① different strength of carbon steel + low alloy steel (or low alloy steel + low alloy high strength steel), the general requirements of the weld metal or joint strength of not less than the minimum strength of two kinds of metal was welded, the choice of welding metal Should ensure that the strength of the weld and joint is not lower than the strength of the base metal, and the plasticity and impact toughness of the weld metal should not be lower than the strength and the plasticity of the base metal. Therefore, according to the strength of the lower level of steel selection of electrodes. However, in order to prevent welding cracks, should be higher strength level, poor weldability of steel to determine the welding process, including welding specifications, preheating temperature and post-weld heat treatment. The same time as
② low alloy steel + austenitic stainless steel, should be based on the chemical composition of the deposited metal to limit the value of the choice of electrodes, the general use of chromium and nickel content of higher plasticity and good crack resistance Cr25-Ni13 austenite Steel electrodes to avoid cracks due to brittle hardening. But should be poor welding stainless steel to determine the welding process and specifications.
③ stainless steel composite plate should be considered on the grassroots, multiple layers, the transition layer of the welding requirements of the use of three different performance of the electrode. On the base layer (carbon steel or low alloy steel) welding, the choice of the corresponding strength grade of the structural steel electrode; layer directly contact with the corrosive medium, should use the corresponding composition of austenitic stainless steel electrode. The key is the transition layer (ie, the interface with the grass-roots interface) of the welding, we must consider the dilution of the matrix material should be used chromium and nickel content is higher, plastic and crack resistance Cr25-Ni13 austenitic steel electrode.