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Strong quenching process compared with conventional processes , with energy efficient, environmentally friendly, low cost , is a promising new treatment technologies are being widespread international attention. Based on the case-hardened steel 18Cr2Ni4WA strong steel and hardened steel 20CrMnTi processed, analyzed by a special process treated microstructure and mechanical properties , combined with the organization , performance, the relationship between technology gives optimum treatment process . Experimental results show that in the text of the selected steel grades and sample size conditions, at different concentrations CaCl 2 solution , liquid nitrogen , and different concentrations CaCl 2 solution plus nitrogen conditions strong quenching , can appear fine organizations, and materials with high strength and good toughness. Results suggest strongly quenched microstructure is mainly residual austenite lath martensite , the sample present on the surface residual compressive stress , the residual compressive stress in between 75-310MPa . Compared with the conventional heat treatment , quenching the carbon steel strong tensile strength, impact toughness and other mechanical properties increased by 10 % -30 % , reaching carburizing steel performance requirements. Analysis shows that the surface is strongly quenched the presence of residual compressive stress of low-carbon steel has a higher fatigue resistance .
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