For the synopsis of this work see the Report I. [This journal 2 (1938), 247]

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Physical and mechanical characteristics of brass coating sprayed with an electrically operated pistol under various conditions were studied. The arc-voltage and the pressure of air blast in the spraying were found to have a marked influence on the composition of the coating, that is, the content of Cu in the coating increased with increasing voltage and pressure, in spite of the fact that it is almost independent of the condition of spraying with a gas pistol. The microstructure of the coating was very complicated owing to the presence of oxides, eutectics, etc. The coefficient of thermal expansion of the brass between 20° and 70° was nearly 10% smaller than the normal brass of the same composition. A small irregular contraction at about 340° which is due to the recrystallization was also observed during the heating. The apparent specific gravity was nearly 15% smaller than the real value, while the electric resistance was 2.64-3.78 times larger than the normal brass, indicating that the coating is porous and rich in oxides. The hardness depended markedly upon the pressure of air blast. The tensile strength, elongation and the impact value were quite small, owing to the brittleness of the coating. The adhesive strength of the coating sprayed on the soft steel depended much on the degree of roughness of the steel surface.

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It is well known that the internal stress in aluminium alloys is due to cold working. From the inference that the weakening of grain boundaries of the alloy in which remains the internal stress, causes cracking just in the same way as the season-cracking of copper-alloy, the author performed this research.
In detecting grain boundaries of aluminium-alloys, the salts of mercury seem suitable and as mercurous nitrates do not act to aluminium-alloy, a saturated solution of mercuric chloride was tested. But by another experiment it is found that the addition of 1/15 N HO to that solution gives still more satisfactory result. By this solution, some of the cold drawn duralumin, super duralumin and aluminium-alloy containing Zn 8%, Mg 1.5% and Cu 2% cracked in a few seconds.
The internal stress in these alloys caused by a working ratio was studied and it was found that a stress of 10kg/mm² or more in hollow sunk duralumin tubes could be easily detected by this solution. By annealing the duralumin tubes having 20kg/mm² stress at various temperatures and durations, it was found that at an annealing temperature of 275_??_300° the solution indicated the removal of stress to a great extent. Drawn super duralumin and aluminium-alloy bar containing Zn did not also show cracks by annealing at 275° and 250° respectively. According to Rosenhain the season crack in an E-alloy containing Zn could be prevented by adding 0.5% of Mn to it. In order to prevent the season crack of an alloy containing Zn 8%, Mg 1.5% and Cu 2% the author added to it a small quantity of Mn, Mo and Cr, but made little s_??_ccess.

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The structural Ni-Cr steel, which has been quenched and tempered, takes various forms of stress-strain diagram at the yield point. In this investigation the effect of heat treatment (such as tempering temperature, tempering time, cooling velocity from tempering temperature, double-quenching, quenching velocity) on the form of stress-strain diagram of some special steels was studied. To measure the elongation in the tensile test Martens-Mirror-Extensometer has been used. The kinds of special steels used in the test were low Ni-Cr steel, 3% Ni-Cr steel, Ni-Cr-Mo steel, Cr-Mo steel and carbon steel.
The result of the test may be summarized as follows:
(1) The forms of stress-strain diagram of Low Ni-Cr steel and 3% Ni-Cr steel was just the same as that of low carbon steel, when test pieces were tempered at about 70° below the Ac₁ point; however, the yielding phenomenon disappeared, when the tempering treatment was conducted at about 20° below the Ac₁ point. The disappe-aring phenomenon of yield point was even more noticeable as the Ni content of the steel increased, and the same aring phenomenon of yield point was even more noticeable as the Ni conten of the steel increased, and the same phenomenon took place even at a lower tempering temperature as the carbon content increased.
The length of time in which the test piece was held at tempering temperature, and its cooling velocity from the tempering temperature have had almost no effect on the form of stress-strain diagram.
(2) The yield point and yielding phenomenon of Ni-Cr-Mo steel and Cr-Mo steel did not diminish, even when the tempering treatment was conducted at a temperature just below the Ac₁ point. It is deduced therefore that Molybdenum acts to prevent the diminution of the yield point.
(3) In the case of carbon steel, the yield point, did not diminish, even. when test pieces were tempered at a temperature just below the Act point.
(4) The low Ni-Cr steel which has been double quenched and tempered is generaly believed to have no yielding phenomenon at the yield point, but it is ascertained that the low Ni-Cr steel shows a typical yielding phenomenon.
(5) Mildly quenched Ni-Cr and low Ni-Cr steel did not show the yielding phenomenon even when tempered at such a temperature, as may readily shows the yield point in the case of severely quenched test piece.

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In connection with Be-Cu alloys containing about 2.2% of Be a number of investigations have already been carried out, but, the results of these investigations are quite at variance. In this research several quenched specimens of the same alloys prepared under various conditions were studied, by measuring the changes in differential dilatation, hardness, microscopic structure and crystalline configulation, which take place in these specimens during tempering.
The aspects of these changes indicated to vary according to the difference in the procedure of casting, working and annealing, to which specimens had previously been subjected, the variation being most noticeable with some of the specimens in their dilatometric change. It is confirmed that the aspect of these changes of the former investigations was essentially the same as one of those found in the present experiment, and that the discrepancy among the results formerly obtained by the different investigators, is chiefly attributed to the historv of the specimens.

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