Technical requirements of valve manufacturing process for valve design

As the process of valve manufacturing is one of the important contents of product design, the process of valve manufacturing must put forward the requirements of the process of valve design. The main technical requirements are as follows:

1) Casting

① The reasonable structure should be considered according to the characteristics of different materials. For example, due to the large volume shrinkage of malleable iron castings and the need for toughening heat treatment, the size and thickness of castings should be as small as possible; while the fluidity of stainless steel castings is poor, the thickness selected for design should be appropriately increased, and the shape should be as simple as possible.

② The wall thickness should be uniform as far as possible, and there should be arc and necessary slope at the joint to ensure smooth transition, and excessive metal accumulation should be avoided as far as possible, so as to avoid shrinkage, porosity, cracks and other defects.

③ The hollow knife at the bottom of the valve body should not be too narrow or too deep. In order to make the sand core have a certain strength, the circular radius of the hollow knife should not be less than that determined by the valve diameter as far as possible, so as to avoid the difficulty caused by crushing the core sand during pouring.

④ When determining the minimum wall thickness of the valve body, not only the strength and rigidity should be calculated, but also the casting conditions and casting methods of the manufacturer should be considered, so as to achieve good quality, light weight and material saving.

⑤ It is necessary to consider the convenience of mold lifting.

2) Forging

① The shape of forgings should be as simple as possible, and die forgings should be used for large quantities of parts.

② There should be appropriate draft angle, and try to avoid sharp corners and edges.

3) Heat treatment

① The requirements for heat treatment should be reasonably selected according to the characteristics of materials, such as hardness and mechanical properties, and a reasonable range should be specified.

② The rigidity of the parts which are easy to deform during heat treatment should be strengthened properly.

4) Surfacing, mechanical down and assembly

① The weldability of base part and surfacing material should be considered to avoid cracks and other defects. At the same time, the appropriate rough size should be selected.

② There should be positioning datum for easy clamping and adding.

③ It should be easy to measure, and make the design datum and the added measurement datum consistent as far as possible.

④ The design should create conditions for the selection of standard cutting tools, standard fixtures and standard measuring tools, so as to reduce the number of self-made processing equipment.