氮在不锈钢GMAW电弧中的过渡规律及对焊缝组织和性能的影响  

Transition of Nitrogen During the GMAW Process and Its Effects on the Microstructure and Properties of Stainless Steel Joint

作　　者：程尚华 李方亮 张一琪 武少杰 程方杰 CHENG Shanghua;LI Fangliang;ZHANG Yiqi;WU Shaojie;CHENG Fangjie(School of Materials Science and Engineering,Tianjin University,Tianjin 300350,China;Tianjin Key Laboratory of Advanced Joining Technology,Tianjin 300350,China)

机构地区：[1]天津大学材料科学与工程学院,天津300350 [2]天津市现代连接技术重点实验室,天津300350

出　　处：《材料导报》2023年第18期159-164,共6页Materials Reports

基　　金：国家自然科学基金(51775372)。

摘　　要：在不锈钢熔化极气体保护焊(GMAW)中,通过向保护气中加入定量的N_(2)实现了对焊接接头组织和性能的精确调控。结果表明,增加保护气中的N_(2)含量、减小送丝速度或者提高焊接电压都会使得熔覆金属中的N含量升高,同时铁素体数(FN)减少;经典的WRC-1992相图无法精确地预测多层焊熔覆金属的FN,在FA凝固模式下焊缝金属的FN预测值比实测结果低约2.7;在保护气中添加10%的N_(2),可以在保证FA凝固模式不变的同时,精确地控制铁素体数在3.0左右,同时接头的耐点蚀性能显著提升。与前期的GTAW添加N_(2)的结果对比发现,GMAW工艺下N元素更难向熔池过渡,需要添加的N_(2)量约为前者的10倍。In this research,the microstructure and properties of the stainless steel joint were accurately controlled by adding certain amount of N_(2)to the shielding gas of the gas metal arc welding(GMAW)process.The increase of the N_(2)addition,the decrease of the wire feeding speed and the raise of the welding voltage promoted the transition of elemental N from the arc to the deposition metal and resulted in the decrease of the ferrite number(FN)of the joint.It was also proved that the WRC-1992 diagram could not give an accurate prediction of the FN of the multi-pass stainless steel joint that the predicted FN of the deposition metal solidifying as type FA was about 2.7 lower than the measured FN.By adding 10%N_(2)to the shielding gas,the multi-pass stainless steel joint remained solidifying as type FA and its FN was successfully controlled to about 3.0,which significantly improved its pitting corrosion resistance.The transition of element N was significantly harder in GMAW process than in gas tungsten arc welding(GTAW)process,thus about 10 times of N_(2)should be added to the shielding gas of GMAW process to promote the N transition.

关 键 词：奥氏体不锈钢 熔化极气体保护焊 熔覆金属N含量 耐点蚀性能 

分 类 号：TG444[金属学及工艺—焊接]