Pump valve casting in the process of processing with high surface finish and dimensional accuracy, so the process can reduce the machining of its work, but the parts require a higher position to leave a little allowance, Even some of the castings only grinding, polishing margin, without machining can be used.
Pump valve casting general process:
1. The pump valve casts an effective alloy grade as specified by its casting technology requirements so that the chemical composition of the alloy can be found and the chemical composition selected.
2. Valve Casting According to the elements of the burning rate and composition requirements, the ingredients calculated to draw a variety of charge of the charge, and select the charge. If the charge is contaminated, it will need to be processed to ensure that all charges are clean, rust-free and preheated before charging.
3. Check and prepare the utensils, brush the paint, and preheat, to prevent the gas, inclusions and harmful elements of pollution.
4. In the process of feeding the general order of charge back, the middle alloy and metal materials, low melting point easily oxidized metal material, such as magnesium, after the charge is melted to join.
5. In order to reduce the intake of liquid alloy and oxidation of pollution, should be melted as soon as possible to prevent overheating, according to the need, some alloy liquid plus cover agent protection.
After the charge is melted, it is refined to purify the alloy liquid and test the refining effect.
7. If necessary, modify and subdivide the tissue to improve the performance and check the treatment effect.
8.Adjust the temperature, pouring. Some alloys in the casting before mixing, to prevent the proportion of segregation.
Pump valve casting process:
1. The pump valve casting softening annealing its main purpose in the use of the decomposition of carbide, the effective reduction of its hardness, so that it can effectively improve its processing performance, ductile iron, the purpose is to get more Ferritic tissue.
2. Valve casting normalizing, the main purpose is to obtain pearlite and sorbite to improve the mechanical properties of castings.
3. Quenching mainly in order to obtain higher hardness or wear strength, while getting very high surface wear characteristics.