晶粒尺度对镍基高温合金的高温失塑裂纹敏感性的影响  

Influence of grain size on susceptibility of ductility-dip crack on Ni-based high-temperature alloy

作　　者：陈静青[1,2] 陆皓[2] 陈辉[1] 苟国庆[1] 

机构地区：[1]西南交通大学材料科学与工程学院,四川成都610031 [2]上海交通大学材料科学与工程学院,上海200240

出　　处：《电焊机》2015年第6期21-25,共5页Electric Welding Machine

摘　　要：镍基高温合金FM-52M是被广泛应用于核电关键部件焊接结构的熔敷金属。但在厚壁管道焊接中,FM-52M的窄间隙填充焊缝具有明显的高温失塑裂纹(DDC)倾向。由于该类热裂纹缺陷的存在,将导致关键部件的焊接结构在核电严苛环境中服役时出现极大的安全隐患。目前在压力容器安全端等厚壁管道焊接制造中,仍无法完全避免该缺陷。针对该问题,提出了采用脉冲TIG焊细化FM-52M的焊缝微观结构改善材料的高温力学性能。通过基于Gleeble技术的单向拉伸试验(STF试验)对FM-52M填充焊缝的DDC裂纹敏感性进行评估,结果证实细化的微观组织提高了DDC裂纹的临界应变,增加了该熔敷金属的抗DDC性能。Ni-based high-temperature alloy FM-52M （a filler metal of Incone1690） is widely applied on welding structure of nuclear power key conlponeut.However, a solid-state intergranular crack, called ductility-dip crack （DDC） is found in nan＇ow gap filler weld of FM-52M during the welding process of thick-wall pipeline.As the key component serves in a severe condition of high pressure and temperature and corrosive atmosphere,the existence of DDC will greatly affect the safety and life expansion of nuclear power plant.Thus the impulse TIG welding is introduced in this work to resolve the DDC defect during thick-wall pipeline welding of safety ending.Besides,a strain-to-fracture （STF） test based on Gleeble-3500 thermo-mechanieal simulator is performed to evaluate the DDC susceptibility of FM-52M.The resuhs show that resistance of DDC of this deposited metal is improved by the refined microstrucre by impulse TIG wehting.

关 键 词：镍基高温合金 高温失塑裂纹 裂纹评估 

分 类 号：TG457.1[金属学及工艺—焊接]