Degree Of Deoxidation Research Articles

セミキルド鋼塊の巨大介在物におよぼす脱酸度および耐火物の影響

セミキルド鋼塊の巨大介在物におよぼす脱酸度および耐火物の影響

銀点の成因に関する二,三の冶金考察

Authors surveyed the influences of three different methods (JIS, modified ISO and ISO) for the tensile test of deposited metal-in the former two, in as welded condition and in the latter, after hydrogen removing treatment, the test is carried out-upon fisheye appearances and mechanical properties of deposited metals from various types of mild steel electrodes, and further investigated some metal-lurgical properties of deposited metals.From the experimental results, authors found that fisheye appearances revealed in ordinary strain rate at room temperature are influenced by the deoxidation degree, the diffussible hydrogen content existing in time of test, the size and number of porosities in deposited metal.

セミキルド鋼について二,三の研究(I)

A number of test ingots weighing about 4 tons were made of semi-killed Steel of C: 0.16-0.25% and Mn: 0.34-0.54% by applying widely different degrees of deoxidation. Taking a test-piece from the corner of each of these ingots, an investigation was carried out of the conditions of blow-holes: the relations between the degree of deoxidation and the number, the size, the position and the distribution of blow-holes were tried to be nade clear.Further, a study was made also about the mechanism of blow-hole formation. After studying quantitatively the roles of CO, H2 and N2 to be played about formation of blow-holes, it was concluded that in case of semi-killed steel, no small care must be paid not only to the degree of deoxidation, but also to H% in moltem steel, inasmuch as that the stronger the degree of deoxidation becomes, the more the CO% in the composition of gas will get decreased, and when the deoxidation is raised so much that almost no blow-holes will come about, the gas composition will be CO: about 30%, H2: about 60%, N2: about 10%.

熔鋼の脱酸に關する二,三の研究

(1) Direct deoxidation of molten steel by manganese was experimented, obtaining the following formula for the solubility of MnO, in which the sample had been skimmed from the molten steel with a specially designed quartz apparatus and quenched immediately in mercury, and the MnO and FeO in the steel had been analysed by the alcoholic iodine method:-Solubility of MnO (%)=1·5×10-4t°-0·198. For instance about 0·05% MnO dissoives at 1650°C and the following deoxidation equilibr%ium:[FeO] in steel+[Mn] [Fe]+[MnO] in steel.(2) In case where silicon was added to the molten steel, an acidic SiO2 cvolves, absorbs MnO and floats off. Therefore the abovementioned equillbrium disjoins, causing the reaction to the right alone. In other words, in case of the coexistence of silicon even the small quantity of the manganese content participates in deoxidation, being effective to the elimination of SiO2. In practice, a sample was taken with a vacuum sampling vessel from the mollen steel at the deoxidation period in the acid open hparth refining, the analysis of which yield an extremely slight quantity of SiO2 as the deoxidation product.(3) A considerable amount of Fe-Si or Si-Mn was added to about 2kg of the molten steel with 0·2% Mn and solidified within some minutes. From the results of a number of such experiments, it was found that steels with above 0·35% Si contain below half amount of the silicate inclusion when compared with those with about 0·20% Si. Similar results were obtained in the melting teat on a larger scale.(4) It is presnmed therefore that, the deoxidation degree of the molten steel may be improved and the silicate inclusion of ingots may be lessened by suitably utilizing the method of adding considerable amount of silicon to the molten steel with above 0·2% Mn.

半鎭靜鋼塊に於ける氣泡に關する研究

The author studied on the relation between the positions of the blow-holes and the thicknesses of the ingot-moulds for the incompletely "Killed" steel ingots. And consequently it was deduced that a slightly good influence recognized by increasing the thickness of the ingot-mould. From this experiment, the author also explained the mechanism of the occurrence of the blow-holes, and that the important point of smelting of this steel is "the moderate deoxidation degree and the supercooling of the molten steel on the solidification"