氩弧焊焊接18Ni马氏体时效钢(250)薄板焊接接头的组织和力学性能研究  

Study on the microstructure and mechanical properties of the welded joints of 18Ni maraging steel(250)sheets welded by argon arc welding

作　　者：陈元园 沈少波[1] 汪晨 李嘉庆 CHEN Yuanyuan;SHEN Shaobo;WANG Chen;LI Jiaqing(School of Metallurgy and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083

出　　处：《四川冶金》2022年第1期44-49,61,共7页Sichuan Metallurgy

摘　　要：采用氩弧焊对3 mm厚的18Ni马氏体不锈钢(250)薄板实施焊接,并针对获得的焊接接头的表观质量、显微组织和力学性能进行了分析研究。结果表明,焊接试样的焊缝宽度约6mm,焊缝组织由等轴晶、柱状晶、树枝晶和逆转变奥氏体构成;熔合区是焊缝区与热影响区的过渡区域,宽度很窄;热影响区主要分为HAZ1(黑色区域Ⅰ)、HAZ2(白色区域)与HAZ3(黑色区域Ⅱ),HAZ1(黑色区域Ⅰ)的组织主要由颗粒粗大的条状马氏体构成,HAZ2(白色区域)的组织由条状马氏体、残余奥氏体和金属强化物构成,HAZ3(黑色区域Ⅱ)的组织形貌与母材组织相似,均由条状马氏体构成;显微硬度测试表明焊接接头的硬度分布曲线呈马鞍形,其中焊缝区域的平均硬度最低是318.1 HV,HAZ1(黑色区域Ⅰ)的平均硬度是353.5 HV,HAZ2(白色区域)的平均硬度最高为406.5 HV,HAZ3(黑色区域Ⅱ)的平均硬度是387.2 HV;电镜结果证明焊缝区域存在元素偏析;室温拉伸性能结果表明,断裂是从HAZ1(黑色区域Ⅰ)产生。Argon arc welding was used to weld a 3 mm thick 18Ni martensitic stainless steel sheet(250), and the apparent quality, microstructure and mechanical properties of the obtained welded joint were analyzed and studied. The results show that the weld width of the welded sample is about 6 mm, and the weld structure is composed of equiaxed crystals, columnar, crystal dendrites and reverse transformed austenite;the fusion zone is very narrow and is that the transition zone between the weld zone and the heat-affected zone;The affected zone is mainly divided into HAZ1(black area Ⅰ), HAZ2(white area) and HAZ3(black area Ⅱ). The structure of HAZ1(black area Ⅰ) is mainly composed of coarse-grained strip martensite, the structure of HAZ2(white area) is composed of strip martensite, retained austenite and metal reinforcement, the structure of HAZ3(black area Ⅱ) is similar to the structure of the base material and it is composed of strip martensite;the microhardness test shows that the hardness distribution curve of the weld joint is saddle-shaped, in which the average hardness of the weld area is the lowest and is 318.1 HV, the average hardness of HAZ1(black area Ⅰ) is 353.5 HV, the average hardness of HAZ2(white area) is the highest and is 406.5 HV, and the average hardness of HAZ3(black area Ⅱ)is 387.2 HV;electron microscopy results prove that there is element segregation in the weld zone;the tensile properties at room temperature show that the fracture is generated from HAZ1(black zone Ⅰ).

关 键 词：马氏体不锈钢 氩弧焊焊接 力学性能 显微组织 

分 类 号：TG113.25[金属学及工艺—物理冶金]