Alloy steel refers to steel that is made by adding some alloying elements (such as silicon, manganese, chromium, nickel, tungsten, vanadium, titanium, molybdenum, etc.) to carbon steel during smelting in order to improve certain properties of the steel. The addition of these alloying elements gives alloy steel a series of special properties that are superior to ordinary carbon steel, such as high strength, high toughness, wear resistance, corrosion resistance, low temperature resistance, high temperature resistance, etc.