電解分離による軸受鋼の炭化物の挙動について

概要

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The carbides of the ball bearing steels are isolated electrolytically and their nature is investigated. The results are as follows. (1) Electrolytic isolation of the carbide of the annealed ball-bearing steels is more effectively performed (its efficiency is about 92%). But in case of the hardened steels its efficiency falls to about 70∿80%. In some material the matrix undissolves partly and contaminates the residue of the carbides. (2) The annealed ball-bearing steels contain the carbide about 15%. Cr, Mn, and V are contained more in the carbide and Ni in the matrix, and particularly Cr is conspicuous. In SKF steels Cr content of cementite is 9.23%, and in home-made steels 8.79%. The carbide contains 98% (SKF) and 93% (H. M) of the total Cr. (3) When the bearing steels are heated above A_1, the chemical composition of the non-dissolved cementite changes as follows. Cr increases with the temperature, V also a little, Mn decreases first and increases somewhat afterwards. (4) The ball-bearing steels are usually hardened at 820∿840℃, at this state the non-dissolved cementite content is 8∿9% in SKF steels and 7∿8% in home-made steels. The chemical compositions of the matrix are 0.5% C, 0.5∿0.6% Cr and 0.2% Mn in SKF steels and 0.5%C, 0.6∿0.7% Cr and 0.3% Mn in home-made steels.
社団法人日本鉄鋼協会の論文
1957-08-01