Ensuring the High Strength Characteristics of the Surface Layers of Steel Products

Abstract

New technology of nitriding of steel products allows increasing the strength characteristics of the surface layers without reducing the bulk strength of the material. Tool alloyed steels 3Cr3Mo3V, 5CrNiMo, 9CrSi and W6Mo5Cr4V2 were studied, which allowed us to evaluate the effect of alloying elements on the micro-fragility and wear resistance of hardened alloys during nitriding in a powder mixture. Nitriding of the samples was carried out at a temperature of 550 °C for 5 h in a sealed container with a dispersed powder mixture. It is shown that the formation of the diffusion layer does not affect the overall dimensions of the products. It was found that nitriding in a dispersed powder mixture provides a low micro-fineness of the surface layer of steel, which can significantly improve the reliability and durability of products. It is proved experimentally that chemical-thermal hardening allows for an increase in wear resistance of steels twice. Mathematical models of wear resistance of the investigated steels after the proposed hardening technology are obtained.