For the synopsis of this work see the 1 st Report (This journal 2 (1938), 91).

抄録全体を表示

A further study on the nature of the transformation of β phase taking place at 1120° and its solubility in α phase in the system of Nickel and Silicon has been made by microscopic, X ray and dilatometric examinations, and the following results were obtained.
(1) The solubility of β(or silicon) in a solid solution decreases from the maximum value of 9.3% Si at 1120° to 6.5% Si at 900°, and finally to 5.4% Si at room temperature.
(2) The change of g at 1120° or 1118° corresponds to β₃→←β₂ and not to β₃→←α+γ as was thought in the previous paper. β undergoes two allotropic transformations at about 1120° and 1040°. β₁, β₂ and β₃ correspond to the phases stable in each range of temperatures in the order from lower to higher ones. The lameller structure in an alloy formed by a change at 1120° in the course of air or furnace cooling has proved to be due not to its eutectoid change into a and y, but to its allotropic change into β₂ which is stable between 1120° and 1040°.
(3) A change probably corresponding to β₂→←β₁ occurs at about 1040°, the rate of transformation of which is very slow. The thermal change corresponding to its transformation can scarcely be noticed, but by dilatometric measurement a large volume change is observed.
(4) The composition of the homogeneous phases β₁, β₂ and β₃ slightly shifts with temperature as seen in Fig. 2 or 3.
(5) From microscopic examination it is revealed that v phase has a small range of solubility.

抄録全体を表示

The newly designed impact torsion tester which has the capacity of 30kg-m by the initial striking speed of 1, 000 rev/min is sbown in Figs. 1 and 2, Using this tester, the impact torsion tests of three carbon tool steels were made and the results are shown in Figs. 4 to 14. Two maxima of the impact torsion value occurred at drawing temperatures of 200° and 350° and two minima at 270° and 400° Drawing up to the first maximum point is very desirable for these carbon tool steels. The fact that the impact and static torsion tests are the best method to study toughness of hard and brittle materials, is shown by the experiment (Figs. 16 to 20), and explained theoretically using the Sunatani's law of failure.

抄録全体を表示

Al-alloys containing Cu and Mg in the proportion of 4:1 or 4:1.5 and small quantities of Mn or Mn and Si were prepared and rolled into sheets. They were quenched from 500° and then aged at room temperature or tempered at 50°, 100° and 150°, and changes in hardness were measured. The addition of Mn retards somewhat the age-hardening at room temperature, but tempering at 150° gives rise to the marked hardening contrary to the Al-alloy containing Cu and Mg only. It may be due to the dissolution of Mn in Al solid solution.
The effect of Mn and Si upon the ageing of Super-duralumin was similar to that of Si. It was exlpained by the displacement of equilibrium relation from (Al), CuAl₂, Al₆Mn, Mg₂Si, to (Al), CuAl₂, Al₆Mn Mg₂Si, Si.

抄録全体を表示

The structural change of metals during tension test was studied by the x-ray back reflection method. In this experiment, it was convenient to compare the gradual change in x-ray patterns with the applied energy which could be easily known from the stressstrain curve (Fig. 7).Up to the yield point, all the Laue-spots showed the lateral elongation caused by the small distortion of the crystal plane. The photographs (Fig. 5). were taken with the cylindrical camera. (Fig. 3) and examined by the microphotometer (Fig. 6). The writer suggested that these phenomena are suitable for the investigation of yield point of metals., For specimens which show large elongation, the Laue-spots method was applied in order to obtain a continuous spectrum line from deformed specimens, but was not applicable for the study of the greater distortion in the specimen. The radial diffuseness or the displacement of spectrum lines caused by the change in crystal lattice was found in this stage and continued till the specimens were broken down. Some photographs and their microphotometer curves were given in Fig. 9 and Fig. 10, and the change in lattice constants were given in Table 2. It will be noted that all lattice distortions showed, on the average, an expansion of them, and Aluminium is a single exception whose spectrum lines remain very fine at the break down point. Lastly the writer calcluated the increase of the latent energy accompanied by the la ttice distortion following the consideration of Wood, and Haworth. The former calculated the latent energy as a heat energy and the latter as an elastic. energy. In both cases we must know the distribution of lattice distortion in the specimens which will be given by the shape of the spectrum lines, but in rough estimation the writer obtained the mean distribution(Δd/d)_av (Table 3) by the same assumption as Wood. The calculated values of the latent energy were given in the fourth and fifth columns of the Table 3 and the applied energy obtained from the stress-strain curves in the last column, The values of fourth column are too great and those of fifth column seem to be somewhat too small. It is expected to make a new consideration involving the above two.

抄録全体を表示

The macrostructures of forged steel parts such as gear blanks, crank shafts and connecting rods are considered very important, as they have direct relation to their mechanical properties and are much influenced by their ingot structures and the manners of workings.
This paper contains the results of systematic studies of the several fundamental cases of forging; the contents of it are as follows;
I Introduction.
II The relation between the dendritic figure and the forging ratio of steel ingots forged parallel to the direction of their length.
a) Carbon Steel.
b) Nickel-Chromium Steel.
III The relation between the dendritic figure and the reduction ratio of specimens cut out from thee ingot having nearly the same structure when up-setted to the fixed direction of the axis of cast crystals.
a) Carbon Steel.
b) Nickel-Chromium Steel.
IV The influences of soaking before forging on the dendritic figure.
V The change in dendritic figures of pieces cut out from the ingot having nearly the same structure when forged again to the original shape after being up-setted to the fixed direction of the axis of cast crystals.
VI The relation between the macrostructures of different size of forged bars and their forging ratio.
a) Making of test pieces.
b) The macrostructures of the different sections of test pieces.
VII The relation between the mechanical properties of the tested samples and the forging ratio and the macrostructure.
VIII On some practical examples of forged pieces with complicated shape.
IX Conclusion.

抄録全体を表示