T91/HR3C异种耐热钢焊接接头蠕变失效有限元模拟  

Numerical simulation on creep failure of T91/HR3C heat-resistant steels welded joint

作　　者：张建强[1] 张国栋[1] 姚兵印[2] 李太江[2] 刘福广[2] 

机构地区：[1]武汉大学动力与机械学院,武汉430072 [2]西安热工研究院有限公司,西安710032

出　　处：《焊接学报》2013年第7期68-72,116,共5页Transactions of The China Welding Institution

基　　金：湖北省自然科学基金资助项目(2007ABA040);先进焊接与连接国家重点实验室开放课题

摘　　要：采用有限元方法建立马氏体T91/新型奥氏体HR3C异种耐热钢焊接接头蠕变数值模型,模拟600℃/42.26 MPa内压作用下的蠕变最大主应力、von Mises等效应力和应力三轴度分布.结果表明,最大主应力峰值位于接头内表面的焊缝/T91和HR3C/焊缝界面以及距外表面2.96 mm处的焊缝/T91界面附近区域.内表面焊缝/T91界面区域von Mises等效应力数值最大,依次为距内表面1.29 mm处焊缝/T91界面区域、外表面和距外表面2.96 mm处焊缝/T91界面区域.内表面焊缝/T91界面处的应力三轴度数值较高,孔洞易于扩张、形成界面蠕变裂纹.而距内表面1.29 mm处和距外表面2.96 mm处的细晶HAZ内应力三轴度数值较高,两部位的孔洞容易连接形成IV型蠕变裂纹.采用应力三轴度分析T91/HR3C钢接头焊缝/T91界面失效和T91细晶HAZ蠕变孔洞扩张及裂纹扩展特性更为准确,与加速试验结果比较一致.The FEM model of dissimilar welded joints between martensitic heat-resistant steel(T91) and austenitic(HR3C) was established to study the creep failure.The maximum principal stress,von Mises equivalent stress,stress triaxiality were simulated at 600 ℃ and under the inner pressure of 42.26 MPa.The results show that the peaks of the maximum principal stresses are in the interface of weld/T91 and HR3C/weld on inner surface,and in the vicinity of weld/T91 interface in the distance of 2.96 mm from outer surface.The highest von Mises equivalent stress is in the weld/T91 interface of inner surface,successively,in the weld/T91 interface of 1.29 mm from inner surface,outer surface and 2.96 mm from outer surface.The stress triaxiality in the weld/T91 interface of inner surface is quite high,creep cavities are easily to link interfacial creep cracks.And that,the stress triaxiality in the fine grain HAZ of 1.29 mm from inner surface and 2.96 mm from outer surface are also quite high,accordingly,creep cavities are easily to form type IV creep cracks.Therefore,using stress triaxiality to describe creep cavity expansion and crack development of weld/T91 interface and fine grain HAZ is more reasonable for the dissimilar welded joint of T91/HR3C,and the numerical simulating results are good in agreement with those experiments.

关 键 词：马氏体耐热钢 奥氏体耐热钢 最大主应力 等效应力 应力三轴度 

分 类 号：TG407[金属学及工艺—焊接]