The core contradiction of K500 welding lies in the damage caused by the welding heat cycle to the aging strengthening effect. During the welding process, the temperature of the weld seam and the heat-affected zone exceeds the aging temperature, and the already precipitated Ni₃(Al, Ti) precipitate phase re-dissolves, resulting in a significant decrease in the strength of this area. The countermeasures are as follows: The welding should be carried out in the solution state, and after welding, a solution treatment should be performed first to homogenize the structure, followed by aging treatment to restore the strength. If welding is directly performed in the aging state, the heat-affected zone will be in an over-aged or solution state, and cannot be completely restored through simple post-weld heat treatment. The welding method should preferably choose a low heat input process (such as TIG), control the interlayer temperature, and reduce the width of the heat-affected zone. Stress elimination treatment should be carried out before post-weld aging to prevent deformation during the aging process. The corrosion resistance of the weld seam is usually equivalent to that of the base material, but attention should be paid to that welding defects (gas pores, incomplete fusion) may become the starting point of corrosion.
Jiangsu Cunrui Metal Products Co., Ltd. We supply solidified K500 bar materials suitable for welding processing, and can provide information on heat treatment status. If you need welding materials, please feel free to contact us.