Effect of Grain Size of Tungsten Carbide in the Anode Material VK8 on the Formation of Alloyed Steel Layer 35

Abstract

The influence of the grain size of tungsten carbide in tungsten-cobalt hard alloy, received as anode material for the electro-spark deposition (ESD) of steel 35, on its erosion resistance, on the weight gain of the substrate material, and on the coefficient of electro-mass transfer is studied. It is shown that a pressing charge with additives of 0.4% Cr₃C₂–0.4% VC grain growth inhibitors and grinding in alcohol and argon atmosphere at a grinding time of 20 to 320 min was used in the preparation of new anode materials with different structure, density, porosity, fracture strength, and grain size of tungsten carbide. The results of the erosion resistance and the use of the obtained new anode materials in the ESD of steel 35 are shown. When performing kinetic studies, a number of indicators of the efficiency of the formation of the doped layer were identified taking into account the obtained values of the of additional weight of the cathode, the time of the ESD, the specific surface area of 1 cm², and the coefficient of electro-mass transfer at the ESD of the studied anode materials. The results of the studies of the structure, thickness, composition of the doped layer, and of the heat resistance and wear resistance of the coating are shown. It was revealed that, among the created new anode materials, the best oxidation resistance of the coating after ESD with the selected processing modes were obtained using a new nanodispersed anode material WC8%Co–0.4%Cr₃C₂–0.4%VC, with an average grain size of 0.8 microns WC.