The microstructure of Monel 400 alloy is a high strength single-phase solid solution, it is a kind of corrosion-resistant alloy with maximum dosage, widest use and excellent comprehensive performance. The alloy has excellent corrosion resistance in hydrofluoric acid and fluorine gas medium, and has excellent corrosion resistance to hot concentrated lye. At the same time also resistant to neutral solutions, water, seawater, atmosphere, organic compounds and other corrosion. An important characteristic of the alloy is that it does not produce the stress corrosion crack generally, and the cutting performance is good. The alloy is mainly used for stem, pump shaft and impeller, conveyor scraper, oil well drilling ring, elastic parts, valve pad and so on.