected to partial boundary conditions are investigated. The results of thermal and thermo-mechanical simulations show stresses in the contact region of work rolls are rather different. However, they expressed the same results in other regions. Based on the obtained results, it is revealed that the effect of mechanical loads in the equivalent stresses should be considered and the location of equivalent maximum stress is below the surface.