Annealed 1050 and 5052 alloys were cold rolled at a low velocity 20m/min and at reduction 30, 50 and 70% using soluble rolling oils. Effects of the particle size distribution of emulsion and the composition of the rolling oil on lubricity were examined. Addition of a surfactant was also examined. The particle size distribution of emulsion is controllable by adding the surfactant. The water soluble cold rolling oils have better lubricity than conventional oily rolling oils.

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Circular grooves to retain lubricants were worked on the surface of columns of 5056BD-0 aluminum alloy. The lubricating ability of the circular grooves and various lubricants were estimated by measuring barreling forms of the swaged columns. One groove ensures good lubrication. The width of the grooves has little effect on lubrication. The groove depth 0.4mm is sufficient. Lubricants have remarkably different lubricating abilities respectively. Graphite, MoS₂ and synthetic wax well lubricate. The depth and the total volume of circular grooves change in swaging at compressibility up to about 20%. The outflow of lubricant occurs at the compressibility up to 20%.

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Cylindrical ingots of 12 different casting and die casting alloys were cast under ambient and 2000kgf/cm² pressures. The specific gravity, proof and tensile strengths, elongation and impact value of high pressure castings are improved to different degrees corresponding to the casting characteristics of the alloys. The alloys having wider solidification temperature ranges and intensified tendencies to hot shortness show higher relative increase in mechanical properties more significant. The effect of high pressure casting is more pronounced for the alloy having poor castability in such casting indices as hot shortness and pressure tightness that are related to occurance of macroscopic casting defects. Based on the above correlation a new castability criterion including mechanical properties of castings is proposed by evaluating the effect of high pressure casting. The alloys suitable for high pressure casting is discussed based on the present experimental vesults.

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An attempt to evaluate the fracture toughness of 5083 and 7075 alloys is made by observing the stretched zone (SZ) formed ahead of pre-crack in a Charpy test. The width and height of the stretched zone (SZW and SZH) analyzed stereographically from fracture toughness. Twice SZH corresponds to the critical crack tip opening displacement (CTOD_c). The plane strain fracture sunface. (K_1c) estimated from CTOD_c measured is in good agreement with the valid K_1c already informed. The fracture toughness is sufficiently appreciable by measuring SZ even in small size test pieces. A proportional relation is found between SZW and SZH. Plastic blunting of crack tip advances up to 60 to 70° in a particular direction.

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Tensile tests at high temperatures were carried out for Al-Si alloys containing Si 1.7 to 13.7% solidified under high pressures up to 2000kgf/cm². The effect of high pressure on the tensile strength intensifies with increasing Si content, but moderates with temperatures and almost disappears at 400°C. The effect of high pressure on the total elongation is noticeable for low Si content alloys and moderates with increasing Si content. The effect is kept even at 400°C to some extent. The tensile strength increases with the strain rate at high temperatures, although it scarcely depends on the strain rate at room temperature. The maximum of total elongation for the most part appears at the strain rate approximately 10^-3s^-1.

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A role of CO₂ in suppresing oxidation of molten Al-Mg alloys in air-CO₂ atmosphere was studied. The surface film on the molten Al-Mg alloys in air-CO₂ atmosphere is composed of MgO with a slight amount of carbon. Carbon does not form carbon compounds such as MgCO₃. CO₂ functions more effectively for the molten metal on which a thick MgO film covers, but does ineffectively for the molten metal on which thin MgO and/or MgAl₂O₄ films cover. The protecting ability of surface film depends on the concentration of CO₂ at the film forming period, but does not on the gas applying time in the period. This phenomenon is attributed to prevention of O₂ diffusion into the molten metal by the MgO film which adsorbs CO₂ gas.

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