Ni含有低合金鋼の大気中における高温酸化挙動

抄録

The oxidation behavior of low-alloy steels with Ni of 0-4.8% has been investigated in the temperature range of 1173-1573K in the Air. The results obtained are summarized as follows.
Scale properties changed remarkably whether the steel contained Ni or not. On the Ni bearing steels, subscales consisting of oxide and Ni enriched metal grew even if the steel contained less than 1.0% Ni.
Total oxidation rate and external scale thickness decreased in the case of Ni bearing steels, but the dependence of the Ni content was small. On the other hand, the subscale thickness increased with an increase in the Ni content. At all temperatures, total oxidation, external scale and the subscale thickness grew according to the parabolic rate law.
At 1573K, the external scale thickness of Ni bearing steels decreased compared with the thickness at 1373K. The subscale thickness, however, increased with the rise in the temperature, and particles of oxide and metal in subscale became coarse. This was because the supply of Fe²⁺ for the external scale was retarded and the diffusion of Fe²⁺ in subscale oxide was promoted, according to the formation of liquid Fe₂SiO₄.