抄録
Experimental thermal desorption curves of vanadium (V)-bearing high strength steel were successfully separated, by the use of Gaussian distribution function, into desorption curves for hydrogen traps of dislocation (A1) , grain boundary (A2) , two types of vanadium carbide (V1 and V2) . The amount of A2 hydrogen (hydrogen trapped by grain boundary) rationalized the strength in different types of hydrogen embrittlement tests, i. e. conventional strain rate test (CSRT) , slow strain rate test (SSRT) and constant load test (CLT) . The strength dropped steeply beyond the threshold amount of 0. 15 ppm. All the four kinds of trapped hydrogen (A1, A2, V1 and V2) were revealed in equilibrium of Fermi-Dirac statistics. Over half of total hydrogen was trapped by the two kinds of V-carbide (V1 and V2) , and the rest was partitioned into A1 and A2 hydrogen; more hydrogen was partitioned into A2 hydrogen by SSRT and CLT than by CSRT. The partitioning was hardly affected by vanadium alloying. The threshold amount of A2 hydrogen may be originated by the suppressed amount of impurity atoms and carbide along grain boundary.
