Abstract: Aiming at the challenges in welding stainless steel rail heads to the main rail embedded parts of the inlet gate at bottom outlet for sediment flushing at Baishuiyu hydropower station, which at a water depth of 38 meters, experiments including welding electrode selection and construction condition simulation in the high- pressure training cabin were carried out to optimize welding parameters and verify equipment. The results showed that the joint strength of both wet welding and dry welding met the design requirements. In practical construction, the process of "taking high-pressure dry welding as the main method and local wet welding as the auxiliary method" was adopted. The independently designed and manufactured local dry welding chamber can ensure welding quality, high efficiency and operation safety.

Key words: dissimilar steel, underwater wet welding, underwater high-pressure dry welding, local dry welding chamber, stainless steel welding electrode

摘要： 针对白水峪水电站拉沙底孔进口闸门主轨埋件在水下38 m贴焊不锈钢轨头的异种钢焊接难题，通过焊条筛选、高压训练舱内模拟施工条件等试验，进行了焊接参数优化及装备验证，结果表明湿法焊接和干法焊接的接头强度均满足设计要求。采用“高压干法为主、局部湿法为辅”工艺，自主设计、制作的局部干法工作罩能保证焊接质量，效率高，并确保作业安全。

关键词: 异种钢材, 湿法水下焊接, 水下高压干式焊接, 局部干法工作罩, 不锈钢焊条