Gas welding or electric welding can be filled at the joint of the welding workpiece. According to the provisions of the national standard "welding steel wire" (GB 1300-77) classification, special steel wire for welding can be divided into carbon structural steel, alloy structural steel, stainless steel three categories. The selection of welding electrode must be in the premise of ensuring the safety of the welding structure, feasible use, according to the chemical composition of the welding material, mechanical properties, plate thickness and joint form, welding structure characteristics, stress state, structural conditions on the requirements of weld performance, welding construction conditions and technical and economic benefits, targeted selection of welding electrode, if necessary, also need to carry out weldability test. In addition to meeting the general welding process performance and mechanical properties of welded joints, stainless steel welding rods should also ensure that the welded joints can meet certain corrosion resistance requirements. For the coating and welding core, the following requirements are usually taken into account: 1) Through the welding core and the coating transition various alloying elements, so that the weld metal becomes a certain amount of austenite and ferrite structure, to ensure that the weld metal has good crack resistance and good resistance to the corresponding medium corrosion. 2) Through the welding core or coating, the weld metal can penetrate a certain amount of carbide forming elements (such as niobium, molybdenum, titanium, etc.), and form a stable carbide with carbon to prevent the grain boundary from generating chromium carbide. 3) The increase of carbon will promote the intergranular corrosion of Austenitic stainless steel (or ferritic stainless steel) weld, so the carbon content in the welding core and coating raw materials should be strictly controlled, it is recommended to use low-carbon or ultra-low carbon welding core, the use of low-carbon or carbon-free ferroalloy and metal elements as raw materials for coating.