Square steel bars of 15, 20, 25, 30, 35 and 40mm thick. were hot-rolled to flat bars at our small bar mill works, and measured the draught, widening, forward slip and rolling pressure.
From the data obtained, the influence of draught on widening, forward slip and rolling pressure are represented by Figs. 11, 12 and 16.

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It is a well known fact that a steel containing over 0·5% of copper may have surface cracks when it is heated above 1, 100°C and subsequently forged. With increase of the copper content above 0·8%, the surface cracks will increase in number and size.
In order to prevent this defect of copper-bearing steels, the following methods were adopted.
1) Addition of a small amount of nickel.
2) Lowering the forging temperature below 1, 090°C.
For the experiment, 34 kinds of low carbon steel ingots, each of 6kg in weight and with various contents of copper and copper-nickel, were made with a high frequency induction furnace.
They were heated above 1, 200°C and forged to 20mm square bars with a forging ratio approximately 1/10. The bars were bent in both the hot and cold conditions and tested for surface cracks at the bent portion. The results of the experiment are summerized as follow;
1) The addition of 0·2-0·5% nickel to the copper-bearing steel (0·3-1·5% Cu) is effective for the prevention of heating of forging cracks in the steel, and the higher the copper content is, the greater the addition of nickel should be.
2)The lowering of the forging temperature below 1, 090°C inhibits the formation of heating or forging cracks in copper-bearing steel e.g.a steel containing 2·0% copper and 0·5% nickel which may crack in forging at 1, 200°C can be forged without cracking at 1, 050°C.

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It is naturally of great importance that a good electrode should be used in order to obtain satisfactory results in electric arc welding. For functionating the electrode to a full scope, its manipulation must be altered in accordance with its characteristics, whilst the welding operation must be done with such arc current as to be the most suitable for the properties and diameter of the electrode, the thickness of the base metal, etc. In practice, however, the selection of welding current which is adapted for the welding condition is often neglected, and in many cases is left to the discretion of the operators.
The author has found, in his course of study on the deposit of the electrode, the fact that even under the same welding conditions the number of instantaneous short-circuits of arc varies according to the amount of arc current. Starting from this fact, he has made it clear by experiments that the best welding effects are made by the amount of arc current which causes the maximum number of instantaneous short-circuits.
In the present paper, the author proposes a simple method as obtained from these results of determining the value of arc current which may become a standard in actual welding, when the arc voltage, the diameter of the electrode and the thickness of the base metal are taken into consideration.

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The alloys of iron, chromium and copper containing less than 40%Cr and 40%Cu were investigated by means of the thermal analysis, dilatation measurement and microscopic examination, and an equilibrium diagram of the ternary system is herein proposed.
In this system there exists no intermetallic compound and a nonvariant reaction, liquid +γ α+C, takes place at 1, 085°C. The domain of γ-phase in Fe·Cr·System is enlarged by addition of cop er, so that the alloy containing 14%Cr and 5%Cu consists of homogeneous γ-phase at high temperature, and the specimen with 19%Cr and 4%Cu, α- and γ-phases. As the chromium content increases, the solubility of copper in γ-iron and the copper content at eutectoid composition decrease at first and then increase, whilst the eutectoid temperature rises gradually and afterwards rapidly.

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The author made experiments on the influence of hydrogen upon the mechanical properties of steel at normal and high temperatures, and attained the following results:-
The hydrogen brittleness, when the steel absorbed hydrogen is suddenly cooled at a temperature below the transformation point, varies as the structure of the steel. That of the coarse-grained structure, which cooled in furnace from 1, 200°C, is the most brittle in comparison with those quenched and tempered or furnace-cooled from 830°C. In each case, however, there is no change in the tensile strength and also no influence of hydrogen appears in the impact tension test.
In the case that the steeel containing hydrogen is quenched at a temperature above the transformation point, the tensile strength and the contraction of area decrease considerably, which results in easy quenching cracks and also the hydrogen brittleness appears in the impact tension test.
The experimental results at high temperature show that when the hydrogen is dissolved within the dissolution limit the brittleness does not occur at that temperature.
Even if the hydrogen is excessively absorbed at a high temperature, the hydrogen brittleness does not appear at and above the blue-short temperature.

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Since its foundation, the 19th Sectional Committee of the Japan Society for the Promotion of Scientific Research has endeavored to standardize the methods and devices for analysing gases in iron and steel. Those of analysing methods for nitrogen and oxygen were already published, and recently that for hydrogen was completed. We are very grateful in this occasion to demonstrate it.
The analysis for hydrogen may be classified into three processes, viz., 1) vacuum fusion proces, 2) vacuum heating process, and 3) combustion process. After long tedious investigations and discussions in our Committee, we finally arrived at the adoption of the vacuum heating process, referring to the existing situations in this country.
The original scheme of the process was proposed by Mr. Sasaburo Kobayasi, and the devices were designed and mainly studied by Prof. Hisayuki Somiya. In the procedure of this process, the sample of 50-100 grams in weight is heated to 800°C for 1-2 hours in a high vacuum furnace (at about 0·1-5 Hg mm). The extracted gases are analysed with Orsat micro gas analysis apparatus. The sensibility of the whole devices reaches surely below 0·01cc of hydrogen gas. CO₂ and CH₄ contained in gas are also referred to. At present, our steel works, nearly twenty in number, are adopting this process in this country.

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