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Abstract:
The article describes a new method of forming the protective coatings of steel parts operating under conditions of abrasive wear both in general mechanical engineering, the composition of which is of 90% ВК6 + 10% 1М, and in industries, where there may be radiation exposure and the composition of 1М (70% Ni, 20% Cr, 5% Si, 5% B), by applying them by the method of electrospark alloying (ESA) with compact electrodes-tools made of nichrome wire X20Н80 and ВК6 hard alloy and using special technological media (STM), which include the necessary alloying elements. As a result of these research, it is established that the surface layers of the 45 and Р6M5 steels after applying wear-resistant coatings have a structure that consists of three areas: the ‘white layer’, the transition zone below, and the base metal. When the discharge energy (Wp) increases from 0.52 to 2.6 J, the thicknesses of the ‘white layer’ and the transition zone, their microhardness and surface roughness increase, but the integrity of the applied coating decreases. The highest microhardness of 9750-12800 and 14250-14600 MPa corresponds to the coating formed on steel 45 and Р6M5, respectively, during ESA by means of both the compact electrodes-tools made of hard alloy ВК6 and the STM with the composition of 0.5% Si + 0.5% B + 2% Cr + 7% Ni + 90% Vaseline.

Keywords:
electrospark alloying, electrode tool, coating, white layer, microhardness, roughness, continuity