Кафедра матеріалознавства та прикладної механіки (МПМ)

The article is devoted to the improvement of heat treatment regimes of steel 150H15N5VM type to ensure the necessary operational characteristics of the tool. The wear resistance of the alloys during abrasive wear was studied by the method of friction against a fixed abrasive. Formation of different structural states was performed by annealing of cast steel at temperatures of 550–900 °C, as well as quenching from temperatures of 950–1100 °C, followed by tempering in the range of 550–850 °C. The structure of the steel was studied by optical metallography and the morphology of the wear surfaces – by scanning electron microscopy. As a result of research, it was established that high-chromium steel with nickel addition in the cast state has increased stability of retained austenite. To obtain maximum hardness, cast steel should be heated in the temperature range of 740 ... 790 °C for 2 ... 4 hours. As a result of annealing and following quenching with tempering, two variants of the structural state with increased wear resistance are formed – martensite and retained austenite immediately after tempering and the products of tempering of martensite and decay of retained austenite at high tempering. Wear resistance increases with increasing of quenching temperature. The main mechanism of wear is microcutting of the surface by hard abrasive particles. The drop in wear resistance at tempering temperatures of 550–650 °C is a consequence of a decrease in hardness and is accompanied by changes in the micromechanism of the wear surface destruction – the appearance of local centers of destruction. A significant increase in wear resistance with a further increase in tempering temperature, especially at small specific loads, can be explained by the formation of special carbides of alloying elements in the matrix.

Кафедра матеріалознавства та прикладної механіки (МПМ)

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