| For the purpose of investigating the mechanism of deoxidation cf stainless steel, the oxidation reaction rates of 17Cr, 18Cr-8Ni stainless steels and electrolytic iron being in the solid state were measured by means of T. G. -D. T. A. technique. And the behaviors of oxides and inclusion in the melt were studied by the X-ray methods. From this experiment, the following conclusion can be drawn. 1) With the heat-reaction curves the endothermic reactions were shown in electrclytic iron and stainless steels (AISI 430, 304 type) above 500℃ and 800℃, respectively. This is seemed to be the heat decomposition of ferric oxides to ferrous oxides accompaning with the increase in the weight rapidly. 2) Being heated from room temperature to 1100℃, electrolytic iron and 17Cr stainless steel represented parabolic-linear curves resulting in the increase in weight, and 18Cr-8Ni stainless steel was depicted parabolic curve with the increase in weight. 3) Chromium oxides, formed in the 17Cr and 18Cr-8Ni stainless steels at the heating stage, were observed as FeO·Cr₂O₃·in the slag and, on the other hand, as Cr₂O₃and Fe₃O, in the inclusions in the as cast state. And FeO, SiO₂ or MnO could not be identified by the X-ray diffraction method. |
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