The melting point ratio is high (1455 ℃), the corrosion resistance is good, and the mechanical property is high. It has some special physical properties under cold and hot conditions, and the corrosion resistance in reducing media has good corrosion resistance in concentrated alkali solution. It has excellent corrosion resistance to alkaline and neutral solution media of carbonate, nitrate, oxide and acetate salts, and is stable in strong alkali, neutral and weak acid, and in atmosphere, fresh water and sea water.