Stainless steel U-tube processing process and matters needing attention

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.

(1) Choose better tap material. The wear resistance and toughness of tap can be improved by adding special alloying elements into ordinary high speed tool steel.

(2) The wear resistance, heat resistance and lubricity of tap can be significantly improved by coating the surface of tap thread with titanium nitride coating.