Microstructure and tensile properties of 45WCrV7 tool steel after deep cryogenic treatment

Two groups of tool steel properties, high hardness or strength, and high toughness, are important in performance of tool steels. Normally, any increase in hardness or strength occurs at the expense of reduced toughness. However, deep cryogenic treatment may be used to produce advanced tool steel by means of increasing toughness, strength and hardness simultaneously. Twelve sets of specimens were tested; nine of them were deep cryogenic treated and then tempered and 11 underwent double deep cryogenic treatment at the same temperatures. The best results as simultaneous improvement in toughness, hardness and strength were obtained for two sets.