There is no uniform definition and concept for special steels. Special steels are generally considered to have special chemical composition (alloying), special production process, special structure and properties, and special steel requirements.
Compared with ordinary steel, special steel has a higher strength and toughness, physical properties, chemical properties, biocompatibility and process performance. China and Japan, the European Union on the definition of special steel is relatively close to the special steel into high-quality carbon steel, alloy steel, high alloy steel (alloy elements greater than 10%) three categories, including alloy steel and high alloy steel production of special steel Of the total.
Alloy steel, alloy steel, alloy steel, alloy steel, alloy tool steel, high-alloy tool steel, high-speed tool steel, stainless steel, heat-resistant steel, carbon steel, carbon steel, alloy steel, , And high-temperature alloys, precision alloys, electric alloy, and so on.
At present the world has nearly 2,000 special steel grades, about 50,000 varieties of specifications. In addition to a wide range of special steel, the specifications are also shown with different characteristics of ordinary steel. In addition to plate, tube, wire, belt, bar and profile, there are composites, surface alloying materials, surface treatment materials, precision forging materials, precision castings, powder metallurgy products.