Effect of Deep Cryogenic Treatment Duration on the Microstructure and Wear Resistance of Hot‐Work Die Steel

This study investigated the effect of deep cryogenic treatment (DCT) duration on the microstructure, hardness, and wear resistance of two experimental H13 hot‐work die steels with different chemical compositions. The steels were quenched, subjected to DCT at –196 °C for 10, 20, and 30 h, and subsequently double tempered. The microstructure was characterized by EBSD, SEM, XRD, and EDS, while the hardness and wear behavior were evaluated by Vickers hardness and dry sliding wear tests. With increasing DCT duration, Steel B exhibited a pronounced microstructural response, resulting in a decrease in retained austenite from 13.7% to 3.5%, an increase in hardness from 310.3 to 343.1 HV, and a reduction in wear loss from 12.9 to 5.7 mg. In contrast, Steel A showed only slight changes in microstructure, hardness, and wear behavior. These results demonstrate that the response of hot‐work die steels to DCT is governed by the combined effects of chemical composition and initial microstructure, providing guidance for optimizing cryogenic treatment to improve wear resistance.