What matters should be paid attention to in the selection of welding materials for boilers and pressure vessels?

1. Welding materials for welding pressure vessels include electrodes, wires, steel strips, fluxes, gases, electrodes and gaskets.

2. Selection principle of welding materials: According to the chemical composition, mechanical properties and welding properties of the base metal, and combined with the structural characteristics, operating conditions, welding methods and manufacturing processes of the pressure vessel, the welding materials are selected comprehensively, for example:

①For welded joints under stress and pressure, the welding materials should first be selected according to the principle of joint strength;

②For the welded structure working at low temperature, the low temperature toughness of each area of ​​the joint should be guaranteed first, which is more important than the joint strength;

③ For containers with only corrosive medium, first ensure the corrosion resistance of the parts where the inner wall of the container is in contact with the medium;

④ Secondly, consider the processing technology of the welded structure, such as shearing, cold stamping, cold coiling, hot coiling and the influence of various heat treatment processes on the performance of the joint (cold stamping, shearing and cold coiling and other processes require welded joints with high Plastic deformation ability; while hot coil and heat treatment process, the joint is required to maintain the specified strength and toughness after high temperature heating);

⑤Finally, the influence of thermal cycle and metallurgical characteristics of various welding methods on joint performance is considered.