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.
