Pump valve fittings are very important. They contact the medium during the use of the valve and have relative frictional movement with the packing. Therefore, the valve stem is required to have certain corrosion resistance and scratch resistance. Therefore, in addition to the need to select a certain material and perform the corresponding heat treatment, the valve stem still needs a certain surface treatment.
Pump valve fittings can be used in a variety of surface treatment methods, such as chrome plating, electroless nickel plating, nitriding, etc. Nitriding is a common surface treatment method. Compared with the coating, the nitriding cost is low, the industrial pollution is small, and it is not easy to delaminate when used. Therefore, the manufacturer should vigorously adopt the nitriding process for the valve stem. The carbon steel stems of low pressure valves are now generally nitrided and work well.
When servicing pump valve fittings, it is required to be carried out in a clean environment. First clean the outer surface of the valve, or blow it with compressed air or with kerosene. Then disassemble the other parts of the valve and clean it with kerosene; carry out the strength test on the valve body valve cover; the sealing of the valve valve fitting seal can be checked by red powder, the valve seat and the gate). Check the stem for bending, corrosion, and thread wear. Check the stem nut for wear.www.dmgcastings.com