Abstract
In relation to solid-rolled wagon wheels the advantages of differentiated quenching of all wheel elements are shown in comparison with quenching of only wheel rim rolling surface. It should be noted that larger possibilities to enhance performance characteristics of heavy duty details and products can be fulfilled using the technology of overall hardening including the differentiated quenching and surface plasma processing. It is established that along with the improvement of mechanical properties plasma processing after volume quenching allows for a considerable increase of crack resistance of surveyed grades in comparison with volume quenching without plasma processing. The martensite structure of the strengthened layer during such overall processing in comparison with the martensite structure of volume and strengthened base is characterized by high level of particle size that is specified by reduction of the original austenite grain due to very high heating and cooling speeds as well as small time of steel stay at high temperatures. In order to increase hardness and resistance against cracks generation plasma processing and preliminary volume quenching are recommended. A composite working layer with high wear and crack growth resistance and relatively soft and plastic core are developed in details and products volume quenched when surface plasma strengthening.