9Cr-1.5W-0.15Ta耐热钢搅拌摩擦焊焊缝组织和冲击性能分析  

Microstructure and impact properties for friction stir welds of 9Cr-1.5W-0.15Ta heat resistant steel

作　　者：张超 周猛兵 崔雷[2] 陶欣 王军[1] 王伟[1] 刘永长[3] ZHANG Chao;ZHOU Mengbing;CUI Lei;TAO Xin;WANG Jun;WANG Wei;LIU Yongchang(Fourth Institute of Nuclear Power Institute of China,Chengdu,610213,China;Tianjin Key Laboratory of Advanced Joining Technology,Tianjin University,Tianjin,300354,China;State Key Lab of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin,300354,China)

机构地区：[1]中国核动力研究设计院第四研究所,成都610213 [2]天津大学,天津市现代连接技术重点实验室,天津300354 [3]天津大学,水利安全与仿真国家重点实验室,天津300354

出　　处：《焊接学报》2024年第4期36-42,I0005,共8页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(52034004);中核集团专项(QBH201).

摘　　要：对9Cr-1.5W-0.15Ta耐热钢搅拌摩擦焊焊缝的微观组织演变和冲击性能进行了分析.结果表明,由于搅拌针剧烈的机械搅拌和焊接热循环的双重作用,搅拌摩擦焊缝区域内发生晶粒破碎、完全奥氏体化动态再结晶、晶界处M23C6相溶解和晶内M3C相析出,焊后较大的冷却速率抑制晶粒长大,促进了马氏体转变.在−100~20℃温度内进行了冲击试验,随着冲击试验温度的增加,母材和FSW焊缝的冲击吸收能量均表现为单调增大的特征,同时冲击断裂模式由脆性断裂逐渐转变为延性断裂.由于FSW焊缝中板条马氏体的形成、“针状”M3C碳化物的析出,FSW焊缝的硬度显著增大,并且在相同温度下FSW焊缝的冲击韧性发生降低,韧—脆转变温度由母材的−50℃升高至−40.2℃.In this paper,the microstructure evolution and impact properties of friction stir welds of 9Cr-1.5W-0.15Ta heat resistant steel were studied.The results showed that due to the double effects of the mechanical stirring of the stir tool and the welding thermal cycle,grain breaking,fully austenitized dynamic recrystallization,dissolution of M23C6 phase at the grain boundaries and formation of M3C are materialized in the welds.Higher cooling rate after welding restrains the growth of grains,and promotes martensite transformation.The impact test was conducted in the temperature range of−100~20℃.With the increase of impact test temperature,the impact absorbing energy of base metal and FSW weld metal is monotonously increased,and the impact fracture mode changes from brittle fracture to ductile fracture.Due to the formation of lath martensite and the precipitation of"acicular"M3C carbide in FSW weld,the hardness of FSW weld increases significantly.At the same temperature,the impact toughness of FSW weld decreases.And,the ductile-brittle transition temperature of FSW weld increases from−50℃of the base metal to−40.2℃.

关 键 词：9Cr-1.5W-0.15Ta耐热钢 搅拌摩擦焊 微观组织 冲击韧性 韧—脆转变温度 

分 类 号：TG456.9[金属学及工艺—焊接]