2. The hardening and surface treatment of the sphere The pneumatic ball valve sphere is generally processed by 2Cr13, and its surface hardness is about HB217, which is easy to be damaged not only in working conditions, but also in the process of assembly and testing. Our company adopts solid chromizing process for test, which has been proved to be very effective after one year's practice. After chromizing, the surface hardness is higher than HV1000 degrees. After the carbon steel ball is infiltrated, the surface chromium content is as high as 60% - 80%. After grinding, the corrosion resistance in seawater, nitric acid, acetic acid and other media exceeds that of the impermeable 2Cr13 3. Modification and modification of sealing seat For general pneumatic ball valves, the sealing seat is generally made of pure PTFE, and its wear resistance is very poor. The company has carried out filling exploration, and finally developed an enhanced PTFE after dozens of formula tests, tests and screening. Its normal temperature compressive strength can reach 289KG/CM2, which promotes the improvement of the quality of our products.

Stability of bellows
When the bellows is subjected to axial pressure beyond its support, it will suddenly bend and lose the stability of linear form, just like the compression bar or cylindrical spiral spring. This is inevitable. If the internal pressure accepted by the bellows also exceeds a certain pressure value that it can support, instability will also occur. It has been proved that the destruction of bellows in engineering is mostly caused by this reason. Such problems exist in elastic seals, axial expansion compensators and pneumatic butterfly valves.
That is to say, the ability of bellows to accept internal pressure generally depends on its stability. Studying the stability of bellows can use the well-known Euler pressure bar formula! Calculate the critical load.
In this way, the critical load of bellows can be approximately solved by calculation. However, due to the following two reasons, the calculated value usually exceeds the practical value. Details are as follows.
First, the axis of the bellows often deviates from the original axis of symmetry due to the processing deviation of the dimensions of the bellows and the thickness of the data. In other words, the axis of the practical bellows has some initial curvature. As for pneumatic butterfly valves, the unevenness of mesh sleeve weaving and the non divergence of local strength also limit the load-carrying ability of bellows.
Second, since the bending stiffness value in the critical load formula is definitely considered as the semi-circular arc of the wave crest (valley) of the bellows as the rigid connection point of the diaphragm, it is higher than the practical bending stiffness value itself.