Welding procedure qualification is an important measure to ensure quality, which provides a reliable basis for formally formulating welding procedure instruction or welding procedure card. It can confirm the correctness and rationality of the welding procedure specification for various welding joints. Welding, also known as fusion, is a manufacturing process and technology to connect other thermoplastic materials such as metal or plastic by heating, high temperature or high pressure. For the manufacture and installation of products, the welding process should be evaluated before the formal welding work begins, that is, whether the welding process meets the requirements. The scope of application of welding procedure qualification includes the manufacture, installation and maintenance of spacecraft, ships, nuclear energy, load-bearing steel structures, bridges, pressure vessels, pressure pipelines, boilers and other steel equipment.