ferritic stain less steel introduction

The chromium content is 12% to 30%. It is a stainless steel with body-centered cubic lattice ferrite as the matrix structure at high and normal temperatures. This type of steel generally does not contain nickel, and some contain a small amount of elements such as molybdenum, titanium or niobium, and has good oxidation resistance, corrosion resistance and chloride corrosion resistance. Ferritic stainless steel can be divided into low chromium, medium chromium and high chromium according to the chromium content. According to the purity of steel, especially the content of carbon and nitrogen impurities, it can be divided into ordinary ferritic stainless steel and ultra-pure ferritic stainless steel. . Ordinary ferritic stainless steel has shortcomings such as low temperature and room temperature brittleness, notch sensitivity, high intergranular corrosion tendency, and poor weldability. Although this type of steel has been developed earlier, its industrial application has been greatly restricted. These shortcomings of ordinary ferritic stainless steel are related to the purity of steel, especially the high content of interstitial elements such as carbon and nitrogen in steel. As long as the carbon and nitrogen in the steel are low enough, for example, not more than 150×10～250×10-6, the above shortcomings can basically be overcome. After the 1970s, due to the development of smelting technology, especially vacuum metallurgy and secondary refining, high-purity ferritic stainless steel with carbon + nitrogen ≤ 150～250×10-6 has been produced, making this type of steel industrially available widely used.