Effect of silicon on the quality of structural low-alloy nickel steels melted in the acid open hearth furnace was studied and the results were as follows:
(1) The silicon contained in steel produce a remarkable influence and the silicon in excess of about 0·23% causes a visible change in mechanical properties, grain size, hardenability and transformation-velocity.
(2) As compared with steels with less than 0·23% Si, those with more than 0·23% Si have more refined grains, better hardenability, and when the larger sections are heat treated, the mechanical properties (particularly, Izod impact value) in the core are especially higher.
(3) The macrostructure of the forging varies with the silicon content, Steels with less than 0·23% Si consist of dendrites and granular, masses while those with more than 0·25% Si are formed into a uniform structure of dendrites alone.
(4) The quantity of sand inclusion has no reference to the silicon content in the range of 0·15-0·35% Si, but the silica tends to decrease remarkably with the enhancement of the silicon.

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Among some kinds of raw iron made with the rotary furnace, sponge iron and loop (Luppe) belong to the principal material for steel making which may be treated similarly to scrap iron. A third product which may be regarded as the intermediate between the two can be manufactured in the actual rotary furnace operation. It is tentatively called a "Karuisi-tetu" (pumice iron). The three kinds of raw iron e.g. sponge iron, pumice iron and loop were compared as regards to their industrial characteristics and the following conclusion was obtained:
The manufacture of loop is the most rational among several rotary-furnace methods and the simplest in the smelting operation. The loop manufactured under suitable conditions and in a perfect process of production, has no defect when used as material for steel making, There is no better grade of raw irons that is not dependent on the scrap iron. However, the grade of the final product of loop depends on the method for its manufacture. Therefore, a more effective development in this line should be found and some unfavorable criticisms on the loop hitherto produced would be dispelled if a standard specification for its composition is formulated.

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Die Austenit-Korngrösse ist eine wichitige Moment der Eingenschaften des Stahles. In den letzten Jahren, so sind manche Untersuchungen auch in Japan geleistet geworden. Aber als die Darstellung der Korngrösse, die uns den Anhalt der Untersuchung geben und das Resultat des Experimentes quantitativ zeigen soll, hat man bis jetzt verschiedene Methoden aufgenommen, aber gab es keine bestimmte Resultat. In diesem Berichte, deshalb handelt der Verfasser erstens statistisch diejenige Darstellung ab und gibt eine rationale Methode an. Zweitens vergleicht er vier Austenit-Korngrösse entwickelnde Methoden (zum Beispiel, Einsatz-, der Oxidations-, der Salzbades-, und Doppelhärtungsmethode) und äussert ihre Stärken sowie Schwächen.

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Tests were conducted with the object of verifying reports that the mechanical properties of steels made from spongy iron excelled those of steels made from scrap iron. In Experiment I, as a preliminary test, comparisons were made of the mechanical properties of carbon steel made from the two methods just mentioned, for which purpose from five to six suitable kinds of this steel with carbon contents ranging from 0·2% to 1·3% were selected ahd tested. Contrary to expectations, the steel made from scrap iron was found to be tougher and harder.
According to Experiment II, the mechanical properties of steels made from the two processes and with the same range of carbon contents as in the preccding experiment, under five different heat treatments, were compared with the same results as in Experiment I, except that the steel made from spongy iron, although tough, was clearly found to be inferior in strength.
In Experiments III and IV, the same comparative tests were made with nickel-chrome steel of thirty different compositions and under seven different heat treatments, with the result that the steel made from spongy iron was much tougher and harder than that made from scrap iron.
In the foregoing Experiments I-IV, the test-pieces were obtained from ingots weighing 9kg each, and tested for tension and impact. In Experiment V, which was supplementary to the others, the test pieces were obtained from ingots weighing about 230kg, the experiments being for torsion and fatigue, and for their mechanical properties at high temperatures. The foregoing experiments amply proved the higher mechanical properties of steels made from spongy iron than that of steels made frotn scrap iron.

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Coke furnaces with a by-Product collection unit in Japan had depended entirely on importation up to Taisho-7 (1918), when the "Kuroda" system coke furnace was developed. Since then the coke furnace in Japan has made a further progress in competition with other excellent furnaces of foreign design and attained to the present eminence in parallel with the remarkable progress of the iron, gas and chemical industries.
The "Ono" system coke furnace has experimentally improved the heating method and the heat efficiency of the common furnace. Its main features are as follows: a better design of connecting the heating flue with the recuperating chamber; improved and stronger structure of the recuperating chamber; ease in the control of proper heating temperatures in accordance with the width of the furnace; the least freedom from the pass resistance of the heating or exhaust gases; and increased heat efficiency of the recuperating chamber.

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