FEM simulation of thermo-mechanical stress and thermal fatigue life assessment of high-speed steel work rolls during hot strip rolling process

Abstract

Work rolls used for hot strip rolling undergo the cyclic sequence of heating-cooling over the roll surface due to contact with the hot strip and the following cooling systems during every rolling revolution. Severe temperature gradient and thermal stress caused by cyclic heating-cooling loading are dominant factors for thermal fatigue failure of work rolls. Therefore, investigations on temperature and thermal stress-strain are essential for understanding the thermal fatigue of work roll. In this study, a thermo-mechanical analysis with elastic-plastic material parameters via a simplified finite element model is carried out to compute the stress-strain range experienced by the work roll during rolling and idling. Then, a model with the initial crack in the roll surface considering different depths and a model with the hot strip is conducted to better understand the thermal behaviors of the work roll during hot rolling respectively. Furthermore, the thermal fatigue life of work roll is assessed based on the modified Coffin-Manson relation, considering the effect of multi-axial stress state and temperature-dependent material properties caused by temperature fluctuations in work roll during hot rolling.

Keywords:

• FEM
• hot rolling
• thermal fatigue
• thermo-mechanical stress
• work roll

Acknowledgments

The authors would also like to acknowledge Nao-aki Noda and Yoshikazu Sano from Kyushu Institute of Technology for their kind supports and valuable suggestion in this study.

Disclosure statement

The authors declare that they have no competing interests.

Additional information

Funding

The authors would like to express their thanks for the support by the Natural Science Foundation of Jiangsu Province (No. BK20181039), Natural Science Foundation of Jiangsu Province (No. BK20181044), and National Natural Science Foundation of China (No. 51801083).