The manufacturing of flanges is mainly divided into two types: forged flanges and cast flanges. The materials used for forging flanges can be carbon steel, stainless steel, alloy steel, etc. After forging, they are processed and the surface is generally polished, corroded, etc. Cast flanges are mainly made of materials such as cast iron, brass, and copper nickel alloy, but their strength and reliability are not as high as forged flanges.