金属热处理 ›› 2024, Vol. 49 ›› Issue (11): 178-184.DOI: 10.13251/j.issn.0254-6051.2024.11.027

• 工艺研究 • 上一篇    下一篇

焊后热处理对Sanicro25/G115异种钢接头组织及力学性能的影响

李林平1, 刘艳荣2, 杨茂鸿3, 杜晋峰1, 张峥4   

  1. 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
  • 收稿日期:2024-05-15 修回日期:2024-09-20 出版日期:2024-11-25 发布日期:2025-01-09
  • 作者简介:李林平(1986—),男,高级工程师,博士,主要研究方向为电站金属材料组织与性能,E-mail:lilimping@163.com

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

Li Linping1, Liu Yanrong2, Yang Maohong3, Du Jinfeng1, Zhang Zheng4   

  1. 1. CHN Energy New Energy Technology Research Institute Co., Ltd., Beijing 102209, China;
    2. China Academy of Aerospace Standardization and Product Assurance, Beijing 100071, China;
    3. China-Ukraine Institute of Welding Guangdong Academy of Sciences, Guangzhou Guangdong 510650, China;
    4. School of Materials Science and Engineering, Beihang University, Beijing 100191, China
  • Received:2024-05-15 Revised:2024-09-20 Online:2024-11-25 Published:2025-01-09

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M23C6、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 ℃。

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

Abstract: 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 M23C6 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 ℃.

Key words: Sanicro25 steel, G115 steel, hetero-steel welded joint, post-weld heat treatment (PWHT), microstructure, tensile properties

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