Abstract
State of hydrogen in V-bearing steel was explored by peak separation with Gaussian distribution on published hydrogen desorption curves (TDS curves) for Mn-0. 3%V, Mn-1%V and Cr-Mo-0. 35%V steels. As is well known, two kinds of hydrogen traps were formed, which were corresponding to V-containing carbides in different morphology. Including the ordinary hydrogen traps, i. e. lattice, dislocation and grain boundary traps that are common to ferritic steels, the TDS curves from the above-mentioned three V-bearing steels were systematically separated into Gaussian sub-peaks. Although most hydrogen is trapped by two hydrogen traps relating to V carbide, hydrogen is still shared by dislocation and grain boundary traps. The alloying of V played a role of decreasing the of grain boundary trap. This decrease is more notable for Cr-Mo-V steel than Mn-V steel, owing to the changes in carbide structure and morphology by V alloying. Cr-Mo-V steel has another feature:The peak temperature became more elevated for weaker and lower temperature hydrogen traps, probably because of suppressed diffusion rate of lattice hydrogen in Cr-Mo based steels.
