For rings operating in conditions of limited lubrication, Technolit UChNPP has mastered the technology of hardening the surface layer with nitrogen in a low-temperature plasma environment, which makes it possible to obtain a hardened layer on the product surface with a hardness of up to 650 HRV to a depth of 250 … 300 microns. Ion-plasma nitriding (IPA) is a modern hardening method of chemical-thermal treatment of articles made of cast iron, carbon, alloy and tool steels. This method of hardening the working surface retains the main advantage of cast iron as an antifriction material – it leaves open the holes of graphite, which is a natural lubricant, and provides softer working conditions. Process technology Installations for IPA operate in a rarefied atmosphere at a pressure of 0.5-10 mbar. An ionized gas mixture is fed into the chamber, which operates on the principle of a cathode-anode system. A glowing pulse discharge is formed between the workpiece being processed and the walls of the vacuum chamber. The active medium created under its influence, consisting of charged ions, atoms and molecules, forms a nitrided layer on the surface of the product. The composition of the saturating medium, the temperature and duration of the process affect the depth of penetration of nitrides, which cause a significant increase in the hardness of the surface layer of products.