Steel flange is a flange made of iron and Carbon, Silicon, Manganese, Phosphorus, Sulfur, together with a small number of other elements. Steel flange can be divided into low carbon steel flange, medium carbon steel flange, high carbon steel flange and alloy steel flange. Steel flange has solid structure, small volume, tight and reliable, easy operation and maintenance, pressure resistance, corrosion resistance, excellent sealing performance and wide range of use. Steel flanges are widely used in Petroleum, Chemical, Food, Dairy, Pharmaceutical, Machinery, Manufacturing, Sewage treatment, Municipal water supply pipes and other industries.