抄録
In order to understand the difference between SSRT (slow strain rate test) and CSRT (conventional strain rate test) in susceptibility to hydrogen embrittlement, published TDS (thermal desorption spectroscopy) curves were studied on SCM435 steel that were quenched and tempered to 1300 MPa class tensile strength. The peak temperature of TDS curves of SSRT was higher than that of CSRT, and curves of SSRT swelled at higher temperatures than the peak. All the TDS curves were successfully decomposed using Gaussian distribution to sub peaks of lattice hydrogen, and hydrogen trapped by dislocation, grain boundary, vacancy and vacancy cluster. Certain amount of hydrogen was trapped by vacancy and vacancy cluster that were formed under elastic loading of CSRT and SSRT. Hydrogen was transferred from dislocation trap to grain boundary trap in case of SSRT. As the grain boundary fracture is prevailing in SSRT, hydrogen trapping by grain boundary was judged to be more important for understanding hydrogen embrittlement of high strength martensitic steels than formation of vacancy and vacancy cluster.
