THE STUDY OF THE FORMATION OF THE DOPED LAYER AND OF THE PROPERTIES OF ELECTRO-SPARK ALLOYING OF STEELS 35 AND KH12F1 SOLID AND MODIFIED ALLOYS
The results of a comparative study of the formation of a protective layer and its properties by the method of electrospark doping (ESA) using carbon steel 35 and chromium tool steel KH12F1 as the substrate using tungsten-containing anodic materials containing solid alloys, industrial based on WC-Co8% and nickel-produced chrome hard alloy with self-fluxing additives WC-Co8%-(Ni-Cr-B-Si) 20%. The results of the kinetic processes of anode erosion and mass transfer at the cathode with the mechanized ESA of the 35 and KH12F1 steels studied by the anode materials are shown. The greatest total weight gain before the brittle fracture threshold appears when ESA of both steels is modified by the modified WC-Co8%-(Ni-Cr-B-Si)20% alloy. The results of the particle size distribution of the products of erosion are demonstrated, which show the dependence on the chemical and phase compositions, the physicochemical properties of the anode material, its structure, and the processing mode. The ratios of the liquid and solid phases of the products of erosion, as well as their particle size distribution with mechanized ESA of steels 35 and KH12F1, are given. Comparative tests for wear resistance after electric-spark doping, which were carried out under conditions of friction without lubrication according to the «shaft-block» scheme, were carried out. The results of the study of the wear resistance of surfaces showed a significant increase in comparison with surfaces without electrospark alloying, with the best values of wear resistance obtained using KH12F1 steel and the anodic material obtained. It was established that the modification of the VK8 hard alloy by introducing a self-fluxing component (Ni-Cr-B-Si) allows to increase the kinetic indicators of the formation of the doped layer during ESA, its wear resistance. According to the results of comparative tests of electrospark alloying of steels by the anodic materials under study, the values of the indicators of the efficiency of electrospark alloying are shown.