关键词: 热疲劳失效, 瞬态温度场, 瞬态应力场, 有限元模拟, 中间罐罐盖

Abstract: Surface fracture at high temperature is a serious engineering problem is caused by thermal effect. Surface thermal cracking, surface layer peeling off and heat brittle fracture induced by thermal cycling are the primary failure forms of workpieces such as continuous casting tundish covers, hot rolls and die casting dies. Thermal fatigue cracking damage is mainly caused by the combined action of thermal stress and thermal impact stress. According to the basic theories of finite element method and heat transfer, transient temperature and stress fields of the continuous casting tundish cover are calculated by using the ANSYS finite element software based on the physical description of its failure under thermal fatigue condition. The relationship between the fatigue damage and stress field of the critical point is also analyzed. Besides, the temperature, stress, strain and failure process of the tundish cover are reproduced through ANSYS finite element simulation and practical fatigue failure analysis, the finite element model and the solving conditions are determined. Comparing the simulation results with the real situation, it is proved that the solving conditions for the finite element computation of the stress field are accurate and the finite element model is reasonable. Therefore, a finite element analysis method for the thermal fatigue failure of practical components is proposed. It is believed that the improvement of thermal fatigue resistance mainly depends on the structure and the materials of the tundish cover used. The further study of the problem will provide the theoretical basis for the subsequent material and structure optimization of the tundish cover. And it will have important reference value for the thermal fatigue damage problem, life prediction and control of working equipment under high temperature and thermal shock conditions.

Key words: Continuous casting tundish cover, Finite element simulation, Thermal fatigue failure, Transient stress field, Transient temperature field