Hydrogen-induced delayed fracture behaviour of V+Nb-microalloyed high-strength bolt steel with internal and environmental hydrogen. (December 2022) - Zhang, Chengxiang
Abstract: Hydrogen-induced delayed fracture (HIDF) behaviour of a V+Nb microalloyed 1300-GPa-grade high-strength bolt steel was explored by slow strain rate tensile (SSRT) tests under pre-hydrogen-charging (internal hydrogen) and dynamic hydrogen-charging (environmental hydrogen) conditions. The tested steel exhibited much lower HIDF resistance in the condition of environmental hydrogen than that of internal hydrogen, which is primarily due to the difference in hydrogen diffusion and accumulation characteristics and the hydrogen trapping effect of MC carbides. Therefore, for applications of high-strength bolt steels based primarily on the designing strategy of hydrogen trapping, it is extremely important to prevent environmental hydrogen entry in service. Highlights: Hydrogen-induced delayed fracture (HIDF) of V+Nb-added bolt steel was evaluated. HIDF was evaluated under internal and environmental hydrogen supplying ways. Environmental hydrogen degrades HIDF resistance more significant than internal one. Mechanisms for different HIDF behaviour were explored.