(1)welding materials

　　The welding material directly determines the quality of the welding. In the welding process, materials such as welding rods, welding wires, and shielding gases are used. Therefore, it is very important for the management of welding materials. In the actual management process, there are often some negligence.Due to the negligence of technicians and managers on the quality management of raw materials, the welding materials can not meet the corresponding standards directly, resulting in the welding defects of pressure vessels.

　　(2) The professional level of the welder is not very high

　　For places with high welding requirements, the welding process directly determines the welding quality. At this time, it relies largely on the professional level of the operator to adjust and test the welding parameters according to the welding requirements.

　　For the above analysis, the following defects often occur in the welding process:

　　(A) Undercut of welding.

　　The welded undercut is an external defect of the pressure vessel, that is, different sizes of depressions appear in the welded connection area. This defect is mainly due to the failure to choose a scientific and reasonable welding method during welding. Or, the welding wire is not kept in the same position as the central position during the welding process, so that the welding seam area is exposed to high temperature for a long time, thereby causing defects of undercut.

　　(B) Welding slag.

　　When welding, slag inclusions for welding are unavoidable and cannot be controlled artificially. Once the slag is in the welding seam for a long time, it will form slag inclusion defects, which will affect the tightness and strength of the pressure vessel.

　　(C) Welded air holes.

　　The welded air holes directly affect the tightness and strength of the pressure vessel. The air holes are generated after the molten pool is formed, and the existence of air bubbles is not eliminated before solidification, and then the air holes are generated. The defect of this air hole is mainly due to the fact that the area of the groove is not cleaned of oil and dust.

　　(D) Incomplete penetration and fusion of welding.

　　Incomplete penetration and fusion of welding is very easy to produce cracks, resulting in serious safety accidents. When welding, it often occurs at the beginning and end of welding. Once the metal in this area is not directly fused, the defect of incomplete fusion will occur in this area. This defect is mainly affected by factors such as the arc length being too far from the standard and the electrode diameter being too large.

　　Preventive measures for welding defects of pressure vessels

　　It can be inferred from the analysis of the above welding technology and the characteristics of the defects that any welding quality problems in the pressure vessel will directly affect the performance and strength of the entire pressure vessel, and lay a serious hidden danger to safety production. Therefore, certain precautions need to be taken to ensure the safety and tightness of the pressure vessel. The preventive measures are as follows:

　　1 Improve the professional quality of welding personnel.

　　Due to poor professional skills of welding personnel and improper operation, welding defects often occur. In order to improve the welding quality of pressure vessels, it is necessary to conduct professional skills assessment of welding technicians and obtain a certificate. It is necessary to carry out certain content training. The content of the training needs to be emphasized according to the company's actual situation and working environment. Only after passing the inspection can they be employed.

　　2 Choose scientific and reasonable welding methods, adopt standardized management and strictly implement welding methods.

　　Choosing a scientific and effective welding method can directly determine the welding quality of the pressure vessel. Before starting welding, the operator needs to select the best according to the on-site working environment and welding method, adopt appropriate welding methods, perform statistics and analysis on the welding related data, and select the most effective method. After selecting the welding method, the welding process should be standardized and strictly executed in accordance with the qualified welding process to ensure the quality of the welding.

　　3 Quality management and supervision during the welding process. Before welding, it is necessary to review the preparation for welding. Welding can only be carried out if it meets the standard. Safety must be the first priority.

　　In order to ensure the safety and quality of the pressure vessel, it is necessary to analyze the welding technology and take preventive measures for the existing welding defects. Welding practitioners need to continuously strengthen their professional advancement. Enterprise units need to formulate management systems related to welding work to make welding work more standardized, thereby improving the welding quality and safety characteristics of pressure vessels.