構造用強靱合金鋼中の水素拡散に及ぼす焼入れ焼戻し組織の影響
1978 年 42 巻 4 号 p. 325-330
詳細
1978 年 42 巻 4 号 p. 325-330
The effect of quenched and tempered structure on the diffusion coefficient and solubility of hydrogen in high-strength alloy steels, such as Cr, Cr-Mo, Ni-Cr and Ni-Cr-Mo steels, have been investigated at room temperature by means of electrochemical permeation technique.
The diffusion coefficient and the solubility of hydrogen vary with the structure of the steel; the former shows a minimum, when the steels are quenched and tempered at 300°C except for a case with high Mo content, while the latter exhibits a maximum at that temperature. In the case of steels having comparatively higher Ni, Cr and Mo contents, the structure of bainite plus martensite obtained by furnace cooling from the temperature above Ac1 have lower values of diffusion coefficient which are comparable with that of the as-quenched martensitic structure. The dependence of hydrogen diffusion on the quenched and tempered structure can be explained by postulating that both the lattice imperfections, such as dislocations, faults, lattice vacancies and subgrain boundaries introduced by the martensitic and/or bainitic transformation, and the interfaces between the ferrite phase and carbide precipitates, provide regions for the occupancy of hydrogen.
