M390高碳马氏体不锈钢与304奥氏体不锈钢CMT对接焊连接机理  

CMT Butt Welding Mechanism of M390 Martensitic Stainless Steel and 304 Austenitic Stainless Steel

作　　者：乔丽学 曹睿[1] 车洪艳[2,3] 李晌 王铁军 董浩[2,3] 王彩芹 闫英杰[1] QIAO Lixue;CAO Rui;CHE Hongyan;LI Shang;WANG Tiejun;DONG Hao;WANG Caiqin;YAN Yingjie(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;Advanced Technology&Materials Co.,Ltd.,China Iron&Steel Research Institute Group,Beijing 100081,China;Engineering and Technology Research Center of Hot Isostatic Pressing,Zhuozhou 072750,Hebei,China;Bahuan Technology Group Co.,Ltd.,Taizhou 318054,Zhejiang,China)

机构地区：[1]兰州理工大学有色金属先进加工与再利用省部共建国家重点实验室,兰州730050 [2]中国钢研科技集团有限公司,安泰科技股份有限公司,北京100081 [3]河北省热等静压工程技术研究中心,河北涿州072750 [4]八环科技集团股份有限公司,浙江台州318054

出　　处：《材料导报》2023年第7期192-197,共6页Materials Reports

基　　金：国家自然科学基金(52175325,51961024,52071170)。

摘　　要：本工作以ERNi-1镍基焊丝为填充金属,通过冷金属过渡焊接技术(CMT)对粉末冶金制备的M390高碳马氏体不锈钢与304奥氏体不锈钢进行连接;采用拉伸实验、维氏显微硬度测试、SEM及EDS表征焊接接头力学性能及微观组织,统计焊缝及M390一侧不同区域的晶粒尺寸及碳化物分布情况,研究焊接接头的连接机理。研究结果表明:通过CMT对接焊成功实现M390高碳马氏体不锈钢与304奥氏体不锈钢的连接,得到无孔洞、无夹杂等缺陷的焊接接头。最佳焊接工艺参数为焊接速度4.5 mm/s、送丝速度9 m/min、焊接电流110 A、焊接电压18.1 V,对应焊接接头抗拉强度达到493 MPa、延伸率为21.8%,断裂于焊缝位置,且断裂类型为韧性断裂,其塑性远高于M390母材。焊缝组织由奥氏体组织及(Ti、Ni、Al)的碳化物组成。焊缝与M390实现良好的冶金结合,但在304熔合区有明显的熔合线。M390热影响区由于受热输入及焊接残余应力的影响,其基体中残留奥氏体被诱导发生马氏体相变,导致M390热影响区基体中碳元素过饱和,析出的碳元素不仅使得碳化物数量增加,而且促使碳化物类型由M_(23)C_(6)向M_(7)C_(3)发生转变。M390粗晶区碳化物尺寸最大,呈现出条形状形貌;M390细晶区碳化物尺寸介于M390母材与M390粗晶区之间,呈现出条形状和颗粒状两种形貌。M390高碳马氏体不锈钢一侧热影响区的晶粒尺寸明显小于采用传统熔化焊时马氏体钢热影响区的晶粒尺寸,充分体现CMT焊接对M390高碳马氏体不锈钢热影响区粗化问题的改善。M390 powder metallurgy high carbon martensitic stainless steel and 304 austenitic stainless steel are joined by cold metal transfer(CMT)butt welding experiments with ERNi-1 nickel-based metal as filler wire.The mechanical properties and microstructure of the welded joint were characterized by tensile experiment,vickers microhardness test,scanning electron microscope(SEM)and energy dispersive spectrometer(EDS).The grain size and carbide distribution in different areas on M390 side were measured to reveal the joining mechanism of the welded joint.The results show that:M390 high carbon martensitic stainless steel and 304 austenitic stainless steel CMT butt welding joints with no holes,no inclusions and other defects could be achieved.The best welding process parameters were welding speed of 4.5 mm/s,wire feeding speed of 9 m/min,welding current of 110 A,welding voltage of 18.1 V,the corresponding tensile strength and the elongation reached 493 MPa and 21.8%,respectively.Its plasticity was much higher than M390 base metal.The fracture location appeared at the weld metal position.Ductile fracture dominated the fracture surfaces.The weld metal is composed of austenite microstructure and(Ti,Ni,Al)carbides.Metallurgical bon-ding can be achieved between weld metal and M390.An obvious fusion line appears in 304 fusion zone.Because M390 heat-affected zone is affected by heat input and welding residual stress,the residual austenite in the matrix of M390 heat-affected zone is induced to undergo a martensitic transformation,which lead to the supersaturation of carbon in the matrix of M390 heat-affected zone.The precipitated carbon not only increases the number of carbides,but also promotes the type of carbides to change from M_(23)C_(6)to M_(7)C_(3).The size of carbide in M390 coarse-grained heat affected zone is the largest,showing a strip shaped morphology.The size of carbide in M390 fine-grained heat affected zone is located between M390 base metal and M390 coarse-grained heat affected zone,showing two morphology of strip s

关 键 词：M390高碳马氏体不锈钢 CMT 微观组织 力学性能 碳化物 

分 类 号：TG406[金属学及工艺—焊接]