The mineral composition and texture of the scaffold sample, taken from the shaft of Higashida No 4 BF were examined and the formation mechanism of the scaffold was discussed. Determined minerals were wüstite, a'-dicalcium silicate, periclase, merwinite, sulfide, carbon, potassium magnesium aluminium silicate and alkali aluminium silicate. The latter two were regarded to be new species. In the loose part of the scaffold considerable amounts of dicalcium silicate and potassium magnesium aluminium silicate and in the dense part large quantities of merwinite and alkali aluminium silicate were found. The formation process of this scaffold is discussed as follows: The particles of dicalcium silicate, potassium magnesium aluminium silicate, periclase and some sorts of minerals in the system of Na2O-Al203-Si02, which are not directly originated from the charged materials, are deposited on the wall of the furnace together with iron oxide particles. After the temperature is elevated, the accumulated mass of the mineral particles changes to a dense body by sintering with the generated liquid of the system of Na20-Al203-Si02, and at the final stage of sintering merwinite and alkali aluminium silicate come to compose mainly of the scaffold.
Densities of iron oxide melts in equilibrium with CO2-CO gas mixtures have been measured by the Archimedean method employing the double-bob technique. The explored temperature range is 1450 to 1525°C and composition range is Fe3+/ΣFe=0.093 to 0.358. At constant temperatures densities of the melts decrease with increase of Fe3+ content. At higher Fe3+ contents this decrease of density becomes more gradual. At constant compositions densities decrease linearly with increase of temperature. Expansivities of the melts decrease with increase of Fe3+ content. The results are interpreted with a proposed model on the constitution of the melts. It is pointed out that oxygen ions are much more closely attracted to Fe3+ than to Fe2+ and this is responsible for the trends in the relations of both density and expansivity with composition.
This paper presents a design calculation of the continuous casting of metals. Fundamental equations given in relation to the unidirectional transient conduction in the water-cooled mold zone and in the spray-cooling zone have been solved analytically with the several simplified assumptions. An important dimensionless factor H2 which determines the quantitative correlation between the length of the cooling zone and thermal diffusivity, thickness and moving rate of the ingot are obtained from calculation based on the solutions. In the case of casting steel ingot, it is found that the numerical value of H2 may not be influenced largely by the ratio of the length of copper mold to the total length of cooling zone, the wall thickness of the mold, heat transfef coefficient in the spray-cooling zone and the thickness of the ingot. Estimated values of residence time in the cooling zone for the various values of the slab thickness are good agreement with the several operating data reported hitherto.
The temperature dependence of the internal friction and the shear modulus of several iron binary alloys (alloying elements: C, Co, V, Al, Ti, Zr) was measured under cold-worked and primarily recrystallized condition. Some resemblance was seen between the temperature dependence of as-cold-worked internal friction or shear modulus and that of as-annealed. The effects of the alloying elements on the so-called grain boundary internal friction phenomena are as follows: 1) With increasing size-factor and content of the alloying element, the activation energy of the solvent peaks and the solute peaks increases. 2) If the size-factor is large, even a small addition of the alloying element causes at ransition from solvent peak to solute peak. 3) The alloying elements increase half-value width of the peak. 4) The correspondence of the internal friction peak height and the 4M effect is missed in some cases. In place of the grain boundary sliding model which has many difficulties on its application, a new mechanism was proposed based on movement of the sub-boundary dislocation or migration of a special boundary i. e. a coincidence site lattice boundary on which sub-boundary dislocation net-work is superimposed.