Temperature distributions in Three-pass stove and two Cowper stoves of different design in details at Yawata Steel Works, firing, gases and airs supplied to them were measured. From these results, heat efficiency of each hot stove was calculated, and firing gases were compared with the hot airs used to the blast furnaces. Moreover, actual amount of hot airs given, to the furnaces and produced gases recorded by each gas-meter, real amounts of them measured by the method of Pitot-tube and true values of them caleulated from ores and others are examined.

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During recent years our open hearth furnaces have been improved on their construction & practice. The total heat consumption per ton of small ingot is reduced to 125×10⁴ or 105×10⁴ calories; equivalent to 120-100kg of heavy oil. The Heat from the coke oven gas account for 70% of the total heat & the remain is fed with fuel tar. Our furnaces could wark with liquid fuel only or gas & liquid fuel efficiently. The open hearth furnace efficiency depend on the several condition & facters, but the Size of cheeker chamber & chimney are considered of paramount importance for practice e.g. larger Size is better. The article describes our practical features & some investigation with many tables & figures.

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The phase boundaries in the equilibrium diagram of aluminium and chromium alloys, containingup to about 50% of chromium, have been determined by the thermal, fusion, and microscopic analysis between 450° and 1, 100°C.
Three peritectic reactions were ascertained to take place at 1, 018°, 803°, and 660°C., where two chemical compounds, having the compositions of Al2Cr and Al4Cr, and a solid solution are formed, respectively.
The limit of solid solubility of chromium in aluminium at 640°C. was found to be between 0·67 and 0·80%, and the value is constant as the temperature fal1s down to 470°C.
Rolled sheets of the alloys, containing up to 1·6% of chromium, were subjected to mechanical and corrosion tests after heat-treatments. The tensile properties slightly rise as the chromium increases. The alloy of about 0·7% of chromium showed remarkably higher tensile strength on the annealing than those of surrounding compositiomls.The phenomenon was assumed to, probably, be due to its higher recrystallization temperature than the others.
Corrosion tests were carried out by the "alternate wet and dry" method in the artificial sea water for a month, and the corrosion which occured was observed by change in mechanical properties.
The samples of about 0·7% of chromium, which had been annealed, were found to be exceptionally resistant comparing those of surrounding compesitions, and even better than the annealed pure aluminium.
Corrosion resisting property of this alloy of particular composition which has been annealed seems worth while to be considered in connection with its abnormal high tensile strength stated above.

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Experimbental equipment, similar to that adopted by Petersen (Archiv. Eisenhuttenw. III, 1930, 459) but somewhat modified, was used for this investigation-The sample was a cylindrical block having about 10g. As alloying metal, tin or gold was used. The reduction temperature and the temperature of the nickel-thoria catalyst was kept at 1200°C and 250°C respectively The blank value to be reduced from the observed value obtained in the usual analysis was determined as follows:
In the first weighing tube, 0·074mg per hour at 1, 250°C.
In the second weighing tube, 0·080mg per hour at 1, 250°C.
Armco iron was first accurately analysed for its oxygen to be used as the standard sample for the following experiments. Silicon, manganese, nickel and chromium in the state of metal or ferro-alloy were then melted together with the standard sample. From the results of this investigation, it was confirmed that nickel has no influence on the results of the Ledebur method adopted here. It was also found that the complete reduction of the deoxidation products such as SiO₂, MnO or Cr₂O₃ by hydrogen in this process is not imposible, although it requires a very prolonged time. This phenomenon was simply explained theoretically.

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