<研究>種々の瓦斯圍氣中に於て凝固する鎔鋼の気泡巣發生に就て

概要

論文の詳細を見る
The influences of several gas atmospheres (vacuum, H_2,N_2,CO, CO_2,air and water vapour) upon the formation of blowholes in several ferrous alloys (pure iron, several binary ferrous alloys, Swedish steel, Cr-Mo steel and Si-Mn-Cr-steel) were studied. The experimental procedures were as follows : (1) 400 grams of specimen was outgassed by melting in vacuum. (2) It was remelted in each gas-stream above mentioned at 1600℃ for 30 minutes. (3) And then it was cooled in the crucible at a constant cooling rate. (4) The aspect of the section of the resulted ingot was observed with particular reference to the distribution of blowholes and dendrites. The photographs of macroetched sections of specimens were taken and they were compared with the melting processes. The sketches of typical photographs of macroetched sections were shown in Fig. 3. In some cases, the volume of gas evolved and the gas evolving process during solidification were measured. The results are briefly shown in tables, in which the notation ● corresponds to sketches A and B, 〓 to C, ○ to D and E in Fig. 3. The brief conclusions are as follows : (1) The time necessary for outgassing differs considerably in each specimen. For instance, the outgassing of electrolytic iron is easy and that of Swedish steel difficult. (2) Many large blowholes appear by H_2 evolution in all kinds of specimens tested, that is, there is no killing agents for H_2 gas. (3) The velocities of absorption and evolution of N_2 in pure iron are slow even in molten state, but these become faster by the addition of C, Si, Mn, and Cr. Hence, in alloyed irons, absorbed N_2 is evolved considerably during solidification and blowholes appear independently of cooling velocities. On the contrary, in pure iron, the cooling velocity affects the volume of gas evolved during solidification considerably as shown in Fig. 7,therefore, it also affects the appearance of blowholes. In alloys, such as high C-steels and Fe-Ni alloys, in which the melts directly solidify to γ-phase, the volume of gas evolved during solidification diminishes owing to the high solubility of N_2 in γ-phase, and at the limit there is no gas evolution. Therefore, in these cases the appearance of blowholes decreases. (4) Fc-C-O ternary melt is produced when iron is melted in CO or CO_2 and during solidification CO gas is evolved by the reaction of[C]and [FeO]ejected by the solubility changes. In the same manner, the reaction product CO is the cause of the blowholes when ferrous alloys are melted in CO, CO_2 or air. Therefore, in these cases the appearance of blowholes can be interpreted by the theory of deoxidation. In this report, only brief explanations were made on each experimental result, as hte general detailed considerations had already been reported.
東北大学の論文
1949-03-30

<研究>種々の瓦斯圍氣中に於て凝固する鎔鋼の気泡巣發生に就て

スポンサーリンク

概要

著者

関連論文

スポンサーリンク