Experimental research on welding materials of Dalian marine parts under different heat treatment conditions most structural products need annealing stress relief after welding, and some need tempering or normalizing. It is hoped that the welding material manufacturer should also carry out experimental research under different heat treatment conditions to meet the needs of different structures. When the shortage of special welding materials involves the welding of weldox960 and other high-strength steels, only imported high-strength steel welding materials can be purchased, which has high cost and long supply cycle. It is hoped that domestic welding material manufacturers will devote more efforts to the research of high-strength steel welding materials and develop mature industries. In addition, the localization research of heat-resistant steel welding wire, low-temperature steel welding wire, atmospheric corrosion-resistant steel welding wire and stainless steel welding wire is conducted. For the effective inspection method of cylinder leakage, the commonly used method is water pressure inspection. When the hydraulic test method is used for inspection, first install the gasket of the cylinder head on the cylinder block. Except for leaving a small hole to connect with the water pipe of the press, all other water channels and holes shall be blocked. When everything is ready, turn on the switch of the hydraulic press and keep it under the pressure of 200kpa~392kpa for about 3 minutes to determine the size and location of the crack.