Structure, tribological and mechanical properties of high-chromium nitrogen-containing martensite-based steels

The wear resistance by the abrasive impact and sliding friction in the oxidizing and nonoxidizing media of ten nitrogen-containing (0.07-0.22 wt. % nitrogen) high-chromium steels with the martensitic, martensite-ferrite and martensite-austenite structures, as well as the mechanical properties of three martensitic nitrogen steels and carbon-containing steel 20Kh13 (0.19 % carbon) is studied. The increased resistance to wear under the conditions of the sliding friction of the martensite-ferrite steels, as well as the positive effect of the metastable nitrous residual austenite on the wear resistance and decrease in the friction coefficient of the martensite-austenite steel are identified. The additional alloying of the nitrous steels with the molybdenum and vanadium does not lead to increase in their abrasive wear resistance. Strong negative effect of the friction oxidation on the wear resistance of the nitrogen-containing steels by the friction in the air is identified. Relative to the wear resistance in the nonoxidizing medium (the nitrogen-containing martensite steels are comparable with the 20Kh13 steel. The less effective nitrogen effect (in comparison with the carbon) on the strength properties of the steels with the martensitic structure is identified. The increase brittleness of the nitrogen-containing martensitic steels under the conditions of mechanical and tribological tests is established