Molybdenum and chrome molybdenum heat resistant steel electrodes are one of low alloy steels. It has a certain heat resistance in the working temperature range of 500 to 600 °C. In general, the welding performance of pearlitic heat-resistant steel is similar to that of low-alloy steel. Only in the chemical composition of the weld, the pearlitic heat-resistant steel should be strictly controlled. Before this steel welding, most of the weldments need to be preheated to prevent the formation of weld cracks; post-weld heat treatment to eliminate the brittleness and weld residual stress of the welded joint.