Surfacing of stamping tools with subsequent nitrocarburizing for their effective restoration

Abstract

The possibility of restoration and hardening of stamping tools by surfacing them with special electrodes OZSh-1 and TsN-4 with subsequent nitrocarburizing is shown. The microstructure of nitrocarburized surfacings on transverse sections was studied using a Quanta 650 FEG microscope by scanning electron microscopy. The dependence of the abrasive wear of the deposited coatings on the carbonitriding temperature has been experimentally established. It has been established that the increased wear resistance of nitrocarburized surfacings is due to the characteristics of the carbonitride structure of the diffusion layers, which depend on the alloying of the deposited metal and on the nitrocarburizing modes. The features of chemical-thermal treatment in a highly active nitrogen-carbon paste, which leads to the formation of diffusion layers with excess carbonitrides having high hardness on the surface of the deposited metal, are considered. The high efficiency of a pasty coating based on amorphous carbon and nitrogencontaining components (urea and potassium ferricyanide) has been experimentally shown. It has been established that for the restoration of small die tools with small allowable wear, it is advisable to use chromium-molybdenum surfacing with an OZSh-1 electrode, nitrocarburized at a temperature of 700 °C, for large-sized dies, manganese surfacing TsN-4. At the same time, carbonitriding of manganese coatings deposited with TsN-4 electrodes must be carried out at a temperature of 900 °C in order to obtain carbonitride layers of great depth on the surface of the restored stamps.