Strain ageing embrittlement behaviour of X80 self-shielded flux-cored girth weld metal

作者：Lei Guo, Xin Su, Lianshuang Dai, Leilei Wang, Qiaofei Sun, Chaohai Fan, Yalei Wang, Xueda Li · 发表于：Materials Technology · 年份：2023 · DOI：10.1080/10667857.2023.2164978 · 被引用次数：29 · 研究领域：Microstructure and Mechanical Properties of Steels、Hydrogen embrittlement and corrosion behaviors in metals、Welding Techniques and Residual Stresses

Strain ageing embrittlement behaviour of X80 self-shielded flux-cored arc welding (FCAW) girth weld metal at different strain ageing conditions (1% prestrain, and aged at 150°C/100°C for 1 –6 h, and 80°C for 1–30 days) was studied. Microstructure of FCAW girth weld generally consisted of coarse granular bainite and lath bainite. After strain ageing, toughness notably decreased, and higher ageing temperature or longer ageing induced lower toughness, until ageing is fully yielded. At initial stage of strain ageing, more dimples were found accompanying with cleavage facet. With the progress of strain ageing, the embrittlement was more obvious, while larger cleavage facet and less dimples were found. Meanwhile, the critical size for cleavage fracture initiation site became smaller. Martensite–austenite constituent (1–2 μm) was found to initiate cleavage fracture when partially strain aged, while submicron inclusions could initiate cleavage facet when fully strain aged.