No satisfactory method of measuring temperature of a steel bath, when in the open-hearth-furnace or the arc-furnace, has yet been devised.
Usually, for convenience, the temperature of steel baths is conjectured indirectly from the values that obtained by an optical pyrometer as the temperature of the liquid steel in the spoon at sampling. This procedure is, however, quite unreliable, in accordance with the lack of knowledge about the personal error of an observer, the emissive power of liquid steel in the spoon, a fall of the temperature of the spoon under ladling from the furnace, etc., that we can hardly know the accurate temperature of the steel bath.
The author has attempted to improve the method and has made several studies on the points just mentioned above. The results are as follow:
1) The personal error was determined by the simultaneous use of a standard lamp and a standard optical pyrometer. In addition to this, the degree of skill of the observer was assumed from the dispersion of data.
We cannot neglect the effect of personal errors which attain ±10° in the maximum.
We find also that the degree of skill of the observer does not depend neither on the age nor on the duration of practice.
2) The true temperature of liquid steel in the spoon was measured by the special Fe-W thermocouple, which was of a direct immersion type and formed a hot junction through the liquid steel. The heat capacity of this thermocouple is very small and the measurement can be finished in 3-5 seconds.
We compared the true temperature by the Fe-W thermocouple with the brightness temperature by the optical pyrometer, and obtained the emissivits of each kind of steel in the spoon. Namely, in case of the arc-furnace, the average values are 0·55 for Ni-Cr steel, 0·56 for Cr-Mo steel, 0·53 for Ni-Cr-Mo steel and 0 52 for carbon steel In the case of the open-hearth-furnace, where the data are not enough, the total average value is 0·52.
3) The cooling of the liquid steel in a spoon during ladling was determined from the evaluation and the experiments. The fall of temperature is affected by the thickness of slags which cover the spoon. While the thickness of slags varies from 0·4 to 1·0cm, the fall of temperature takes the value from 40 to 20°C.

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The authors studied the effects of Cb on the phisical mechanical, chemical and welding properties of low carbon Cr-Mo steels and medium carbon Ni·Cr steels.
The compositions of the samples are as follow:-
From the experiments, it was concluded that Cb is a valuable alloying element for low alloy steels and it has several advantages such as inhibition of air hardening characteristics, increase in strength at high temperature, increase in corrosion and oxidation resistances and improvement of weldability, although it lowers the impact value more or less. But it is questionable how much it may be used in the industrial scale because of its high cost.

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