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.
This new series of austenitic stainless steels with manganese instead of nickel was developed in the United States in order to solve the problem of production and supply of stainless steel under the condition of severe nickel shortage.
After the end of World War II, the supply of nickel in the United States gradually improved, so the production of 300 series stainless steel is no longer restricted by raw material constraints, so the 200 series did not get a big development.
Several original participation in the development of 200 series of stainless steel Indians, after returning to India, from India is a relatively rich in manganese resources, nickel resources lack of national conditions, will be developed in the United States 200 series of stainless steel varieties back to India.
The success of the 200 series stainless steel in India is due to the possibility of replacing 304 stainless steel in some specific applications.
Most of the 200 series stainless steels sold in the Chinese market have little control on sulfur and carbon content according to national standards, and use manganese (and nitrogen) to replace part or all of nickel to produce austenitic stainless steels with lower nickel content.
The disadvantage of this series of materials is: below 18% chromium content and low nickel content can not reach balance and form ferrite, for this reason, 200 series of stainless steel chromium content to 13.5% ~ 15%, in some cases down to 13% ~ 14%, its corrosion resistance is not compared with 304 and other similar steels.
In addition, manganese and, in some cases, copper reduce the effect of re-passivation under acidic conditions common in the corrosion sites of deposits and crevasses.
The destruction rate of 200 series steels under these conditions is approximately 10-100 times that of 304 stainless steels.
The residual sulfur and carbon content of these steels is often not controlled during production, and the material cannot be traced to its source, even when it is recycled.
If Cr-Mn steels are not specified, they can become a dangerous scrap mix, resulting in castings containing unexpectedly high levels of manganese.