Process Stability, Microstructure and Mechanical Properties of Underwater Submerged-Arc Welded Steel

In underwater wet welding, the unstable welding process caused by generation and rupture of bubbles chilling effect water on area result in low quality welded joints, which makes it difficult to meet practical application marine engineering. To improve stability joining quality, a mixture flux with glass or epoxy resin was placed zone before welding. this paper, welds’ appearance, geometry statistics formation, stability, slag structure, microstructure, pores mechanical properties were investigated. It found that addition mixture, penetration weld effectively increased, frequency arc extinction reduced. Though porosity rose relatively high level, joints’ comprehensive not significantly improved. Notably, applied completely isolated surrounding from area, greatly improved stability. Furthermore, benefited microstructure filled massive acicular ferrite, average elongation room temperature impact toughness increased 178.4%, 69.1% compared respectively, bending angle joint reaches 180°.