In these days of marked introduction of light metal parts, such as of alminium alloy, in mass production with a view to rationalizing production and lightening machine parts, studies on the machinability of alminium alloy are few in number as compared with those on steel and iron. Generally, in most of studies on the machinability of materials, machinability in turning has heretofore been made a subject of study, and machinability in drilling or milling has been done so in very few studies. In the case of steel and iron, there appears to be some relations between machinability in turning and that in drilling, but whether the similar relations are existent in the case of aluminium alloy or not, no one has so far been able to tell for certain.
In the present study the machinability in drilling of wrought alminium alloy, i. e., 2S, 11S, 17S, 24S, 52S and 56S, was experimented and the machining data and machininig characteristics of alloy were looked into. The machinability in drilling is usually to be determined based on various factors, for instance, drilling resistance, the life of tools, the roughness of drilling surface, chip formation, chip disposal and others. There seem to be two types of drilling: drilling under constant feeding speed and drilling under constant drilling load, if automatic production is put under consideration. In this paper there are treated drilling resistance, the roughness of drilling surface and chip formation in the case of drilling under constant feeding speed.
The resultsare that the machinability of 11ST4 alloy is superior. Those of the others run worse and worse in the order of 56SF, 24SF, 17SF and 52SF, and the worst is the machinability of 17ST4, which, however, is characterized in that machining can be easily effected if pre-drilled.
The author would offer his grateful thanks to the Scholarship Committee of the Institute of Light Metal Foundation for the pecuniary help given him in connection with the completion of this study.

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Carbon was added to aluminium, using metal carbides; such as manganese carbide or high carbon ferromanganese. Microstructures, macrostructures and mechanical properties were examined. The results obtained are summarized as follows:
(1) Carbon is easily alloyed by this process even in air.
(2) In the Al-C-Mn system, carbon is non-existent as either simple aluminium carbide or manganese carbide, however it possibly exists as complex carbide.
(3) Al₃ Ti phase in the Al-Ti system and in the Al-Ti-Mn system disappears by the addition of carbon and a new phase is assumed, which appears to be that of Ti C compound.
(4) The Be phase in the Al-Be system and in the Al-Be-Mn system disappears with the addition of carbon and a new phase is assumed which is believed to be complex carbide.
(5) In the Al-B system and in the Al-B-Mn system, a new phase also appears by the addition of carbon.
(6) The grain size of lautal becomes coarser by independent additions of carbon or boron. When carbon and titanium are added simultaneously, the carbon has a tendency of making the grain size coarser, which had becom fine by the addition of titanium. When the titanium and Boron are added simul taneously and the quantity of boron is greater than the titanium, its grain size becomes coarser.
(7) The mechanical properties of chill cast lautal do not change by independent addition of carbon or by simul taneous addition of titanium and carbon.

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The experiments were carried out on the damping capacity of aluminium cast alloys prescribed in JIS H 5202 as 15 sorts and 31 qualities in order to find out relationships between the damping capacity and the fatigue life in repeated torsional oscillation, and to make comparison between the results thereof and the various properties already measured by the Aluminium Cast Committee.
In this paper, 1AF, T6; 2AF, TG; 2BF, T6; 2CF; 3AF; 4AF, T6 and 4CF, T6, T5 each in its cast alloy are examined. The results are that the fatigue strength determined under constant repeated stress does not always agree with the fatigue life determined under constant repeated strain. The damping capacity and the fatigue life are in lever relation with each other. The materials which have good fatigue life are 2BF, 2BT6, 4BF and 4BT6, while those having poor fatigue life are 4AF and 4CT5.
The other matirials stand midway between the above two groups. The materials which have good mechanical properties are superior in fatigue strength, but their inclination is not so very correlative.

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The effect of nickel on change in measurement by heat treatment, such as solution treatment an tempering, was researched into by the dilatormeter method.
The results obtained are as follows:
(1) Change in measurement was found on allows with or without nickel as under:-in the T4 treatment alloys were contractible as against cast alloys, in the T5 treatment alloys were expansible as against before treat ed, and in the T6 treatment change in measurement was hardly found both before and after the treatment.
(2) In the T4 solution treatment less contraction was found on alloys containing nickel than on those without nickel. The T5 treatment showed that expansion to occur on alloys containing nickel in artificial aging at 200°C was less than that on alloys without nickel. In the T6 treatment contraction brought about by a solution treatment and expansion occurring in artificial aging could be controlled by way of containing nickel, but change in length was hardly found both before and after the treatment on alloys with or without nickel

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Colored, thick oxide films are produced on aluminium by anodic oxidation in the non-aqueous system of boric acid-formamide.
The films are hard and compact and the color tone changes from yellow through brown, to black, as the film becomes thicker. The properties and mechanism of formation of the films were investigated by chmical, electrochemical, physical and optical means as well as by X-ray analysis.
It is of interest, that boric acid dissolved in water, gives barrier type films, while the present solution gives thicker films.
Actually, the film may be regarded as of intermediate nature between barrier and duplex type anodic films hitherto known. For anodic oxidation, a saturated solution of boric acid in formamide was found preferable.
The film may be classified into two groups: (1) Low current density film (0.5A/dm²) which is of organo-metallic nature (Al(HCONH)₃), soft and rough, (2) High current density film (2-4A/dm²) which consists of Al₂O₃ and B₂O₃, being hard and compact. With the aid of the previous information (S. Tajima and N. Baba, Electrochimica Acta 7 355, 1962), the mechanism of formation of such films were clarified. Corrosion and abrasion resistance and light-fastness were confirmed by laboratory and out-door exposure tests.

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One of drawbacks that aluminium alloy pressure vessels have suffered so far is attributed to the fact that the standards for the manufacture and the regulations in use are accordance with those for steel vessels. The only aluminium alloy which is approved for pressure vessels is 2017-T4, and their exploitation is restricted within carrying oxygen, nitrogen, carbon dioxide and air.
This state of affairs caused incovenience on the part of the administration of industrial safety and, on the other hand, the demand for pressure vessels of corrosion-resistant aluminium alloy has been raised by the users.
In March 1962, the competent authority suggested that a set of specifications should be drawn up for use of the other aluminium alloys for gas cylinders independent of customary circumstances and taking advantages of the characteristics of light metals, and consequently, the committee of Light Metals for Pressure Vessel was established in Light Metals Society. This report is a summary of studies that the committee has made carrying out various tests, such as, hydraulic stretch, alternate pressure, hydraulic breaking, repeating drop-impact and crushing tests, on the seamless cylinders of six kinds of materials having 7 litter capacity.
The dimensions, the chemical compositions, the mechanical properties and the test procedures are shown in Table 1, 2, 3 and 4, respectively, and various test results are summarized in Table 12 compared with 2017-T4 cylinder.
According to the above mentioned results, 5052-F, 5056-F, and 6151-T6 alloys are not inferior to 2017-T4 alloy as cylinder materials. The proposed specifications and the allowable stresses are shown in Table 14 and 15 respectively, and the standard of safty factor can be taken 3, approximately.

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In March 1962, the Committee for the Light Alloy High Pressure vessels had been established in the Light Metals Society, and carried out investigation of the controlling regulation of high pressure gas as well as of its application regulation standard, method of vessel manufacturing and the inspecting specification of vessels
Writers, members of the committee, carried out such test of 7 litre seamless vessels made of four kinds of light alloy and designed with to safety factors of 4 and 3.
Since the results of these experiments and researches had been reported by Dr. Fukai and its associates of the Sumitomo Light Metals Co., Ltd., here is only mentioned the test result conducted directly by writers.
While the problem of fixing up the design criterion of high pressure vessel, standard of material, and specification of inspection requires a deliberate consideration in order to prevent any injury, it was found that according to the testing and research carried out in the Committee as well as specifications in the countries abroad, coupled with the several practical examples, it appeared that there is no necessity of specifying in its application regulation the tensile strength shall not be less than 37kg/mm², elongation not less than 18% for the mechanical properties of material, and heat the safety factor of about 3 may be allowed.

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