Kleine Magnetitstücke von etwa 8gr. wurden mit Koksabrieb bei verschiedenen Temperaturen über 800°C bis 1, 300°C reduziert und folgende Resultate erhalten.
Die Reduzierbarkeit von Magnetitstücken bei niedrigen Temperaturen z.B. unterhalb 1, 000°C ist gering. Man muss bei Temperaturen über 1, 200°C reduzieren um gut reduziertes und dichtes Schwammeisen zu erhalten. Schwammeisen, das bei 1, 050° bis 1, 150°C reduziert wurde, hatte das grosste Völumen von 108% des Erzes und die grösste Porositat von uber 40%. Das bei 1, 300°C erhaltenes Schwammeisen hatte ein Volumen von 90% des Erzes und eine Porositat von 37%.

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agnetit von etwa 3kg wurde mit Koksabrieb eingepackt und bei verschiedenen Temperaturen über 1, 000°C reduziert, um dadurch intressante Einsicht in Bezug auf den Verlauf der Reduktion des Groberzes zu finden.
Die Reaktion der Formel Fe₃O₄+CO=3FeO+GO₂, die mit grosser Geschwindigkeit von der Oberfläce des Erzes bis in das Innere verläuft, bewirkt so dass ganze Teile des Erzes bald in Wüstit umgewandelt sind. Dagegen kann die Reaktion nach der Formel FeO+CO=Fe+CO₂ in den inneren Tei en des Erzes nicht ohne weiteres vor sich gehen, so dass das Erz nach einer bestimmten Reduktionszeit in eine Masse übergefuhrt ist, deren Oberflache aus eiuer metallischen Schicht und deren Inneres aus Wüstit besteht.
Die Maximaldicke der metallischen Schicht kann bei einer Reduktionstemperatur von 1, 000°, 1, 100°, oder 1, 200°C, etwa 10mm nicht überschreiten, obgleich wie lange das Erz bei einer bestimmten Temperatur behandelt wurde. Jedoch kann man die metallische Schicht durch Reduktion bei langsam oder stufenweise steigender Temperaturen noch sehr verstärken, und so auf eine Schichtdicke von über 25mm kommen.

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The author tried to roast the crushed pyrrhotite to use the cinder as an iron resource, and also tried to learn why the ore can not be used as a sulphuric acid resource. In these tests, the author roasted the ore by passing definite volumes of air and the oxygen-rich air, and also tried roasting in the thermobalance, and analysed the gases therefrom. We obtained the following results:-
(1) Almost all sulphur dissociate at temperatures below 900°C, but when we used the oxygenrich air it dissociated at the temperatures 100°-200°C lower.
(2) When we roasted the ore in the thermobalance, we observed the dissociation of sulphur at temperatures from 150° to 1020°C, but for pyrite it was 400°-650°C.
(3) Pyrrhotite cinder contains the high iron, the low sulphur and accompanies some cobalt and nickel.
(4) In the analysis of roasting gases we found that the sulphur dio ide concentration is equal to that of pyrite, but the SO3 is higher.

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At the Fuji Iron Works of Japan Iron Mfg. Co., Ltd. (Nippon Seitetu K.K. Fuji Sei-kosyo), a steel making by means of the cold-pig-ore process (85-90% pig) has been practised as a normal working, with the fixed basic open hearth furnace since January 1941. The purport of the present process consists in preparing the suitable raw material and overflowing naturally the first superfluous slag by uulizing the expansion of slag during the melting period. According to the present process and the like informed so far, it is not only possible to reduce the slag quantity remained in the furnace and the total quantity of slag formed, but also to oxidise and eliminate most of impurities in the raw material before the melting down period. In this manner, the purpose of the reaction of preliminary purification was almost attained, and so the operation of steel making by the cold pig ore process facilitated the more.

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The attack of hydrogen on the carbon steel with varying carbon contents at elevated temperatures and under high pressures and the effect of alloying elements were'experimented. In carbon steels at the constant temperature of 500°C and under different pressures ranging from 50 atm. to 300 atm., the steels were sever ?? ly attacked by hydrogen and suffered a remarkable decarburization, fissure formation. and decrease of mechanical properties and, above all, they become ductile under 200-300 atm. Such attacks were much pronounced in the Ligher carbon side. At 100 atm., the attack of hydrogen was less prominent than at 200-300 atm., and there was a tendency that the lower carbon side was little more attacked than the higher carbon side. At 50 atm., the. attack was almost neglible. Moreover, the experiment was extended to 0·1% and 0·6% carbon steel at varying temperatures from 350°C to 500°C, and respectively under 100, 150 and 200 atm, pressures. The temperatures at which the remarkable attack of hydrogen was observed were 450°C at 100 atm., 400°C at 150 atm., and 350°C at 200 atm. It was presumed that the 0·1% carbon steel was less attacked than the 0·6% carbon steel with the rise of temperatures and pressures. Being based on the aforementioned experiments that were the result of the author's actual factory test, the temperature-pressure-stability limiting curve of carbon steel against the hydrogen attack was plotted as shown in Fig. 13.
As for the effect of various alloying elements on the hydrogen attack, it was classified into the following three groups:
(1) Elements which do not form carbide such as, Ni, Si, Al and P.
(2) Carbide forming elements, which are soluble in Fe3C, such as, Mn, W, Mo and Cr.
(3) Special carbide forming elements such as, V, Ti, and Cb.
Some of the elements which do not form carbide, such as Ni, Si and P, were apparently beneficial, but Al showed some resistance Among the carbide forming elements, Mn revealed a little effect; W, Mo and Cr were positively effective with the increase of contents, and in the same content, the order of prevalence was Cr, Mo and W. Cr showed favorable effect at the percentage more than 15 times of the C content and than 20 times of the C content, respectively at 500°C under 200 atm., and 500°C under 300 atm. The 1% Cr-Mo steel. was attacked severely by hydrogen at 500°C under 300 atm., but showed good resistance at 500°C under 100-200 atm. Among the special carbide forming elements, V, Ti, and Cb were much more effective than W, Mo, Cr and favorable effect was observed when V/C was >6, Ti/C was >4, and Cb/C was>10. It may be concluded that all the effective elements were within the 4th, 5th, and 6th groups and below the 4th period of the periodic system of elements; and that, in the same groups and periods, the preceding elements were more effective than the following.

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