The 200 series stainless steel was first developed in the United States during World War II as a substitute for the 300 series stainless steel.
At that time, because of the war, nickel as a strategic material was strictly controlled by the countries concerned, and the supply of nickel in the United States was seriously short.
In the stainless steel industry, 201 represents a material. 201 stainless steel generally refers to the general term for 201 stainless steel and acid-resistant steel. 201 stainless steel refers to steel that is resistant to corrosion by weak media such as atmosphere, steam and water, while acid-resistant steel refers to steel that is resistant to corrosion by chemically corrosive media such as acid, alkali, and salt.
201 stainless steel mainly includes martensite, ferrite, austenite, α+γ dual phase and precipitation hardening type. The variety is complete and has continued to this day. Among them, in the 1940s and 1950s, there were Cr-Mn-N and Cr-Mn-Ni-N201 stainless steels with excessive nickel, and ultra-low carbon (C≤0.03%) austenitic 201 stainless steels. In the 1960s, γ: α+γ duplex 201 stainless steel with α close to 1 and high-purity ferritic 201 stainless steel and maraging 201 stainless steel with C+N≤150ppm are also available. Although it should be regarded as a major breakthrough in the field of 201 stainless steel, these new steel grades In essence, it still belongs to the five types of 201 stainless steel mentioned above.
In the global production of 201 stainless steel, Cr13 type martensitic steel and Cr17 type ferritic steel account for about 30%-40%, while 18-8 type chromium-nickel austenitic steel accounts for about 60%-70%. The production of 201 stainless steel in the world's industrially advanced countries generally accounts for 2.5%-3.5% of the total domestic steel. In the production process of 201 stainless steel, ultra-high power electric furnace, out-of-furnace refining, continuous ingot casting (including thin slab continuous casting), hot continuous rolling or new furnace coil rolling mill, cold continuous rolling, continuous pickling heat treatment and continuous protective atmosphere bright Stainless steel processing techniques such as heat treatment and various quality testing methods have been widely used. At present, large-scale, continuous, high-speed and automation are the main development directions of 201 stainless steel production and processing technology and equipment.
The 201 stainless steel products that can be mass-produced and supplied mainly include cold-rolled sheets with a width of up to 2m, including mirror panels, color sheets, checkered sheets, coated sheets, etc.; hot-rolled medium sheets with a width of more than 3m; Thick rolled plates; seamless pipes with diameters as large as 1m or more and as small as 0.1mm, and welded pipes of various specifications (maximum diameter up to 2m); 201 stainless steel foils with a thickness of about 0.05mm and a width of up to 1m.