Welding process measures

1. Can be preheating to reduce the probability of cold crack, preheating and inter-channel temperature requirements control between $number, after welding heat treatment in 620~690, heat preservation 1 hours, in order to ensure the weld metal strength, at 620 temperature tempering not to go to 30h, otherwise reduce tempering temperature The weld heat treatment can not only eliminate welding residual stress, but also improve the microstructure and improve the mechanical properties of the joints.

2. The use of less welding line energy welding, to prevent excessive martensite hardening tissue generation;

3. The use of argon-rich gas protection for Jet transition welding (ARC length control in the 4mm~5mm around), to obtain a beautiful weld.