The Effect of High-Temperature Solution Treatment on the Toughness of 10Ni High-Toughness Ultra-High Strength Steel

Abstract

It has been found out in low-carbon 9 to 10 Ni high-toughness ultra-high strength steels that high-temperature solution treatment above 1200°C improves their toughness (vE shelf) significantly. This corresponds to the solution of coarse M₆C carbides greater than 0.3μ, which are retained in the steels at the state as rolled or as ordinarily heat-treated. These carbides again precipitate between 900 to 1100°C during cooling after high-temperature solution treatment at the cooling rate slower than 0.5°C/s. The steels high-temperature solution-treated exhibit excellent vEshelf without deterioration of proof strength and ductile-to-brittle transition temperature, compared to conventional heat treatment, when they were again austenitized at lower temperature before aging.