A hot-rolled stock after intermediate annealing and the same stock not annealed were cold-rolled at various reduction rates and then annealed at the temperature of 370°C. This is to report the change in properties of the material which were seen in the above-mentioned experiments.
The findings are as follows.
1. The more uniformed destribution of the hardness in cross section and the higher value of the hardness are obtained under the larger reduction rates. This phenomenon is the deference in the cold-rolling of coarse-grained and fine-grained aluminium sheets. Therefore, the specimen cold-rolled at larger reduction rate is softened more rapidly when it is anneald after rolled.
2. The hot-rolled stock used for this experiment has considerable working strain. It is re-crystalized when annealed at 370°C-550°C. With the progress of the annealing temperature, the grain size gets finer. In the cross section, the grain size is finer in outer part and coarser in inner part. This variety is smaller when the annealing temperature is higher.
3. When annealed after cold-rolling, it is still found that the outer part of the cross section is harder than the inner part. But, in case of the specimen being annealed intermediately, under 50per cent reduction with the reduction rate of 30-50per cent, the above-mentioned phenomenon is not observed.
This kind of change is not seemed to be made by the cold-rolling, but by the fact that the heterogenious structure of hot-rolled stock is still remained even after it is cold-rolled only by 50%, if intermediate annealing is given.
4. Generally, the recrystalized structure after cold-rolling is coarse in outer part and fine in inner part. When it is rolled at larger reduction rate, however, the structure gets finer and the difference of grain size at outer and inner parts gets small. The grain size of rolled sheet which has been given intermediate annealing is much coarser than that of not annealed.

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In the case of electropolishing of aluminium alloys, when the constituents of them are completely included in the form of solid solution in the base metal, the reflectivity willl decrease only a little but when the constituents are isolated in any form in the material, a remarkable decreasing of reflectivity will be found. Under the proper conditions of annealing and quenching, the change in reflectivity is well coincident with the metallographical diagram, becuse both of them show the limit of solid solubility.
In other cases, the change in reflectivity does not always coincide with the diagram, due to the retardation of change in structure caused by the chilling under casting.
Generally speaking, the reflectivity will decrease only a little in the case of alloys of containing less than 1.18% of copper or less than 0.45% of Mg₂Si.

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This is to report on the experiment which has been made for studying on the anti-corrosive property in white wine of anodized film on the surface of aluminium sheet.
Particularly, in case of a small part (1.78%) of the surface area being remained untreated the effect of the base materials such as 1S and 2S to anti-corrosive property of the film has been examined. The data for utilizing the aluminium alloys in wine and brandy industry has thus been obtained.

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Following the previus report on the anti-corrosive property of protective film on the surface of aluminium in brandy and white wine, this report discusses on same property of the film, produced under anodizing process by use of a mixed acid (sulphalic acid and oxalic acid), in red wine, which attacks aluminium quite hard. Particularly, the anti-corrosive effect of the surface treatment in case of a part (1.78%) of the surface being remained untreated was examined under the corrosion test in red wine.

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The anti-corrosive effect of the film on aluminium sheet, produced by the chemical treatments such as MBV process and alodine process, to white wine was reported on in the previous report. This is the report on the same effect to red wine which attacks aluminium quite hard.
It was found that the protective film thus produced was attacked by the red wine in long time but the corrosion was not very severe, so that it would be quite possible to find out the way of utilizing aluminium in red wine industry, if some more improvement could be done in this process in future.

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This is a report on the effects of extrusion conditions to structure and tensile strength of die-quenched products of heat-treatable aluminium alloys under the adequate pre-heating of billet and reduction ratio in extrusion. The tensile strength of die-quenched products was higher than that of products with similar alloys treated by the separated heat-treatment process. The grain growth-rate in product under extrusion is very rapid. As the rate is affected by the contents of grain growth inhibitors such as manganeses or chromium and also by the reduction ratio, the abovementioned factors are quite important for producing the fine-grained products under the die-quenching process. In principle, the die-quenching technique can be applied to control or to improve the mechanical property of every kind of heat-treatable aluminium wrought alloys.
But Al-Zn-Mg alloy seems to be more suitable to this process than others because this kind of alloy can obtain almost constant strength under the process, regardless of the condition of extrusion and quenching.

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Improvement of Mg-Al-Be alloy, so-called Magnox series alloys has been contemplated by adding an element of low neutron absorption cross section instead of calcium. Bismuth, zinc, tin, silicon, lead and zirconium are the elements considered. It was found through preliminary experiment that bismuth and zinc are the most effective with a view to enhance strength at the temperature of 400°C or higher. Addition of Al-Zr master alloy into the melt has also been proved to improve the strength of the alloy, but zirconium has not been detected by chemical analysis.
Work hardening curves are given and the tensile test data in Table 3. The result of the welding test under argon atmosphere is given in Fig. 2. Less softening was observed in the welded and heat-affected zones of thus improved alloys.
Corrosion test has been made in carbon dioxide gas of 8 atmospheric pressure at 400°C (Fig. 3), where, the two improved alloys have shown good corrosion resistnance.
From these tests, it was found out that the magnesium alloy, containing less than 2% aluminium, 0.01-0.05% beryllium and 0.1-0.3% bismuth or zinc could be recommended for canning matirials in CO₂ around 450°C.

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The castability of magnesium casting alloys containing zirconium is usually inferior to those of ordinary magnesium base casting alloys.
This is to report on the result of experimental work of casting mid frame, air adapter and truss ring as parts for jet engine and landing wheel hub of aircraft, for the purpose of studying on sand-mold casting by use of the said magnesium alloys.
Several different ways were applied to these trial works to find out the best way to obtain sound cast product. The soundness is inspected with the fluorescent penetrant method and the radiographic inspection methods. Then, the tests on tensile properties and impact capacity were made by use of the specimen which was taken from the products and also those separately casted. As the result of these tests, it was found out that the products thus cast had the excellent mechanical properties.
The centrifuge casting method was studied as a method for casting the products with thin wall. It was found that the numbers of rotations of mold gave the effect to the quality of products. By rotating the mold, the molten metal goes to the places where to the metal would not go the cavity when mold is not rotated. The grain is getting finer and the strength is getting better as the velocity of the rotation is increased.

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This is to report on the heat treatment of cast magnesium alloy containing zirconiu m. It was found out through the change in hardness and in microstructure and also through the differential delatometric measurement, that the high temperature and long time were required for the solution treatment of some particular kinds of magnesium alloys especially in the case that they contains rare earth metals. To obtain the maximan value of hardness by aging treatment, this kinds of alloys required higher temperature and longer time compared with other magnesium alloy castings, such as these containing aluminium, manganese and or zinc. In such case the addition of zirconium to the alloy made the aging time considerably shorter.

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This is to review on the melting and casting of 2S under the subjects as follows.
a) Hydrogen and non-metallic inclusions.
b) The treatment of melten metal.
c) Melting and casting practice.
d) Melting furnaces and casting equipments.
e) Metallurgical problemson ingot.

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