Development of 200 series stainless steel

The 200 series stainless steel was first developed in the United States as a substitute for the 300 series of stainless steel during World War II. At that time, as a result of the war, nickel as strategic material was strictly controlled by the countries concerned, and the supply of nickel in the United States was seriously insufficient. In order to solve the problem of the shortage of nickel supply and the production and supply of stainless steel, the United States has developed a series of new austenitic stainless steel with manganese instead of nickel.
After the end of World War II, the supply of nickel in the United States has gradually improved. Therefore, the production of 300 series of stainless steel is no longer restricted by raw material, so the 200 series has not been greatly developed. Several Indians, who had been involved in the development of 200 series of stainless steel, returned to India and brought back to India the 200 series of stainless steel varieties developed in the United States, starting from the fact that India was a relatively rich manganese resource and a lack of nickel resources.
The application of the 200 series stainless steel in India has been successful because of the possibility of replacing 304 stainless steel in some specific uses.
Most of the 200 series of stainless steel sold in the Chinese market did not control sulfur and carbon content according to the national standard, replacing some or all nickel with manganese (and nitrogen) to produce austenitic stainless steel with lower nickel content.
The defects of this series of materials are that the chromium content below 18% is not balanced with the low nickel content to form ferrite. Therefore, the chromium content in the 200 series stainless steel drops to 13.5% ~ 15%, and some cases fall to 13% to 14%, and the corrosion resistance is not compared with 304 and other similar steels. In addition, under the common acidic conditions in the depositional areas and the corrosion sites of the crevice, manganese and copper in some cases reduced the effect of re passivation. The damage rate of the 200 series steel under these conditions is about 10-100 times that of 304 stainless steel. It is often impossible to control the residual sulphur content and carbon content in these steels in production. Materials can not be traced and tracked, even in material recycling. If Cr-Mn steel is not stated, they will become a dangerous scrap mixed material, resulting in unexpected high manganese content in the casting.