Characteristics of valve manufacturing process

Ball Valve manufacturing process is extremely complex and high technical difficulty. On the surface, the number of valve parts is small, the structure is simple, the accuracy requirements are general, and it is a relatively simple part in the mechanical industry. However, the manufacture of the core sealing part of the valve is extremely demanding, and a zero-to-zero sealing fit must be achieved in order to meet the zero leakage requirements of the airtight test. Therefore, the valve manufacturing process is actually quite complex, and the technical difficulty is also very large, with the following characteristics:
① Material selection is demanding.
Due to the wide range of applications, valves need to be used in high temperature and high pressure, low temperature and deep cooling, flammable and explosive, highly toxic, strong corrosion and other harsh conditions, which puts forward extremely high requirements for materials. In addition to commonly used cast iron, carbon steel, etc., but also widely used stainless steel, alloy steel, titanium alloy and other high alloy materials. The casting, welding and processing properties of these high alloy materials are poor, which brings great difficulties to the manufacturing process.
② The casting process is complex.
Most valves use thin shell castings with complex structure, not only the appearance of high quality requirements, internal quality and metallographic structure must also reach a high standard, there can be no porosity, shrinkage and other defects. Therefore, the casting process is much more complex than the general mechanical parts.
③ Machining is difficult.
Most of the high strength, high hardness, high corrosion resistance of the valve material cutting performance is poor, it is difficult to achieve the required dimensional accuracy and finish. In addition, the processing accuracy, matching Angle and finish of the valve sealing surface are also very high, which brings great challenges to machining.
④ Valve parts in the machine tool clamping is also more difficult.
Valve main parts such as valve body, gate and other structure and shape is more complex, some parts are thin-walled, slender parts, poor rigidity, in the machine tool processing positioning and clamping are more difficult, need to use more complex special fixture.
⑤ The process arrangement is complex.
On the surface, the number of valve parts is small and the structure is simple, but the "three degrees "(flatness, finish, hardness) of the core sealing part are extremely high, and the anastomosis of the two sealing surfaces must reach zero to zero. This requirement to ensure precision seal with rough reference is the biggest process difficulty of valve manufacturing.
⑥ Test inspection hidden dangers.
As the opening and closing and regulating elements of pressure pipelines, valves need to be used in various harsh working conditions. However, the test and inspection can only be carried out under normal temperature conditions, which cannot completely simulate the actual working conditions, and there are major hidden dangers.