Evolution of Tertiary Carbides and Its Influence on Wear Behavior, Surface Roughness and Fatigue Limit of Die Steels

摘要

The fatigue is a primary mode of failure in many hot work die steels such as AISI H13 on account of severe thermal fatigue conditions as in hot forging. The present work involves hardening of AISI H13 die steel specimens at 1020°C, oil quenching followed by double tempering at 500°C and then cryogenic treatment at minus 185°C at different cryosoaking periods from 8 to 32 h followed by soft tempering at 100°C. The influence of tertiary carbide evolution on wear behavior, surface roughness and fatigue limit was studied. It has been established that there are reduction in wear rate, improvement in hardness, surface roughness and increasing the fatigue life on account of fine tertiary carbide precipitation.