Alloy steel refers to steel with high strength and good chemical stability at high temperature. It includes two types of anti oxidation steel (or high temperature resistant steel) and hot steel. Anti oxidation steel generally requires good chemical stability, but the capability is limited. High temperature strength and the corresponding oxidation resistance of heat and strong steel are required. Heat-resistance steel is often used in the manufacture of boiler, steam turbine, power machinery, industrial furnace and aviation, petrochemical and other industrial sectors in the work of the high temperature parts. In addition to the requirements of high temperature strength and high temperature oxidation corrosion, sufficient toughness, good shaping and welding are also required according to the different use, as well as a certain organizational stability. In addition, some new low chromium nickel oxidation are also developed .