The heterogeneous reaction occurring in the course of austempering has been explained by the heat treatment diagram. The heat treatment diagram is a sort of double diagram, -a common diagram added. with a metastable one. Wether does occur during austempering any other stabilization change than the heterogeneous reaction?-it is a future problem to research.

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It has been a general practice that the C scale of Rockwell hardness tester was widely used to measure the hardness of steel balls. But, to acquire the true hardness number of steel balls, the relation between the hardness munber measured on the spherical surface and that on the plane surface should be considered. Zhe present authors introduced two assumptions, and traced mathematically the relationship among the spherical hardness, the radius of steel balls and its correction value. The result of calculation was ΔH=29.5 (l-H/160)²/γ, which was also justified by the experimental value.
Furthermore, the relation between the hardness number of steel balls gained by the Rockwell test and that by the rebounding one was shown by our experiments. In a rebounding test, the physical mechanics of the coefficient of the rebound had been little known. We, authors, presented a simple dynamic theory of the coefficient of the rebound, which might be summerized in the following expression; e=1/√l+K'K'', where K' corresponds to the coefficient of elasticity in collision, and K'' the coefficient of the permanent strain in collision. The experimental results of Rockwell tester using, concerning the coefficient of the rebound between steel balls and anvils were approximately interpreted and the coefficient of the rebound in the rebounding test was found to be nearely equal to the calculated value.

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The appearance of the striated structure of copper-aluminium light alloys was investigated in the case of various heat-treatment. The reseaches also on the effects of cold-working and content of copper were thoroughly carried out. The results obtained maybe summarized as follows: - (1) The structures of the alloys quenched at about 0°, are most remarkablly striated, even in the case directly after quenching as well as tempering. When ever the temperature of the quenching medium be higher or lower than the above case, the striation weakens and at last disappears. It is carefully to be watched that the greater the quenching effect is, the more the striation of the structure increases. (2) The hardness increases slightly followed by the appearance of the striated structure. (3) No effect of cold-working upon the striation of the structure is observed. (4) The striated structure begins to appear in the alloys containing over ca. 1.5% copper, and the more the content of copper increases, the more the striation, of the structure intensifies. Lastly X-rays analyses were carried out on the single crystals of the specimens containing 3.85% copper. From these results together with above-mentioned ones, we arrive at a conclusion that the striated structure appears as the result of the slipping along the plane parallel to the {III} face, owing to the quenching stress. Futhermore, the author confirmed in the present research that both Gayler's and Wassermann's theories, with regard to the formation of the striated structure, were not to be proper.

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Die verunreinigten Kupferlegierungen, z. B. Altmessing, Altbronze usw., die aus Maschinen-, Waffen-, und verschieclenen Metallwarenfabrihen als Abfalle im abgescbmolzercn odor nichtabgeschmolzenen Zustande geliefert werden, sind bisher im Handel frei verkauft and um Haushaltungsgegenstande oder Metallkunstprodukte verwertet worden.
Seit dem Kriegsausbruch hat der schwere Metallmangel derartigen Metallkreislauf sti eng verboten. Es gilt, these Metallabfälle zu den legierenden Reinmetallen zu regenerieren urd wieder zu benutzen. Besondets wichfig ist dabei die Erforschung and Beseitigung der Einflusses der sogenannten schädlichen Verunreinigungsstoffen.
Wir haben seit 1940 einige Versuche gemacht, Elektrolptkupfer and andere Reinmetalle unmittelbar aus Altmessing, Altbronze and anderen Altkupferlegicrungen zu gewinnen, and zwar unter Benutzung von Sulfatelektrolyt. Die technische Elektroscheideanl age für Altmessing, die auf Grund der Versuchsergebnisse gebaut wurde, fang an mit gutem Erfolg zu arbeiten and land keine nennenswerte Schwierigkeiten. Sofern die schädlichen Beimengungen, B., As, Sb, Bi, usw., nicht im besonderen ÜbermaBe in der Anode vorhanden waxen, betrug, die dadurch erhaltene Rathodenkupfer den Reinheitsgrad von 99.94% and mchr. Bei der Strenge der Lieferbedingungen fur Kathodenkupfer wird also these durch unsere Anlage gelieferte Kathode einwandfrei als “Elektrolvtkupfer” brauchbar sein.
Die andere Legierungsstoffe, d. h., Zn, Sn, Ni, usw., werden durch jede eigenartigen Prozesse in ihrereinen Zustände ahgesondert, and die erhaltene Metalle werden auch in den Waffenfabrikationen and anderen isichtigen Metallwarenfabriken benutzt werden.
Es ci uns mit Rücksicht auf die heutigen GroBkriegszustände, erlaubt, die noch nicht zur Befriedigung gekommenen Versuchsergebnisse his auf weiteres folgendermaBen zu veröffentlichen: -

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The effects of, concentration of nitric acid and temperature were examined on hard rolled aluminium (Purity=99.70%) by dip method corrosion test. The corrosion test was carried out in 5_??_98% HNO₃ at 30_??_70° by measuring the weight loss for 10 hours, and the corrosion rate was expressed as g/m²hr.
The results obtained were as follows. (1) In 98% HNO₃; the resistivity is excellent up to 70° (2) In 94% HNO₃; the resistivity is excellent at 30°, and even at 50_??_70° the resistivity is good. (3) in 92% HNO₃; the resistivity is good at 30°. (4) In bellow 90% HNO₃; the resistivity is rot good even at 30° and is minimum in. 30% HNO₃.
II. The effect of purity of aluminium was examined on virgin ingot (Purity=99.980, 99.74, 99.60, 99.38, 99.18 and 98.40%) by dip method corrosion test. The corrosion test was carried out in 30%, 90% HNO₃ at 30° by measuring the weight loss for 10 hours, and the corrosion rate was expressed as g/m²hr.
The results. obtained were as follows. (1) In cone. HNO₃ the effect of purity of aluminium is very small. (2) In dil HNO₃, the effect is small as far as purity of aluminium is above 9938%.

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A square test piece, carburized only on its one side, warps during heat treatments. We constructed an apparatus, as shown in Fg. 2, to photograph the deflection-temperature diagram of this test piece when it was heated or cooled. Two quartz rods 4, 4', push in the one end lightly the test piece at its centre and edge, and rotate in the other end the mirror 5 around its horizontal axis when the test piece deflects. A theimojunction 2, linkeed with a mirror galvanometer, indicates the temperature of the test piece. In Fg. 3, the mirror 4 and the galvanometer 2, combined with a light source, a rectangular prism and a camera, form an optical system to photograph a deflection-temperature diagram.
Using test pieces of Cr and Ni-Cr steels, we picked up from a lot, of photographs taken by this apparatus, typical ones. as in figures.
Now, in general, the. deflection may be a combination of elastical and plastical deformations. First with a view to distinguish elastical deformation, we calculated from elastic theory the deflection of test pieces, assuming that they consist of two distinct layers, the carburized case and the core, and their thermal expansion are different. The result of calculation is that the deflection is proporsional to the difference of thermal expansion of each layers. Wee photographed the diagram between the temperature and the difference of expansion of two kinds of Cr steels of 0.16% C and 0.77% C having the same Cr content, using a differential dilatometer of usual type. These diagrams are assumed to express the elastic deflection of two layers in question, the core and the carburized case. And comparing with the deflection-temperature diagrams of the test piece, we obtained the following conclusions: (1) When a test piece is heated, its carburized case suffers a compressive force above Ar', and a plastic deformation occurs. So when the test piece is cooled in furnace, the carburized side becomes concave. (2) When a test piece is cooled, in air, there occurs an elastic deformation beside a plastic one, as the carburized case becoming martensite. We solved off the carburized case of the test piece by nitric acid, to know separately the amount of the permanent plastic deformation, and to find, on comparing this remained deformation with the diagram, that the permanent- deformation was taken place when the test pieces was about 570_??_590°. (3) The aspect of the stress release at the tempering is visualized in Fig, 7.

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