Research on hydrogen permeation in the X80 steel heat-affected zone with different heat inputs

Abstract

Through electrochemical hydrogen permeation experiment at different hydrogen charging current densities, the hydrogen diffusion kinetic parameters such as penetration time tB , steady-state hydrogen permeation current density I ∞, hydrogen diffusion coefficient D, adsorbed hydrogen concentration C 0, hydrogen flux J, and hydrogen trap density NT in the heat-affected zone of X80 steel welding with different heat input were analyzed. The results show that the penetration time gradually decreases, and the I ∞ gradually increases with the increase of hydrogen charging current density. The penetration time of BM at the same hydrogen charging current density is the smallest, and the penetration times of CGHAZ specimens with different heat input conditions are relatively close. BM has the most significant hydrogen diffusion coefficient and negligible hydrogen trap density at the same hydrogen charging current densities. For CGHAZ, D significantly decreases and NT substantially increases, and there exists a threshold value that makes the lowest D in the CGHAZ with different heat inputs.