부산대학교 도서관

The hydrogen embrittlement (HE) characteristics of Fe–0.33C–1.2Mn–xNb–xMo steels were investigated experimentally using various samples with differing microstructural characteristics. HE in steels was affected by hydrogen trapping sites: ε-carbide-based, Nb-based, and Mo-based precipitates, which were effective at enhancing HE resistance. In contrast, the prior austenite (γ) grain boundary within steel could act as hydrogen trapping sites and accelerate HE. In addition, hydrogen trapping occurred around the crack, leading to an acceleration of crack growth rate. There are various trapping sites in the steels with negative and positive effects on HE. The extent of the HE was clarified via tensile strength and resistance of delayed failure. Furthermore, the HE characteristics were analyzed using the samples with different quantity of hydrogen charged with two different methods. Based upon the above work, high HE resistance of the steel was proposed as Fe–0.33C–1.2Mn–0.05Nb–0.5Mo steels after a bake-hardening process at 170 °C for 20 min. [ABSTRACT FROM AUTHOR]