焊后热处理对Sanicro25/G115异种钢接头组织及力学性能的影响  

Effect of PWHT on microstructure and mechanical properties of Sanicro25/G115 hetero-steel welded joint

作　　者：李林平 刘艳荣 杨茂鸿 杜晋峰 张峥[4] Li Linping;Liu Yanrong;Yang Maohong;Du Jinfeng;Zhang Zheng(CHN Energy New Energy Technology Research Institute Co.,Ltd.,Beijing 102209,China;China Academy of Aerospace Standardization and Product Assurance,Beijing 100071,China;China-Ukraine Institute of Welding Guangdong Academy of Sciences,Guangzhou Guangdong 510650,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]中国航天标准化与产品保证研究院,北京100071 [3]广东省科学院中乌焊接研究所,广东广州510650 [4]北京航空航天大学材料科学与工程学院,北京100191

出　　处：《金属热处理》2024年第11期178-184,共7页Heat Treatment of Metals

摘　　要：利用钨极氩弧焊(GTAW)制备Sanicro25/G115异种钢焊接接头,采用金相显微镜、扫描电镜、拉伸试验机对焊后态、760℃回火态、780℃回火态焊接接头的显微组织及力学性能进行研究。结果表明,焊接接头Sanicro25钢侧母材、热影响区组织为奥氏体+析出相;焊缝组织呈胞状树枝晶形态;G115钢侧热影响区、母材为回火马氏体组织。经焊后热处理后,G115钢侧CGHAZ、FGHAZ及母材区析出相数量增多,原奥氏体晶界、马氏体板条界分布有M_(23)C_(6)、MX析出相。室温拉伸下焊后态呈准解理脆性断裂,760℃回火态、780℃回火态呈韧性断裂,断裂位置由焊缝转移至G115钢侧FGHAZ;高温(650℃)拉伸下三者均呈韧性断裂,断裂位置由G115钢侧母材转移至G115钢侧FGHAZ。推荐焊后热处理温度为780℃。Sanicro25/G115 hetero-steel welded joint was prepared by using gas tungsten arc welding(GTAW),then the microstructure and mechanical properties of the joints as-welded,tempered at 760℃and tempered at 780℃were investigated,respectively,by means of optical microscope,scanning electron microscope and tensile testing machine.The results show that the microstructure of base metal and heat-affected zone(HAZ)at the Sanicro25 steel side is austenite with precipitated phase.The welding seam has a cellular dendritic morphology,and the HAZ and base metal at the G115 steel side are tempered martensite.After post-weld heat treatment(PWHT),the number of precipitated phases in CGHAZ,FGHAZ and base metal of the G115 steel side increases,and M_(23)C_(6) and MX precipitated phases are distributed in the prior austenite grain boundary and martensitic lath boundary.Under tensile test at room temperature,quasi-cleavage brittle fracture occurs in the joint as-welded,and ductile fracture occurs in the joints tempered at 760℃and 780℃.The rupture position is transferred from the welding seam to the FGHAZ at the G115 steel side.Under 650℃tensile test,the joints under different states all show ductile fracture,and the rupture position is transferred from G115 steel side base metal to G115 steel side FGHAZ.It is recommended that the PWHT temperature should be controlled at 780℃.

关 键 词：Sanicro25钢 G115钢 异种钢焊接接头 焊后热处理 显微组织 拉伸性能 

分 类 号：TG441.8[金属学及工艺—焊接] TG407