Stainless steel U-pipe welding before and after the need to pay attention to what aspects??

When welding stainless steel U-shaped tube, mainly because of its strong dendrite directivity, linear expansion coefficient, welding cooling shrinkage stress, easy to appear hot crack, and deformation tendency. In production, the measures to prevent the hot crack of stainless steel U-shaped pipe include: welding austenitic stainless steel U-shaped pipe with welding rod with austenitic ferrite duplex structure; Low hydrogen electrode is used to refine the weld metal crystal, reduce harmful impurities in the weld and improve the crack resistance of the weld. Take as fast as possible welding speed, wait for the stainless steel U tube welding layer after cooling, then weld the next line, in order to reduce the weld overheating; Stainless steel U-shaped pipe welding end or interrupt, arc to slow, fill arc pit, prevent arc pit crack; Use a smaller welding current. When the butt weld and heat affected zone of stainless steel U-shaped tube are kept at 450 ~ 850℃ for a certain time, Cr carbide may precipitate at grain boundary and intergranular corrosion tendency occurs.