Effects of Deep Cryogenic Treatment and Controlled Rolling on Microstructures and Mechanical Properties of an Ultra-High Strength Steel

The microstructure mechanisms and mechanical properties of 0.23C-1.96Si-1.94Cr-1.93 Mn-0.35 Mo ultra-high strength steel treated by the deep cryogenic treatment at −196 °C were investigated after was hot rolled different temperatures. Experimental results show that austenitizing zone rolling with a large reduction in single pass can comprehensively enhance due to high volume retained austenite refined lath martensite bainite. strain gradient suppressed, tensile strength, yield impact toughness, total elongation 2221 MPa, 2017 65.5 J, 16.9%, respectively. In addition, promote formation film more than dual phase rolling, decreased an increase 75%. It is demonstrated proper method toughness via refinement strengthening austenite. This work not only reveals effects gradients be markedly improved strategies, but also provides realistic preparation technology for exploitation superior applications.