抄録
(1) The electrolytic extraction with 5% Na-citrate and 10% NaCl electrolyte and the subsequent treatment for purification were elaborately studied and was established the procedure for the completecollection of large inclusions (over ca.10μ) from the steel specimen.
(2) New methods were established for classifying the extracted inclusions by size, determining the composition of a particle of inclusions and observing the inner structure of inclusions and others.
(3) By utilizing this new method, the distributions of inclusions in the ingot and slab, as well as their size and composition were determined for rimmed, capped and killed steels.
