304不锈钢水下局部干法TIG点焊工艺

Underwater local dry TIG welding of 304 stainless steel

为实现上堆芯板定位销的水下原位修复,文中开展了304不锈钢水下局部干法TIG焊接工艺研究,并分析了焊接工艺参数对焊接质量的影响。试验结果表明,定位销模拟件水下焊接获得的焊点成形较好,无显著氧化及表面缺陷存在。随着焊接电流和焊接时间的增加,焊点截面尺寸亦显著增加,导致焊点压缩承载力逐渐增大。焊点焊缝区由γ-奥氏体和少量δ-铁素体组成,而热影响区由于热循环作用导致晶粒显著粗化。基于焊接效率和焊点力学性能,2号焊接工艺参数能够实现对定位销模拟件的优质连接,对于水下焊接修复具有重要意义。

In order to realize the underwater in-situ repair of the upper core plate locating pin,this paper conducted the underwater local dry TIG welding process of 304 stainless steel,and analyzed the influence of welding process parameters on welding quality.The test results show that the shape of the weld joint obtained by underwater welding of the positioning pin simulator is good,and there are no significant oxidation and surface defects.With the increase of welding current and welding time,the cross-section size of the solder joint also increases significantly,resulting in the gradual increase of the compression property of the solder joint.The weld area of the welding spot is composed ofγ-Austenite and a small amountδ-Ferrite.Grain coarsening in the heat affected zone due to thermal cycling also existed.Considering the welding efficiency and mechanical properties of the solder joint,No.2 welding process parameters can realize the high-quality joining of the locating pin simulated sample,which is of great significance for underwater welding maintenance.