Alloy steel is a type of steel in which some elements in steel (such as chromium, manganese, molybdenum, nickel, etc.) are incorporated to improve the performance and service life of the steel. According to the different types and contents of alloy elements, alloy steel can be divided into many different types, such as low alloy steel, high alloy steel, special steel, etc. Among them, stainless steel, which mainly incorporates elements such as chromium and nickel, is an important type of alloy steel.