Electrode classification J represents structural steel electrode Z represents a cast iron electrode T represents a special electrode D represents surfacing electrode G stands for chromium stainless steel electrode A representative of stainless steel electrode E stands for welding rod mean Modern pressure vessel structure is basically the welded structure. Welding is the main pressure vessel manufacturing process means one. The electrode welding material is most commonly used. The electrodes can be divided into nine categories according to the different uses and performance. ① structural steel electrode (ordinary low-alloy steel is also included in such): these electrodes deposited metal, has a certain mechanical properties at room temperature in the natural environment. ② molybdenum and chromium molybdenum heat-resistant steel electrode: these electrodes deposited metal, the ability to work with varying degrees of high temperature. (3) stainless steel electrode: these electrodes deposited metal, with varying degrees of resistance to atmospheric corrosion medium corrosion and mechanical properties at room temperature, in the high or low temperatures. ④ surfacing electrode: these electrodes specifically for the surfacing of the metal surface, and having a certain degree of resistance to different types of wear or corrosion, and other properties of the deposited metal in the normal and high temperature. ⑤ Low electrode: these electrodes deposited metal in different cryogenic medium under conditions, it has a certain low-temperature working ability. ⑥ cast iron electrode: these electrodes specially designed for welding or welding cast iron. ⑦ nickel and nickel alloy electrode: these electrodes for nickel and aluminum alloy welding, repair welding or surfacing. Some electrodes can also be used for cast iron welding and welding of dissimilar metals. ⑧ copper and copper alloys: these electrodes for copper and copper alloy welding, welding or surfacing. Some cast iron welding and welding of dissimilar metal electrodes can be used. The ⑨ aluminum and aluminum alloys: these electrodes for aluminum and aluminum alloy welding, repair welding or surfacing.