Because fluoroplastics have unique performance advantages in resisting strong corrosive media, they are lined on the inner wall of various cast iron, cast steel, carbon steel and stainless steel valve bodies or pipe fittings and the outer surface of valve internals. They are suitable for strong corrosive media under different conditions, and can replace expensive rare metals. They are the preferred products for devices in petroleum, chemical, pharmaceutical, smelting, food and chemical industries.