When a cold drawn mild or hard steel wire is aluminum coated by hot-dip process, the tensile strength decreases to between 50 and 60% of the original tensile strength.
Hereby, we applied hot-dip Al-coating on any cold drawn mild (0.1%C) and hard (0.6%C) steel wire by passing them through molten commercial pure Al, Al-0.2% Be and Al-0.2% Be-5% Si bath respectively, and then attempted to revive the tensile strength of these aluminized steel wires by cold drawing. At the same time, we investigated the change of other mechanical properties and corrosion resistance by cold drawing.
Both the aluminized mild and hard steel wire by passing through the molten Al-Be or Al-Be-Si bath show comparatively quicker revivification of the tensile strength by cold drawing process than the aluminized steel wire by passing through molten commercial pure aluminum bath.
When a cold drawn mild steel wire (0.1%C) is applied with hot-dip aluminum coating, it is possible to revive up to nearly the original tensile strength before coating by after cold drawing of about 70% total reduction.
When any cold drawn hard steel wires (0.6%C) are applied to hot-dip aluminum coating by passing them through molten commercial Al or Al-Be-Si bath, they can be cold drawn to 40% and 60% total reduction respectively, and then it is possible to revive up to about 70% and between 80 and 95% of the original tensile strength before coating respectively. Beyond these reduction, the torsion and wrapping tests on these after cold drawn aluminized steel wires show worse result, so these over drawn steel wires become impossible to be used as wires for any purposes.
The corrosion resistance of these cold drawn aluminized steel wires become worse proportionally to the increase of the reduction of cold drawing, accordingly to the decrease of the thickness of coated layer.
Generally, the steel wire applied to Al-coating by passing it through molten Al-Be-Si bath can be cold drawn without cracking of coated layer and shows much superior corrosion resistance than the steel wires coated by the other two simpler molten metal bathes.

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It is badly needed to find out appropriate catalysts for the generation of endthermic gas for carburizing from commercial propane or butane gas, because, in Japan, our commercial propane and butane usually contain various amounts of unsaturated and heavy hydrocarbon; which deleriorate the catalytic action due to free carbon deposition on the catalysts.
Therefore, the author studied the function of various pure metallic oxides as the carrier of catalyst and could find that pure Cr₂O₃, CaO and Al₂O₃ were suitable for the purpose, but SiO₂, MgO and Fe₂O₃ not. Further, it was recognized that the oxides impregnated with nickel up to about 5% by weight improved their catalytic action, and the catalytic effectiveness of the impregnated with cobalt was less than that of the impregnated with nickel. The oxides impregnated with cobalt, however, were not so effective as those with nickel.

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By photometric method of analysis, the author determined the chemical composition of the coating with reference to its contained chloride by adding 3N-HNO₃ as oxidizing agent for Fe^.. to the stripping solution of 3N-H₂SO₄, changing Cl′ in the solution into hydrosol of AgCl with 0.1% AgNO₃.
The results obtained were as follows:
(1) Cl-content in the coating produced by Dry Golvanizing Method of washing with hot flux solution such as 5N-NH₄Cl or 5N-ZnCl₂·NH₄Cl was about 0.01% by weight and with 5N-ZnCl₂ was about 0.03%.
Conditions of this experiment were as follows:
Material used was 0.6C steel wire, composition of bath electrolytic zinc, temperature of Zinc bath 450°C, and dipping time 1-2min; hand dipping process being used.
(2) When produced by washing with cold flux solution such as 5N-HCl, 5N-NH₄Cl or 5^N-ZnCl₂, Cl-content was 0.08-0.10%.
Conditions of this experiment were as follows:
Material used was black heart malleable iron, and other conditions were the same as the above.
(3) Cl-content in the coating produced by Wet Galvanizing Method, of using machine and washing with Pb-Zn bath was also 0.01-0.10%. The longer the dipping time in Pb-bath was the less was the Cl-content in the coating.
Conditions of this experiment were as follows:
Specimens used in these experiments were the product of certain factories. Material used was 0.1C sheet, composition of Zinc bath, spelter with 0.1-0.2% Sn and 0.1% Sb, temperature of Zinc bath 450°C±10°C, temperature of Pb-bath 480°C, and dipping time in Pb-bath 7-18sec.

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It is most important to control and check thickness of film painted on the actual structure, for which several methods of measuring paint film thickness were studied.
The result was as follows:
(1) The most satisfactory instrument for this purpose is Elcometer, which works on magnetic principles. It can measure thickness of film with accuracy of about 10per cent.
(2) Surface roughness under the paint film, however, has much to do with the reading of data. Hence, the thickness of prime on second coat cannot be measured accurately, but that of the coat painted over three times can be measured satisfactorily.
(3) Results of the trial on some actual ship's hulls showed reliable values of paint film thickness comparable to microscopic observation of the film, especially on newly built vessels.

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The coloration of high purity Al-Fe, Al-Si and Al-Fe-Si alloys by boiling water were examined.
In well-water, every alloys show the blackening of dark gray or grayish black. And then, as increasing the amounts of alloying elements, their color was tinged with blue or purple slightly. However, the relationships between the surface color and the sort or amount of alloying element could not be found.
In general, low silicon aluminum alloy shows slightly light color compared with low iron aluminum alloy, but in higher silicon alloy (>0.5%), the differences in the degree of blackening are little.
By an addition of potassium silicate or sodium silicate to boiling distilled water, aluminum alloys were darkened fairly. And then, the co-existence of these silicates with carbonate or bicarbonate induced a slight increase in the degree of darkening.

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