At present, chromium and manganese series development market chaos, recommended by many international steel and research institutions to develop new 200 series direction, such as the research and development of a university than Letuoliya Cr-Mn wire rod of high strength structural performance instead of carbon steel, the yield strength of 400Mpa reached above 2% ~>, Ni content, nitrogen element, France Asaro developed by 202N and 204Cu, the corrosion resistance of more than 304 and 316 grades, the latter is equivalent to 304, far more than 430 grades.