Cap nut is a hexagonal nut with a cover, which is mainly used to prevent moisture and other corrosive substances from entering, thereby increasing the service life of the cap nut and the connecting parts. Common cap nuts include DIN1587, DIN917, DIN986, GB923, etc., usually made of carbon steel, alloy steel, stainless steel and non-ferrous metals. This nut is widely used in many fields such as machinery and equipment, automobile industry, construction industry and furniture manufacturing.