Pneumatic ball valves can be divided into straight through type, three-way type and right angle type according to their channel positions. The latter two ball valves are used to distribute media and change the flow direction of media

Cause Analysis of Corrosion Cracking of Stainless Steel Bellows
As we all know, the basic conditions for stress corrosion cracking of stainless steel are sensitive alloys (material elements), specific media (environmental elements), such as the use of austenitic stainless steel in chloride containing solutions; Certain tensile stress (mechanics,... elements), including external stress, phase transformation stress and residual stress. If these three basic conditions are met, stress corrosion damage of stainless steel may occur. When stress corrosion cracking occurs, it does not occur obvious uniform corrosion, so that there are few corrosion products, and sometimes it is difficult to find with the naked eye, so stress corrosion is a very risky damage. The stress corrosion process can generally be divided into three stages: the first stage is the incubation period. In this stage, due to the localization of the corrosion process and the effect of tensile stress, cracks nucleate, that is, small pits are preferentially formed at the corrosion sensitive parts of stainless steel; The second stage is the corrosion crack development period. When the crack nucleates, under the combined action of the tensile stress in the corrosion medium and metal, the crack expands, leading to the damage of the parts and generating slender cracks; In the third stage, due to the local concentration of tensile stress, the crack grows rapidly, the crack expands quickly, and serious damage can occur in a short time.
Elements of stainless steel ripple affecting stress corrosion:
The stress corrosion cracking of stainless steel is related to the characteristics of medium, temperature and stress, as well as the composition and structure of steel. The impact of these elements is introduced below.
1 Effect of chloride ion concentration Generally speaking, the time required for stress corrosion cracking of Cr Ni stainless steel decreases with the increase of chloride concentration. It is generally believed that M gCl2 is most likely to cause stress corrosion cracking, and the corrosion effect of different chlorides is in the order of Mg2+, Fe3+, Ca2+, Na+, Li+plasma.
2 Effect of medium temperature
It is generally believed that stress corrosion is easy to occur when the temperature rises, but the temperature transition is too high, and stress corrosion is controlled due to overall corrosion. Some steels also have a critical fracture temperature. According to statistics, the temperature range of stress corrosion of Cr Ni austenitic stainless steel is between 50 ℃ and 300 ℃.
3 Effect of alloy elements and stress
It can be seen that the increase of alloying elements nickel and silicon in steel can improve the stress corrosion cracking resistance of austenitic stainless steel in MgCl2 solution, while nitrogen, phosphorus and other elements in steel can reduce the stress corrosion cracking resistance of stainless steel in concentrated chloride medium.