| 摘要 |
PURPOSE:To obtain steel powder of low C contg. more easily oxidizable elements than Fe such as Cr, Mn, etc., by treating the steel powder which is relatively low in O and high in C and contains said elements in the wet H2 atmosphere with H2O of adequate partial pressure ratios. CONSTITUTION:Steel powder contg. >=0.1wt% C, and <=0.2wt% O and >=1 kind among Cr, Mn, V, Nb, B, Si is treated under conditions of 750<=(t)<=1,250, <=0.04 PH2O/PH2 (PH2O: partial pressure of steam, PH2: partial pressure of hydrogen) in an atmosphere consisting at least of H2O and H2 at t deg.C. The steel powder is accelerated of decarburization in the wet H2 atmosphere and the oxidation of Fe and the above-described easily oxidizable elements by steam is obviated, thus the steel powder is decarburized efficiently. Here, <=0.04 PH2O/PH2 is preferable with <=0.1% C and <=0.2% O which are considered to give no adverse influence upon the compressibility, moldability and sinterability of the steel powder. As the (t) is higher, the decarburization effect is better but oxidation is accelerated and therefore the above-described range is preferable. |
