1. A study was made of the wear of VK and TK type sintered hard alloys during the electromachining of Armco iron and steel 3, 45, U8, and ShKh15 steels. 2. It was established that, generally speaking, the highest wear resistance is exhibited by the VK group of hard alloys, whose wear is essentially due to adhesion. It is postulated that TK group hard alloys wear out as a result of interdiffusion between the tool electrode material and the steels being machined. 3. The relationship was examined between tool electrode wear and the ratios of the elastic moduli and thermal conductivities of the tool and workpiece materials. It was established that, as the ratios of these characteristics increase, the wear of hard alloys becomes greater. 4. A study was made of the wear of tool plates as a function of the carbon content of steels. It was found that the wear surface area appreciably increases only up to a certain carbon content (0.8% C), markedly decreasing for ShKh15 steel.