What are the cast iron valves? First of all, it should be clear that it refers to the material of the valve body. Cast iron is a general term, and cast iron valves can be divided into: grey cast iron valves, ductile iron valves, and nickel cast iron valves.

⑴Grey cast iron valve
It is suitable for water, steam, petroleum products, and ammonia. It can work in the vast majority of alcohols, aldehydes, ethers, ketones, greases and other less corrosive media. It is not suitable for hydrochloric acid, nitric acid and other media, but can be used in concentrated sulfuric acid, because concentrated sulfuric acid can produce a passivation film on its metal surface to prevent the corrosion of concentrated sulfuric acid to cast iron.
Grey cast iron valves include: grey cast iron butterfly valve, grey cast iron gate valve, grey cast iron check valve, grey cast iron ball valve, grey cast iron globe valve, etc.

(2) Ductile iron valve
It has strong corrosion resistance and can work in a certain concentration of sulfuric acid, nitric acid, sulfuric acid and acid salt. However, it is not resistant to the corrosion of hydrofluoric acid, strong alkali, hydrochloric acid and hot solution of ferric chloride. When using, avoid sudden heating and sudden cooling, otherwise it will break.
Ductile iron valves include: ductile iron butterfly valve, ductile iron gate valve, ductile iron check valve and so on.
Ductile iron grades have advantages in both strength and hardness compared to grey cast iron grades. The tensile strength of ductile iron is 60k, while the tensile strength of gray cast iron is only about 30k. The yield strength of the ductile iron material is 40k, while the yield strength of the gray iron material is not shown, and the fracture phenomenon occurs at the end. Therefore, the tensile strength of ductile cast iron valves is better than that of grey cast iron valves.
At present, in low-pressure water system pipelines, valves made of ductile iron have advantages in terms of use and cost. More and more customers choose to use valves made of ductile iron.

(3) Nickel cast iron valve
The alkali resistance is stronger than that of gray cast iron and ductile iron valves. It is used in dilute sulfuric acid, dilute hydrochloric acid and caustic alkali. Nickel cast iron is an ideal valve material. At present, nickel cast iron valves are very rare, and the article will not introduce them for the time being.