Imperfect welding process of bellows globe valve: after investigation, the welding process of bellows is not clear, which leads to nonstandard welding process. For example, before welding, the bellows was not fixed with coaxial tooling, resulting in different axes between bellows and valve inner cavity, nonstandard groove of weldment, etc., and wet cloth was not used to protect bellows during welding. Therefore, this factor is the main reason for the high failure rate of bellows.

 Improper way of handling and storing valves: after investigation, the technical requirements for handling and storing bellows are not clear, which leads to the damage of bellows during handling and storing. For example, improper handling method of the valve leads to bending damage of the valve bellows, and there is no protective measure outside the valve bellows, which leads to accidental damage of the bellows, etc. Therefore, this factor is the main reason for the high failure rate of bellows.