By the data of basic open-hearth meltings, the relation of sulphur content between bath and slag, desulphurization velocity of ope-hearth steel and meaning of lime addition and slag off for desulphurization was studies. The sulphur content of basic slag (S) does not increase linearly as the sulphur content of bath [S] increase and approach gradually to a constant value.
Then the relation between (S)/[S] and basisity also varies with [S] content. The variation of [S] content during the smelting is representented in the next formula; d [S]/dt=-K/M[S]. This suggest that the desulphurization would be performed by the surface reaction between slag and bath and the velocity is controlled by the moving velocity of reactant in slag and bath. For desulphurization lime addition is very important, but slag off is effective to reduce the slag volume and to give the same desulphurizability.

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Some examinations concerning of the discrimination between double quenching method and Mc Quaid test (cementation method) are described. It was found that austenite grain size not satuiated on the double quenching method is generally smaller as that on Mc Quaid tes, being shown the existence of not only the contact grain boundaies but many segregation grain boundaries.
And the actually effecting grain boundaries in the steels having hardsoluble carbids are mainly this segregation grain boundaries.

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On the two series of Cr3, W 10%and Cr3, W 5%, we studied the influences of C content on the followings: (1) The trangformation point; (2) The hardness and the microstructure after water quenched from 700-1300°C; (3) The hardness when tempered at the temperatures up, to 700°C after quenched from the various temperatures above described. From these data we constituted the phase diagrams which show tbe changes of phases by the C content at the bases of Cr 3, W 10% and Cr 3, W 5%.

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Using cylindrical Ni-Fe älloy, specimens, we measured the residual stress of quenching by G. Sachs' method, and studied the mechanism of the growth-of quenching stress by changing the method of the heat treatment and the alloy elements.
By this study, we found the fact that, in comparatively low nickel alloy (16% Ni), when quenching tempsrature rises higher than thansformation point, it takes the thermal stress type (Outsidecompression, inside-tension), and when quenching temperature approaches immediately above the transformation point, it takes the transformation stress type (outside-tension, inside-compression). In high Ni alloy (26% Ni), however, no matter how the quenching temperature may be, the stress distribution takes the type of transformation stress, and its value is little, too.
As we (authors) thought the cause of the latter depends on "the transformation plasticity" as reported by G. Wasserman and E. Scheil, we made a simple experiment and could assure it to be true. In other words, in the case of low Ni alloy (16% Ni), transformation takes place it the viscous state of high temperature and the stress changes into non-elastic strain when it passes the range of transformation, so it is not affected by "the transformation plasticity". On the contrary, we may conclude that in the case of high Ni alloy, the transformation takes place in the elastic state in low temperature, so it reduces the stress by "the transformation plasticity".

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In view of the recent scarcity of pure tartaric acid the authors made a study on a rapid method of determining lime in the basic slag without using tartaric acid as with the case of usual method. The principle of our method consists in treating the hydrochloric acid solution of the sample with excessive amount of NH₄OH and ammonium oxalate solution in the presence of ammonium chloride, and, after the filtration of Fe(OH)₃, Al(OH)₃ and calcium oxalate, determining the amount of lime by titrating the excessive amount of ammonium oxalate which is present in the filtrate with 0.1 N permanganate solution. After the application of our method to the rapid analysis of lime in blast furnace slags and open-hearth furnace slags, it was proved that the maximum deviation of the results. is ± 1%, the time required is about 10 minutes, and the quantity of ammonium oxalate used is about half comparing with the case of applying the usual method.

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