W 高速度鋼中の炭化物について : 実用特殊鋼中の炭化物の電解分離による研究 VII

概要

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The carbides isolated electrolytically from two kinds of high speed steels-18-4-1 and 11-4-2-were studied by chemical analysis and X-ray examination. The results obtained are as follows. (1) The carbides in the annealed structure of these high speed steels are composed of M_6C, M_<23>C_6 and a little amount of MC, as reported by many investigators. (2) By austenitizing treatment, M_<23>C_6 completely dissolves into matrix, but most part of M_6C remains as undissolved carbides. By the same treatment, MC in 18-4-1 steel is dissolved completely, but in the case of 11-4-2 steel, a part of it remains. (3) The chemical composition of the matrix of these steels quenched from 1250℃ are very similar as follows : 18-4-1 ; 0.5%C, 7.4%W, 4.5%Cr, 0.9%V 11-4-2 ; 0.6%C, 6.5%W, 4.7%Cr, 1.3%V (4) On tempering above 400℃, cementite appears first, and then W_2C, MC and M_7C_3 transitionally precipitate, and finaly M_6C and M_<23>C_6 are formed. (5) The tungsten concentration in precipitated carbides increases gradually with the rise of tempering temperature. But the vanadium concentration in precipitated carbides reaches to a maximum percentage, and then dicreases with the rise of tempering temperature. This may result from the fact that the rate of carbide formation of tungsten is slower than that of vanadium, and so the previously formed vanadium carbides are diluted by the later formed tungsten carbides.
社団法人日本鉄鋼協会の論文
1959-04-01