Sequential kinetic analysis of the influences of non-metallic inclusions on hydrogen diffusion and trapping in high-strength pipeline steel with Al-Ti deoxidisation and Mg treatment

Abstract

The sequential kinetic behaviour of different non-metallic inclusions on hydrogen diffusion and trapping was investigated. The kinetic process can be divided into three stages including the hydrogen trapping, trapped hydrogen desorbing, and the desorbed hydrogen diffusing. The priority of the interface on trapping hydrogen descend in the following order: MnS, Al2O3, MgAl2O4 and TiN. There exists a hydrogen trapping saturated state in which hydrogen trapping and desorption reach a dynamic equilibrium. It is not the hydrogen segregation energy but the residual stress level around inclusions that is the main factor determining the kinetic behaviour of hydrogen trapping and diffusion.