用 N_2 背面保护焊接奥氏体钢管

On the welding of austenitic stainless steel pipes backpurged with nitrogen

研究了采用ＴＩＧ焊技术焊接１Ｃｒ１８Ｎｉ９Ｔｉ钢管子时，以Ｎ２代替Ａｒ背面保护焊缝的组织和性能，分析了根部焊缝表层中的Ｎ和Ｏ元素的分布，测量了焊缝中的δ－铁素体、Ｎ和Ｏ的含量．研究结果表明：Ｎ２可以代替Ａｒ背面保护１Ｃｒ１８Ｎｉ９Ｔｉ钢焊缝，焊缝表层的Ｎ，Ｏ的分布和焊缝中的δ－铁素体、Ｎ和Ｏ的含量无明显变化，焊接接头性能良好．

Investigation was carried out on the microstructrues and properties of the 1Cr18Ni9Ti pipe joints backpurged with nitrogen instead of argon in TIG welding. The distribution of nitrogen and oxygen elements in the surface layers of the root weld metals was analysed by WDS. The contents of δferrite, nitrogen and oxygen in the weld metals were measured. The study reveals that nitrogen can be used to replace argon for backpurging in the austenitic stainless steel pipe welding without any adverse effects on the properties of the joints, and an excellent purging can be obtained.