The material of the copper valve suitable for the production of bellows must have good plasticity, high elastic limit, tensile strength and fatigue strength, good welding performance, and stable elastic performance. Because of these performance characteristics, austenitic stainless steel is widely used in the manufacture of bellows.
In the metal bellows copper valve, the metal bellows assembly provides an axially movable metal shell between the valve stem and the process fluid in the valve body to form a dynamic seal. The bellows bears the pressure, temperature and corrosion of the medium while bearing the compression and extension of the valve stem, ensuring that the copper valve achieves zero leakage during the life cycle. With the widespread application of bellows in the copper valve industry, the technical requirements for bellows are constantly increasing. The metal bellows for copper gate valves are constantly developing in the direction of high pressure resistance, high temperature resistance, corrosion resistance and long life.
Basic requirements for bellows materials for copper gate valves
The material suitable for the production of bellows must have good plasticity, high elastic limit, tensile strength and fatigue strength, good welding performance, and stable elastic performance. Because of these performance characteristics, austenitic stainless steel is widely used in the manufacture of bellows.
High pressure
Pressure resistance is the basic requirement for copper gate valves and bellows. However, as the pressure level of the copper gate valve increases, the wall thickness and rigidity of the bellows increase, which increases the difficulty of opening the copper gate valve and the manufacture of the bellows. Bellows manufacturers generally do not simply increase the wall thickness, but increase the pressure resistance of the product by increasing the number of layers, while reducing the axial stiffness of the bellows and reducing the opening force of the copper gate valve. The wall thickness of austenitic stainless steel bellows with a nominal pressure below 15MPa (900 lb) is generally 0.1～0.3mm, and the number of layers is 1～6. The bellows under this pressure level has a certain versatility and has formed a series of products. When the pressure reaches 25MPa (1500lb) or more, the appropriate material should be selected according to the diameter of the copper valve and the working temperature, and designed and produced by the professional manufacturer of bellows.