摘要
对SMA490BW耐候钢接头不同深度的缺陷进行了焊修,分析了补焊接头的组织、残余应力及力学性能。结果表明,2~6 mm深度缺陷的补焊不会对焊缝组织产生影响,焊缝组织主要为先共析铁素体、针状铁素体及粒状贝氏体。补焊对原焊缝产生热影响,形成正火细晶组织。补焊接头焊缝区的硬度低于初焊接头,补焊对接头的拉伸性能影响不大,但补焊接头的冲击性能优于初焊接头。随着缺陷深度的增加,补焊道次增加,致使接头及母材经历多次热循环,影响了接头残余应力分布。当补焊深度为6 mm时,焊缝附近纵向残余应力超过母材本身的屈服强度,而实际焊修后不再进行热处理,因此不建议对6 mm及以上深度的缺陷进行焊修。
Repair welding tests of SMA490BW welded joint with different depth defects were carried out.The microstructure,residual stress and mechanical properties of the repaired joints were studied.The results show that the repair welding for defects with the depth of 2-6 mm could not affect the weld structure,which is composed of proeutectoid ferrite,acicular ferrite and granular bainite.Repair welding has a thermal effect on the original weld and normalized fine grain structure is formed.The hardness of the weld zone of the repair welded joint is lower than that of the initial welded joint,and the repair welding has little effect on the tensile properties of the joints,but the impact properties of the repair welded joints are better than that of the initial joint.With the increase of defect depth,the number of repair welding passes increases,which makes the joint and the base metal suffer from multiple thermal cycles and affects the residual stress distribution of the joint.When the repair welding depth is 6 mm,the longitudinal residual stress near the weld exceeds the yield strength of the base metal itself,and the heat treatment is no longer carried out after the actual welding repair,therefore,it is not recommended to repair the defects with the depth more than 6 mm.
作者
邱培现
段卫军
李亚南
马征征
孙中文
余敏
QIU Peixian;DUAN Weijun;LI Yanan;MA Zhengzheng;SUN Zhongwen;YU Min(CRRC Qingdao Sifang Co.,Ltd.,Qingdao 266311,China;Institute of Welding,School of Materials Science and Engineering,Southwest Jiaotong University,Chengdu 610031,China)
出处
《热加工工艺》
北大核心
2023年第11期144-149,153,共7页
Hot Working Technology
关键词
SMA490BW钢
缺陷深度
补焊
组织
力学性能
SMA490BW steel
defect depth
repair welding
microstructure
mechanical properties