What's the use of welder's certificate?

They are welder qualification certificate and welder grade certificate.

The certificate of professional qualification grade, issued by the labor bureau, is an essential certificate for promotion, salary increase and professional title. The salary of senior is 200-500 higher than that of junior high school, which is divided into five levels: mechanic and technician, and the certificate is common throughout the country.

Welders will cause pathological changes in blood, eyes, skin and lungs during operation. In welding, welders are often harmed by strong light, infrared rays and ultraviolet rays. X-rays produced by electron beam in welding will affect the health of welders.

During welding, the metal, covered electrode coating, dirt, paint, etc. at the welding site. Evaporation or combustion due to high temperature, forming smoky steam dust, leading to poisoning.

Extended data:

The arrangement of welds shall avoid the joint overheating caused by dense, crossed or excessively concentrated welds, increasing the heat affected zone, deteriorating the structure and seriously reducing the performance. The distance between two welds is generally required to be greater than 3 times the thickness of the plate.

Avoiding welding joints in large stress areas and stress concentration areas is the weak link of welded structures. Therefore, the weld layout should avoid the parts with high stress on the welded structure. In addition, under concentrated load, the weld should have rigid support.

When welding away from the machining surface, the workpiece will be deformed. For welded structures with high position accuracy, they should be trimmed after welding. For welded structures with low position accuracy requirements, mechanical processing can be carried out first, but the weld position should keep a certain distance from the machined surface.

Baidu Encyclopedia-Welding Certificate

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