焊后热处理对高强钢S420ML焊接接头CTOD性能的影响  

Effect of Post-weld Heat Treatment on CTOD Properties of Welded Joint of S420ML High Strength Steel

作　　者：张欣耀[1,2] 刘勇 郑国华 张利娟[1] 赵阳[1] 查小琴[1,2] ZHANG Xinyao;LIU Yong;ZHENG Guohua;ZHANG Lijuan;ZHAO Yang;ZHA Xiaoqin(Luoyang Ship Material Research Institute,Luoyang 471023,China;Henan Key Laboratory of Technology and Application of Structural Materials for Ships and Marine Equipments,Luoyang 471023,China;Nanjing Iron&Steel Co.Ltd.,Nanjing 210035,China)

机构地区：[1]中国船舶重工集团公司第七二五研究所,河南洛阳471023 [2]河南省船舶及海工装备结构材料技术与应用重点实验室,河南洛阳471023 [3]南京钢铁股份有限公司,江苏南京210035

出　　处：《材料开发与应用》2020年第5期1-6,共6页Development and Application of Materials

基　　金：高速铁路装备材料生产应用示范平台(TC190H3ZV/2)。

摘　　要：采用断裂韧性测试和宏观断口分析等方法,研究了焊后热处理对高强钢S420ML焊接接头焊缝、粗晶区、回火区和部分相变区分界线的断裂韧性CTOD的影响。结果表明,80 mm厚S420ML焊接钢板,无论是否经过焊后热处理,其断裂韧性CTOD性能均能满足相关标准要求,同时580℃×4 h焊后热处理能够显著提升断裂韧性CTOD特征值;特征值为δm的试样,裂纹扩展面以纤维区为主,特征值为δu的试样,裂纹扩展面初始阶段包含部分脆断区,随后由于载荷释放,裂纹扩展停止,材料及时止裂。在后续加载时重新获得裂纹扩展抗力,断口的剩余部分仍呈现纤维断裂的特征。Fracture toughness test and scanning electron microscopy(SEM)were adopted to investigate the effects of post-weld heat treatment(PWHT)on the joint weld,coarsened grain zone,and CTOD properties of line between subcritical HAZ and intercritical HAZ of welded joint of S420ML high-strength steel for offshore engineering.Results showed that the CTOD properties of 80 mm thick S420ML welded steel plate could satisfy the requirements of relevant standards whether the plate went through post-weld heat treatment or not,and that the CTOD properties of welded plates were significa ntly improved after PWHT at 580℃ for 4 hours.The crack propagation surface of specimen with characteristic value of δm were mainly characterized by fiber zone,and for the specimen with characteristic value of δu,the initial stage of the crack propagation surface had some brittle fracture regions,then due to the release of load,the crack propagation stopped,and the cracking stopped in time.The crack propagation resistance was regained during subsequent loading,so that the remaining part of the fracture still presented the characteristic of fiber fracture.

关 键 词：高强钢 CTOD 焊后热处理 宏观断口分析 

分 类 号：TG142[一般工业技术—材料科学与工程]