Effect of Si Content on Wear Performance of Hot Work Tool Steel

With the introduction of modern low-weight high-strength materials, tools and dies in hot metal forming are exposed to increasingly demanding contact conditions. This requires use of surface engineering techniques and proper balance between core hardness and fracture toughness. However, it is not very straight forward which combination to use in terms of wear resistance. The aim of this work was to investigate the effect of Si content on properties of AISI H11-type hot work tool steel in relation to austenitizing and tempering temperature. Work was focused on the core fracture toughness and fracture toughness versus hardness ratio and how they affect galling and wear resistance of plasma nitrided hot work tool steel. In the case of high Si content, increased austenitizing temperature results in high core hardness but considerable drop in fracture toughness and wear resistance. However, for low Si content, increased core hardness is accompanied with improved fracture toughness and greatly improved wear resistance. Galling resistance on the other hand is more or less independent of the substrate properties and mainly depends on surface conditions and plasma nitriding process.