镍铝青铜-钢异质金属焊接接头组织与力学性能  

Microstructure and mechanical properties on dissimilar-welded joints of nickel-aluminum bronze and steel using TIG welding

作　　者：吴栋[1] 杨帆[1] 胡小强[1] 陆善平[1] WU Dong;YANG Fan;HU Xiaoqiang;LU Shanping(Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,Liaoning pro.,China)

机构地区：[1]中国科学院金属研究所沈阳材料科学国家研究中心,辽宁沈阳110016

出　　处：《焊接技术》2023年第6期16-20,I0005,共6页Welding Technology

基　　金：中国科学院战略性先导科技专项(XDC04030500/XDC04030504);国家重点研发计划资助项目(2018YFA0702902)。

摘　　要：采用手工钨极氩弧焊对镍铝青铜QAl10-5-5/低合金钢Q355进行了焊接试验,焊丝采用高Mn镍铝青铜SCu6338。对焊接接头的微观组织、拉伸、弯曲及冲击性能进行了考察与研究。结果表明,焊缝与两侧母材均达到冶金结合,焊缝由α-Cu相和富Fe组织(宏观泛铁带和富Fe枝晶)组成,富Fe组织周围存在少量微米级凝固微裂纹,凝固裂纹在被富Fe组织包围的残余铜相中形成,表明焊接时应控制钢的熔入量和富Fe组织分布均匀性。铜-钢异质界面无明显缺陷产生,形成了一层厚度约2μm的Fe-Al中间化合物层。焊接热循环作用下,镍铝青铜侧热影响区α相减少,主要为残余β相和α/κ共生相为主,其韧性较焊缝和钢侧热影响区的低。Q355侧热影响区为贝氏体组织。焊接接头弯曲测试后表面无宏观缺陷,接头拉伸均断在Q355母材,表明焊接接头力学性能良好。The welding tests of nickel-aluminum bronze QAl10-5-5/low alloy steel Q355 were carried out by manual tungsten argon arc welding,and the filler wire was a manganese-aluminum bronze SCu6338.The microstructure,tensile,bending and impact properties of the welded joints were investigated and analyzed.The results showed that a metallurgical bonding was achieved between the weld metal and the base metal,the weld was composed ofα-Cu phase and Fe-rich structure(macroscopic Fe belt and microscopic Fe-rich dendrites).A small number of solidification micro-cracks exist around the Fe-rich structure,which were formed in the residual copper phase surrounded by the iron-rich structure,indicating that the melting amount of the steel and the uniformity of iron-rich microstructure distribution during welding should be controlled.No obvious defect was observed at the QAl10-5-5/Q355 interface,where a Fe-Al intermediate compounds layer with a thickness of about 2μm was formed.The QAl10-5-5 HAZ mainly contained the residualβphase and theα/k symbiotic phase,since theαphase was reduced due to the welding thermal cycle,which deceased the QAl10-5-5 HAZ toughness.The Q355 HAZ was observed to be bainite.No macro-defect was observed on the surface of the welded joints after the bending test,and the tensile test showed that fracture occurred in the Q355 base metal.It indicated that the mechanical properties of the welded joints were good.

关 键 词：镍铝青铜 铜-钢异质焊接接头 微裂纹 力学性能 

分 类 号：TG442.3[金属学及工艺—焊接]