Sanicro25/G115异种钢焊接接头的微观组织及力学性能  

Microstructure and mechanical properties of Sanicro25/G115 dissimilar welded joint

作　　者：李林平 杨茂鸿 杜晋峰 张峥[3] LI Lin-ping;YANG Mao-hong;DU Jin-feng;ZHANG Zheng(CHN ENERGY New Energy Technology Research Insititute Co Ltd,Beijing 102209,China;Centre of Excellence for Advanced Materials,Dongguan 523808,China;School of Materials Science and Engineering,Beihang University,Beijing 100191,China)

机构地区：[1]国家能源集团新能源技术研究院有限公司,北京102209 [2]东莞材料基因高等理工研究院,广东东莞523808 [3]北京航空航天大学材料科学与工程学院,北京100191

出　　处：《材料热处理学报》2023年第11期200-208,共9页Transactions of Materials and Heat Treatment

摘　　要：选用ERNiCrCoMo-1为焊丝,利用钨极氩弧焊(GTAW)对Sanicro25/G115异种钢进行焊接。采用光学显微镜、扫描电镜、透射电镜和拉伸试验等研究了焊接接头的微观组织及力学性能。结果表明:焊缝、Sanicro25钢及其热影响区的微观组织均为奥氏体+析出相;G115钢及其热影响区组织为回火马氏体,G115钢母材仍保持规则的马氏体板条形态,板条平均宽度约为466 nm;G115钢侧细晶热影响区(FGHAZ)马氏体板条特征消失,形成位错密度较低的亚晶,M_(23)C_(6)相、MX相分别沿亚晶界、晶内分布;G115钢侧焊缝及熔合线附近未形成δ-铁素体。焊缝显微硬度为246 HV0.1,紧邻焊缝G115钢侧粗晶热影响区(CGHAZ)的硬度最高,FGHAZ的硬度最低;母材经历焊接热循环及焊后热处理,Sanicro25钢的硬度由230 HV0.1增至246 HV0.1,G115钢由263 HV0.1降至250 HV0.1。接头呈韧性断裂,室温强度、650℃高温屈服强度均高于母材标准下限值,断裂位置位于G115钢侧细晶热影响区。Select ERNiCrCoMo-1 as the welding wire and use tungsten argon arc welding(GTAW)to weld Sanicro25/G115 dissimilar steel.Microstructure and mechanical properties of the welded joint were studied by means of optical microscope,scanning electron microscopy,transmission electron microscopy and tensile testing.The results show that the microstructure of the weld,Sanicro25 steel and its heat affected zone(HAZ)is austenite+precipitated phase.The microstructure of the G115 steel and its heat affected zone is tempered martensite,and the base metal of the G115 steel still maintains regular martensitic lath with width of about 466 nm.The martensitic lath characteristics in fine grained heat affected zone(FGHAZ)of the G115 steel side disappear,forming subgrains with lower dislocation density,and M_(23)C_(6)and MX phases are distributed along subgrain boundaries and within grains respectively.There is noδ-ferrite observed near the weld and fusion line of the G115 steel side.The microhardness of the weld is 246 HV0.1,and the hardness of the coarse grain heat affected zone(CGHAZ)adjacent to the G115 steel side of the weld is the highest,while the hardness of FGHAZ is the lowest.The hardness of the Sanicro25 steel increases from 230 HV0.1 to 246 HV0.1,while the hardness of the G115 steel decreases from 263 HV0.1 to 250 HV0.1 after welding thermal cycle and post-weld heat treatment.The welded joint exhibits ductile fracture,and the strength at room temperature and yield strength at 650℃are higher than the standard lower limit of the base metal.The fracture location is located at the FGHAZ of the G115 steel side.

关 键 词：Sanicro25钢 G115钢 异种钢焊接接头 微观组织 力学性能 

分 类 号：TG407[金属学及工艺—焊接]