Carbon nitrogen penetration belongs to the surface treatment of chain. We know that carburizing is to increase the surface hardness of the chain. Then nitrogen seepage treatment is to increase the fatigue strength and corrosion resistance of the chain. Carbon nitrogen penetration is the surface of two elements of carbon and nitrogen into the chain surface. This processing can make the chain have two types of processing. The price of the same process is also higher. Users can choose suitable surface treatment in combination with their actual use.