25Cr-20Ni 耐熱鋳鋼におけるσ相の同定

概要

論文の詳細を見る
Some experiments were carried out by means of X-ray diffraction, electrolytic isolation and potentiostatic etching technique, in order to make clear the relation between precipitated carbides and σ-phase in 25Cr-20Ni heat-resistant cast steel. The results obtained were summarized as follows : (1) When electrolytic residues contain more than 5 wt% of σ-phase, it can be identified by X-ray diffraction method. (2) For the electrolytic isolation of σ-phase, 45 wt% FeCl_3 aq. solution showed a favourable result as compared with 10 vol% HCl-C_2H_5OH solution. (3) Not only M_7C_3 is distinguishable from M_<23>C_6 carbide but also σ-phase from M_<23>C_6 by means of potentiostatic etching in 10 n-NaOH solution. At 200 mV vs. Hg-HgO reference electrode M_<23>C_6 carbide is etched more rapidly than M_7C_3 carbide or σ-phase, at 500 mV M_<23>C_6 and M_7C_3 carbides, or M_<23>C_6 and σ-phase are simultaneously etched, and at 600 mV, σ-phase etched most rapidly. (4) From these investigations it was found that σ-phase may be possible to precipitate even in the prolonged heat treated cast steel containing 0.35% carbon.
社団法人日本鉄鋼協会の論文
1968-05-01