201 stainless steel pipe

201 stainless steel is a 200 series austenitic stainless steel developed by replacing nickel with elements such as manganese and nitrogen.

201 stainless steel has certain acid and alkali resistance, high density, no bubbles when polished, no pinholes, etc. It is a high-quality material for the production of various watch cases, watch strap bottom covers, etc. Mainly used to make decorative pipes, industrial pipes, and some shallow stretched products.

200 series stainless steel was first developed in the United States as a substitute for 300 series stainless steel during World War II. At that time, due to the war, nickel, as a strategic material, was strictly controlled by relevant countries, and the supply of nickel in the United States was seriously insufficient. In order to solve the production and supply problems of stainless steel when the supply of nickel is seriously insufficient, the United States has developed this new series of austenitic stainless steel grades using manganese instead of nickel.

After the end of World War II, the supply of nickel in the United States gradually improved. Therefore, the production of 300 series stainless steel was no longer restricted by the shortage of raw materials, so the 200 series did not receive major development. Several Indians who participated in the development of 200 series stainless steel originally brought the 200 series stainless steel varieties developed in the United States back to India after returning to India, considering that India is a country with relatively rich manganese resources and a lack of nickel resources.

The application of 200 series stainless steel has been successful in India because it is possible to replace 304 stainless steel in some specific uses.

Most of the 200 series stainless steel sold in the Chinese market barely controls the sulfur and carbon content in accordance with national standards, and replaces part or all of nickel with manganese (and nitrogen) to produce austenitic stainless steel with lower nickel content.

The disadvantage of this series of materials is that the chromium content below 18% cannot reach a balance with the low nickel content and ferrite is formed. For this reason, the chromium content in 200 series stainless steel is reduced to 13.5% to 15%, and some The situation has dropped to 13% to 14%, and its corrosion resistance cannot be compared with 304 and other similar steels. In addition, manganese and in some cases copper reduce the repassivation effect under the acidic conditions common in corrosion areas of deposits and crevices. 200 series steel destroys approximately 10-100 times faster than 304 stainless steel under these conditions. The residual sulfur and carbon content in these steels often cannot be controlled during production, and the materials cannot be traced, even during material recycling. If Cr-Mn steels are not accounted for, they become a dangerous scrap mix, resulting in castings containing unexpectedly high manganese content.