The test pieces were taken from 20 sheets of high carbon_steels with about the same chemical composition which were made in both the acid and the basic open hearth furnace.
The test results are as follow:·-
In the normalized condition, two kinds of the tests pieces have shown about the same results with respect to the tensile test, but in the Charpy's shock test, it has been proved that the basic steel is inferior, and also that the amount of shock value depends on the coarseness and finess of austenite grains.
Further examination has been made with McQuaid-Ehn test which is used for determinings the grain size, and it has been ascertained that the grain size determined by this method indicates the inherent nature of steel, and has also been Experimentaly clarified that the steels having the same grain size show about the same physical properties independent to the kind of the steel refining furnaces used.
Finally, the result of the test with reference to the change of austenitic grain size in the process of refining, discloses that the controll of grain is necessary for the improvement of the quality of steel.

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The form of nitrogen in Cr, Ni·Cr and Ni·Cr·Mo steels, which has hitherto been almost unknown, was minutely studied by the authors with the experiment. The present method of observation is based on the determination of N₂ percentage in both HCl solution and HCl insoluble residue in the common distillation method, which change due to various heat treatments. The results obtained are briefly summarized as follow:
(1) At the quenched state, almost all the nitrogen will be dissolved in austenite or martensite of Cr, Ni·Cr or Ni·Ci·Mo steels.
(2) Tempering at high temperatures will cause most of the nitrogen to separate out as (Fe, Cr, N)₃C, i. e., almost all nitrogen atoms will be dissolved in the space lattice of Fe₃C with Cr atoms.
(3) Nickel and molybdenum have no influence on the nitrogen separation.
(4) This nitrogen separation has a critical point which occurs at the amount of Al 0·05%, i. e., when aluminium in these steels exceeds 0·05%, the phenomenon will suddenly disappear.
(5) Titanium will fix about 93% of the nitrogen in liquid steel as nitride (probably the maximum amount of titanium nitride), when 0·7% of Ti exists in these steels in a form capable of being soluble with HCl.

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Quantitative Spektralanalyse von Stahl (und Eisen) und deren Einfuhrung im praktischen Betrieb, über die theoritischen Grundlagen der quantitativen Spektralanalysen und deren Anwendung, wurde es in der letzten Zeit, v.a. in Deutschland und U.S.A. intensiv gearbeitet, und viele Veroffentlichungen darüber sind erschienen.
In unserem Forschungslaboratorium haben wir ebenfalls verschidene Versuchen über die Genauigkeit und praktische Anwendungsmoglichkeit der Methode ausgefuhrt. Als Photo-material wurde dabei ausschliesslich japanischen Platten verwendet.
Nachdem wir zur Ueberzeugung gekommen sind, mit dieser Methode die gegenwärtig üblichen chemischen Analyse ersetzen zu können, berichten wir vorliegend die Problemstellung sowie die Ausfuhrungsweise unserer Untersuchungen.

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The heat treatment, which consists of quenching steel from a temperature well over the critical into a salt bath at a temperature between 180 and 400°C and holding it there until it is completely transformed, has aroused considerable interest, because the steel subjected to such heat treatment has a better toughness at a high hardness than that found in the same steel quenched into oil and tempered to the same hardness.
The data so far published by E.C. Bain and E.S Davenport have referred only to plain carbon steel. The author investigated the effects of various alloy elements, bath temperature and holding time in a salt bath on the effectiveness of this heat treatment. Steels selected for this investigation are carbon steels and alloy steels with contents as shown in the following table.
C steel C 0·5-1·3%
Cr steel C 0·7%, Cr 1·0-3·0%
Ni steel C 0·7%, Ni 1·0-3·0%
Ni-Cr steel C 0·3-0·7%, Ni 3·0%, Cr 0·5%
Ni-Cr-Mo steel C 0·3-0·7%, Ni 3·0%, Cr 0·5%, Mo 0·5%
The results of the investigation are outlined bellow:-·
(1) This treatment is very effective for C steels of about 0·7-0·9% C, Cr steels of about 0·7% C, Ni-Cr steels and Ni-Cr-Mo steels of 0·3% C. It is not however, effective for Ni steels of about 0·7% C, Ni-Cr steels and Ni-Cr-Mo steels of about 0·7% C.
(2) The holding time in the salt both and it's temperature are carrelative, and it is desirable to hold them in salt bath until the austenite is completely transformed.
(3) In their discussion of the superior toughness of salt-bath-quenched plain carbon steel when compared with oil-quenched samples tempered to the same hardness, Davenport and Bain refer to the presence of micro-cracks in the oil quenched pieces as the probable cause of their inferior toughness
According to the author's experiments, however, no crack is found in the oil quenched pieces of these alloy steels. The author believes that the superior toughness of the salt-bath-quenched samples is due to the micro-structure which is different from that of steel quenched into oil, and also to the lower stress of transformation.

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For the determination of silicate inclusion in steel, Dickenson's nitric-acid process has been hitherto most widely adopted. In this process, however, a considerable time is taken for dissolving samples and the manipulation is comparatively tedions.
The present authors have modified Dickenson's method, and after exhaustive research attained to the Hot Nitric-acid process which is a rapid analytical method.
The general procedure of this new method is as follows:-
The sample pieces weighing about 100gms. are dissolved in HNO₃ (1:3) at about 90°C for 30 to 40min, and the excess acid is neutralized with NH₄OH. The residual silicate inclusion is treated with KMnO₄ solution and H₂O₂ as in the case of Dickenson's process. With this rapid process, one complete analysis can be finished withiu only three days, and the result is sufficiently reliable.
The authors have also adopted Sisco's electrolytic analysis for the determination of silicate inclusion in 18/8 steel or other high chromium steels, which are difficulb to be dissolved in HNO₃.

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