热处理状态下X80钢焊缝的低温脆化
Low Temperature Embrittlement of X80 Steel Weld After Heat Treatment
牛 靖1,2, 刘迎来1, 冯耀荣1, 张建勋2
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作者单位:1.中国石油天然气集团公司 西安管材研究所,陕西 西安 710065;2.西安交通大学 材料科学与工程学院,陕西 西安 710049
中文关键字:X80钢; 焊后热处理; 粒状贝氏体; 热处理; 脆化
英文关键字:X80 steel; post-weld heat treatment; granular bainite; heat treatment; embrittlement
中文摘要: 利用组织分析、冲击试验、断口分析等手段,对厚板X80钢埋弧焊缝的热处理组织和低温韧性进行了研究。结果表明,经过焊后热处理后焊缝出现严重的低温脆化,其冲击试样的断口为解理状形貌;淬火温度越高,焊缝脆化越严重;以针状铁素体为主的焊态焊缝,经过焊后热处理后形成的粗大粒状贝氏体是焊缝脆化的直接原因。冲击试样取样位置对焊缝冲击性能有明显的影响,板厚1/2位置的低温冲击功均低于1/4位置。
英文摘要:The heat treatment microstructure and low temperature toughness of X80 steel were investigated by microstructure analysis, impact test and fracture analysis. The results show that after post-weld heat treatment(PWHT), the welds of X80 steel seriously embrittle, and the fracture morphology of impact specimens is cleavage. The embrittlement of the welds increases with the increase of quenching temperature of PWHT. Coarsened granular bainite(GB)forms in the welds after PWHT, which directly results in the embrittlement of the welds. The effects of sampling position on low temperature impact property of the welds are obvious, and the impact energy of 1/2 plate thickness is lower than that of 1/4 plate.