On positive experience in application of ferroalloys under microarc thermochemical treatment

Abstract

The aim of the research is to study the possibility of the accelerated formation of a highly-rigid carbide coating on the surface of steel products. The use of the microarc thermochemical treatment technology is proposed. A steel article is placed into the black coal powder and is heated by transmission of the electric current. The formation of the microarc discharges in the powder environment leads to the carbon saturation of a surface, and the simultaneous diffusion in metal allows forming a highly rigid carbide layer. The possibility of ferroalloys usage as a source of the carbide forming metal under the formation of a highly rigid coating with the help of the microarc chemical heat treatment is established. The electrical conductivity of ferroalloys is higher than chemical combinations, and it allows obtaining acceleration of diffusion saturation due to the intensive formation of the fissile atoms of metals under the influence of microarcs. The application of ferroalloys is more favorable in terms of power, as restitution of metal oxides to an atomic state requires additional energy cost. When using ferrochrome, ferromolybdenum and ferrotungsten, a surface carbide layer up to 160 microns thick and with microhardness to 18 hPa is formed.