1. Nitriding ring: The hardness of the nitrided layer is above 950HV, the brittleness is grade 1, has good abrasion and corrosion resistance, higher fatigue strength, higher corrosion resistance and anti-seizure performance; piston ring deformation small.
2. Chrome-plated ring: The chrome-plated layer has fine and smooth crystals, the hardness is above 850HV, the wear resistance is very good, and the crisscross micro-crack network is conducive to storing lubricants. According to relevant information, “After the chrome plating on the side of the piston ring groove, the wear of the ring groove can be significantly reduced. On engines with moderate temperature and load, the above-mentioned methods can reduce the wear of the piston ring groove by 33 to 60”.
3. Phosphating ring: Through chemical treatment, a layer of phosphating film is produced on the surface of the piston ring, which can prevent the product from rusting and improve the initial running-in of the ring.
4. Oxidation ring: Under the condition of high temperature and strong oxidant, an oxide film is formed on the surface of the steel material, which has corrosion resistance, anti-friction lubrication and good appearance. There are also PVD and so on.
