Investigation on LCF Behavior of Welded Joint at Different Temperatures for Bainite Steel

Chinese Journal of Mechanical Engineering

Xiongfei Wang¹  Haichao Cui¹  Ke Xu¹  Fenggui Lu¹ 

[1]Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University

关键词: Low cycle fatigue;    Welded joint;    Different temperatures;    Failure mechanism;   

DOI  :  10.1186/s10033-019-0346-6

来源: DOAJ

【 摘 要 】

Abstract The current research of low cycle fatigue (LCF) is mainly focused on the components with uniform microstructure. Compared with these typical components, LCF behavior of welded components are more complex due to their great gradient microstructure, especially for different temperature. In this paper, LCF properties were conducted on the welded joint at different temperatures for bainite steel, and the failure mechanism was systematically discussed. Fatigue parameters derived from fitting curves indicated that welded joint had worse plastic deformation resistance and experienced more significantly strain hardening effect at 300 °C. The joint failed in the weld metal at room temperature, which attributed to the softening in weld metal combined with cyclic strain hardening effect in heat-affected zone, which meant the joint was more sensitive with the hardness at this condition. When it came to 300 °C, more cracks appeared near to HAZ and the heterogeneous distributed surface inclusion was responsible for the fracture transition to HAZ adjacent to bainite steel rather than the softest zone in HAZ, reflecting the joint was more sensitive with the surface inclusion at 300 °C. This research could support the design on loading of welded component at different temperature, and further ensure the safe operation.

【 授权许可】

Unknown