As an important part of the petrochemical pipeline system, valves play an important role in the petroleum refining and processing process. In the petrochemical industry, ethylene plant, polyethylene plant (LLDPE linear low-density polyethylene, HDPE high-density polyethylene), polypropylene plant, butadiene device, EO/EG ethylene oxide/ethylene glycol, gasoline hydrogenation plant, PX hydrocarbon aromatic combined plant, MTBE/butene-1 device in the valve use of most of the media have flammable, explosive, toxic and corrosive characteristics, and the process is complex, the process conditions are harsh, the start cycle is required, and the valve fails in production. The light ones cause medium leakage and pollute the environment, and the heavy ones cause fires and explosions, causing malignant accidents to bring losses to the safety of people's lives, so the quality requirements for valves in petrochemical refining and chemical production are high.