Investigations on Heat Treatment of a High-Speed Steel Roll

High-carbon high-speed steels (HSS) are very abrasion-resistant materials primarily due to their high hardness MC-type carbide and high hardness martensitic matrix. The effects of quenching and tempering treatment on the microstructure, mechanical properties, and abrasion resistance of centrifugal casting high-carbon HSS roll were studied. Different microstructures and mechanical properties were obtained after the quenching and tempering temperatures of HSS roll were changed. With air-cooling and sodium silicate solution cooling, when the austenitizing temperature reaches 1273 K, the metallic matrix all transforms into the martensite. Afterwards, the eutectic carbides dissolve into the metallic matrix and their continuous network distribution changes into the broken network. The second hardening temperature of high-carbon HSS roll is around 793 K. No significant changes in tensile strength and elongation percentage are observed unless the tempering temperature is beyond 753 K. The tensile strength increases obviously and the elongation percentage decreases slightly beyond 753 K. However, the tensile strength decreases and the elongation percentage increases when the tempering temperature exceeds 813 K. When the tempering temperature excels 773 K, the impact toughness has a slight decrease. Tempering at 793-813 K, high-carbon HSS roll presents excellent abrasion resistance.