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The influence of heat treatment different options on wear resistance of steels of trademarks Kh12MFL and 150KhNML applied in manufacturing of mud pumps is reviewed. It is shown that the steel Kh12MFL is superior in wear resistance than the steel 150KhNML at abrasion. The martensite-carbide structure of both steels obtained at quenching at normal temperatures, from 900 to 1000 0С, ensures a good hardness (61-64 HRC). The analysis of the residual austenite contents influence on wear resistance was also made. It was determined that residual austenite formed after high temperature quenching (110-1170 0С) was metastable and had a tendency to transform into carbon containing martensite of deformation in the process abrasive wearing. This allowed steels to have a maximum wear resistance because of ensuring a high ability to frictional hardening of the working surface.

The paper shows that high temperature heating (from 1 100 to 1 170 0C) for the subsequent quenching of high-chromium steels of a martensitic-carbide class 95X18 and X12MFL provides structure to the metal base, which consist of high-carbon containing martensite and residual metastable austenite with some carbides. The resulting structure has a high capacity for frictional hardening. Experiments with cold processing treatment of the analyzed steels also showed that after high-temperature quenching with subsequent cooling to -70 0C, sufficient cooling martensite is formed, which in combination with residual metastable austenite, provides an increase of abrasive wear resistance by 25 % compared to high temperature annealing.

The paper studies the effect of quenching in a wide range of temperatures on the quantity of metastable residual austenite, its stability, hardening and wear resistance in the process of abrasive wear of high-carbon tool steels of the pearlitic and ledeburitic classes -150KhNML and Kh12MFL. Despite decreasing initial hardness with increasing quenching temperature, the abrasive wear resistance of the steels increases, this being due to a change in the quantity, composition and deformation stability of residual austenite. The increase in the relative wear resistance of both steels with increasing quenching temperature correlates with hardenability determined by measuring the microhardness of the gauge surface after wear. The cold treatment of the Kh12MFL steel after hightemperature quenching additionally enhances its abrasive wear resistance by 25 % due to the formation of 15 % of high-carbon-chromium cryogenic martensite and increases the initial hardness to 60 НRC with the preservation of 20 % of residual metastable austenite and carbides. Shabashov V.A., Korshunov L.G., Mukoseev A.G., Sagaradze V.V., Makarov A.V., Pilyugin V.P., Novikov S.I., Vildanova N.F. Deformation-induced phase transitions in a highcarbon steel. Materials Science and Engineering: A, 2003, vol. 246, pp.196-207. DOI: 10.1016/S0921-5093(02)00549-X. 2.Filippov M.A., Gervasiev M.A., Khudorozhkova Yu.V., Legchilo V.V. Effect of quenching temperature on the phase composition, structure and wear resistance of the 150KhNM steel. Izvestiya vysshykh uchebnykh zavedeniy.