单双面MAG焊对304不锈钢单卷边T形接头组织及性能的影响  

Effect of single-side and double-side MAG welding on microstructure and properties of single-side crimpexd T-joints of 304 austenitic stainless

作　　者：刘吉华 于丕桀 欧洋婷 陈鹏 陈世涛 徐志彪 何成刚 LIU Jihua;YU Pijie;OU Yangting;CHEN Peng;CHEN Shitao;XU Zhibiao;HE Chenggang(School of Railway Tracks and Transportation,Wuyi Universiy,Jiangmen 529020,Guangdong,China)

机构地区：[1]五邑大学轨道交通学院,广东江门529020

出　　处：《焊接》2025年第1期54-63,共10页Welding & Joining

基　　金：广东省基础与应用基础研究基金资助项目(2019A1515110807)。

摘　　要：【目的】旨在探究单双面焊接对单卷边T形接头力学性能的影响。【方法】采用熔化极活性气体保护电弧焊(MAG焊)方法实现对SUS304奥氏体不锈钢单卷边T形接头的单面和双面焊接,其中焊丝材料选用308L Si不锈钢,探讨分析焊接过程中焊接接头金属的凝固结晶模式,研究其显微组织和力学性能,并对其结构进行静力学有限元分析。【结果】利用MAG焊对SUS304奥氏体不锈钢焊接可获得性能优异的焊接接头,焊接接头不同区域的凝固模式不受焊接道次的影响。【结论】由于温度梯度的变化和元素的偏析,焊缝(Weld metal,WM)、熔合区(Fusion zone,FZ)、半熔化区(Partially molten zone,PMZ)的凝固模式分别是FA(Ferritic-austenitic),FA/F(Austenitic-ferritic/ferritic),AF(Austenitic-ferritic)模式,焊接接头的焊缝和半熔化区组织主要由柱状奥氏体和少量条状铁素体组成,熔合区铁素体组织则呈现出针状,铁素体不同的形态与区域的冷却速度有关。单面焊接和双面焊接获得的焊接接头抗拉强度均与母材一致,但拉伸应力集中在不同区域,单面焊接接头易集中在熔合区,双面焊接接头易集中在直板母材处。[Objective]The aim is to investigate influence of single-side and double-side welding on mechanical properties of single-side crmpexed T-joints.[Methods]MAG(Metal active gas arc)welding method is utilized to weld single-side crimped T-joints of SUS304 austenitic stainless steel with single-side and double-side welding,and 308L Si stainless steel is selected as welding wire.The solidification and crystallization modes metal of welded joints in the welding process are discussed and analyzed,as well as microstructure and mechanical properties.Moreover,stress and strain of welded joints under tensile state are analyzed by finite element method.[Results]By utilizing MAG welding of SUS304 austenitic stainless steel,welded joints with excellent properties can be obtained,and solidification modes of different areas of weld joints are not affected by welding passes.[Conclusion]Due to change of temperature gradient and element segregation,solidification modes of WM(Weld metal),FZ(Fusion zone)and PMZ(Partially molten zone)are FA(Ferritic-austenitic),FA/F(Ferritic)and AF(Austenitic-ferritic)modes,respectively.The microstructures of WM and PMZ of welded joints are mainly composed of columnar austenite and lathy ferrite,and microstructure of FZ acicular ferrite.The tensile strengths of welded joints obtained by single-side welding and double-side welding are almost equal to that of BM,however,tensile stress is concentrated in different areas,thus resulting that single-side welded joints tend to concentrate at FZ,while double-side welded joints are prone to concentrate at BM.

关 键 词：熔化极活性气体保护电弧焊 凝固模式 焊接道次 奥氏体不锈钢 T形接头 

分 类 号：TG444[金属学及工艺—焊接]