SAF2205双相不锈钢多层多道焊接头的组织及性能  

Study on microstructure and comprehensive properties of SAF2205 duplex stainless steel multilayer and multipass welded joint

作　　者：李亚杰[1] 刘瑞 秦凤明 马承睿 LI Yajie;LIU Rui;QIN Fengming;MA Chengrui(Taiyuan University of Science and Technology,Taiyuan 030024,China)

机构地区：[1]太原科技大学,太原030024

出　　处：《焊接学报》2023年第6期74-81,I0007,I0008,共10页Transactions of The China Welding Institution

基　　金：山西省自然科学基金项目(202103021224282和202103021223288)。

摘　　要：采用TIG/PAW复合焊接对SAF2205双相不锈钢进行多层多道焊接,并进行固溶处理,利用OM、SEM、EBSD等设备,通过电化学腐蚀、拉伸、冲击等试验研究焊缝组织演变与综合性能的关系.结果表明:TIG填丝盖面焊接处的焊缝铁素体含量为70.5%,由于添加焊丝的原因,焊缝奥氏体晶粒最大为177μm^(2),大于母材142μm^(2);PAW焊缝铁素体含量为65.4%,因为焊接顺序的不同,后续焊接对焊缝有加热作用,导致铁素体含量最少;在TIG焊缝中,热输入较大,导致铁素体晶粒粗化最大为8147μm^(2),大于母材264μm^(2),导致奥氏体形核位置减少,奥氏体仅为3.96%.在1050℃固溶处理60 min后焊缝两相接近1∶1,并且奥氏体趋于均匀化,随固溶时间的延长耐腐蚀性增强.焊态焊缝抗拉强度大于846 MPa,拉伸断裂均在母材.焊缝冲击吸收能量为144 J,小于母材(156 J),焊缝表现为复合断裂.TIG/PAW composite welding was used to weld SAF2205 duplex stainless steel with three layers and three channels,and solution treatment was carried out.OM,SEM,EBSD and electrochemical corrosion,tensile,impact and other experiments were used to study the relationship between the microstructure evolution of the weld and mechanical properties,corrosion resistance.The results show that the ferrite content of TIG filler wire weld is 70.5%,and the austenite grain of TIG filler wire weld is the largest(177μm^(2)),which is larger than that of base metal(142μm^(2))due to the addition of welding wire.The ferrite content of PAW weld is 65.4%.Due to the different welding sequence,subsequent welding has a heating effect on the weld,resulting in the least ferrite content.In TIG weld,the large heat input results in the coarsening of ferrite grain(8147μm^(2)),which is larger than the base metal(264μm^(2)),resulting in the reduction of austenite core location and only 3.96%austenite.Due to the difference of deformation mechanism and stacking fault energy between austenite and ferrite,the number of ferrite sub-grains is larger than that of austenite,while the number of recrystallized grains and high-angle grain boundary is smaller than that of austenite.After solution treatment at 1050℃for 60 min,the two phases of the weld are close to 1∶1,and the austenite tends to homogenize,and the corrosion resistance increases with the extension of solution time.The tensile fractures were all in the base metal,and the tensile strength of the weld were greater than 846 MPa.The weld impact energy is 144 J,less than the base metal(156 J),and the weld shows composite fracture.

关 键 词：SAF2205双相不锈钢 复合焊接TIG/PAW 微观组织 固溶处理 综合性能 

分 类 号：TG457.11[金属学及工艺—焊接]