We have studied on the effect of the stress relief of the casting stress induced by the casting of cast iron through the mechanical vibration of castings.
The castings were clamped directly on the vibrating disc.
The frequency of the vibration disc were varied from 1000 to 4000 cycles per min.
The amplitude of the vibration disc was set at 1mm constant.
The treatment times were 48 hours constant.
The specimens were made considerably big by casting, and the effect of vibration seasoning was measured by the relative displacements of the gauge length, which was 100mm at the standard state (When the specimens were annealed at 600°C).
We have obtained the following facts from the experiments.
(1) The effect of the vibration seasoning is proportional to the frequency of vibration.
(2) The direction of vibrating of casting has little relation with the direction of casting stress of the specimen.

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Through the present investigation, the effect of temperature of torsional working on the torsional creep strength of 18-8 stainless steel has been obtained. The specimens were twisted to a degree of 0.128π/cm or 0.256π/cm at several temperatures from-60°C to 800°C beforehand, and then their torsional creep strengths for 450, 500 and 720°C were measured.
The torsional creep strength increases as the temperature of torsional working rises, and reach the maximum for the specimens worked at 300-600°C.

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When the coating using calcium rosin as a basic ingredient comes in contact with solvents, it shows “solvent-cracking” which is peculiar to high polymers, and thus the cracking of coating occurs at lower stress than in air.
Therefore, strain sensitivity of brittle coating has been improved by applying solvent-cracking, and the experimental strain analysis has become very easy.
A few theories such as spherulitic aggregate and others, has been introduced in high polymers as mechanism of solvent-cracking.
Since the molecular structure of brittle coating is different from high polymers, it is doubtful whether the mechanism may be applied to brittle coating even if the above theory has been established.
Through the structural model which was observed in the previous report, the author has assumed and investigated systematically a few mechanism for the cracking.
From the result, the mechanism of solvent-cracking on brittle coating is concluded as follows; when the coating comes in contact with solvents, its components, rosin acid and pure calcium salt, show such a different degree of swelling that tensile stress occurs transitionally in brittle coating.

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This is a report on an investigation about the chemical composition, mineralogical structure and physical properties of the stabilized dolomite clinkers which are to be used as basic refractories. SiO₂, Fe₂O₃, Al₂O₃ are added to dolomite ore as stabilizers and burnt at 1520°C. These materials are analysed by a chemical and mineralogical method. These stable clinkers consist of periclase and tricalcium silicate, and a dicalcium ferrite is produced with some amount of Fe₂O₃, Al₂O₃ also produces tricalcium aluminate. Both dicalcium ferrite and tricalcium aluminate have a low melting point and accelerate sintering properties. In consequence of this effect, apparent porosity decreases and compressive strength at room temperature increases. As the compressive strength extremely decreases above 1200°C, they are not suited for refractories. Material 5-9, 12 in Table 4 have excellent properties and suited for long storage. We suppose this effect is caused by existing tricalcium silicate and periclase.

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In the present report we have experimented on the bending fatigue strength of glued-laminated wood which is made of Japanese cypress and is glued with urea resin or phenol resin. For comparison, same experiments have been carried out also on solid Japanese cypress and beech with controled moisture content and air dried. Also we have made consideration on the fatigue notch factor on these specimens having two kinds of holes. These researches have been done by the Nishihara's Fatigue Testing Machine for Repeated Bending of Plate.
The results obtained are as follows:
(1) The fatigue strength of flatsawn grain specimens is a little larger than that of edge grain specimens in most cases.
(2) The glued-laminated wood with urea resin excels that with phenol resin in fatigue strength.
(3) The fatigue strength of the glued-laminated wood with urea resin is 1.4 times larger than that of solid wood at the 10⁷ cycles, and also that of phenol resin is 1.3 times.
(4) The fatigue strength of the specimens with holes of diameter d=7.1mm is larger than that of 2.6mm.
(5) The fatigue notch factor for solid Japanese cypress is smaller than 1. And that of glued-laminated wood is smaller than 1 or approximately equal to 1.
(6) The specimen of solid Japanese cypress having a small hole with a diameter of 2.6mm is not influenced with the hole in fatigue strength.
(7) The glued-laminated wood specimen having a small hole with a diameter of 2.6mm is not influenced in the fatigue strength at low stress levels.

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