Recently, an unknown type of fracturing sometimes occurred to the plastic sheathed hard-drawn stranded copper conductor of the overhead cable that had been used for several years. The present paper describes the assumed cause and the confirmed mechanism of this fracturing. Copper wires in the conductor fractured, without necking down, into pieces of several centimeters in some cases. The cracking initiated at the wire surface on which the maximum tensile stress was applied. The wires were found to have been wet and immersed in corrosive rain water which penetrated into the strand through cable joints. It is likely that this type of fracturing of the conductor belongs to the stress corrosion cracking of copper wires. The hard-drawn copper strand experimentally subjected to the corrosive atmosphere of moist vapor of sulfuric acid under a tensile stress was found to fracture in the same manner as that of the strands practically used.

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Aluminum alloy anodes may be used for cathodic protection of stainless steel in chloride solution. The galvanic interaction between Al-Mn alloys, Al-Mg alloys, Al-Ca alloys and stainless steel has been studied in aerated 0.5N NaCl solution at 40°C by measuring the weight loss and monitoring the galvanic current with a zero impedance ammeter in 140 hours test. The values of the galvanic current density corresponded to the dissolution rates due to galvanic coupling. Galvanic corrosion of Al alloys coupled to stainless steel decreased in the order Al-5%Mg>Al-5%Ca>99.98%Al>Al-1%Mg>Al-1%Ca>Al-1%Mn>Al-5%Mn. Results of the galvanic anode test showed that the galvanic efficiency of Al-1%Mn and Al-1%Ca was higher than that of the other Al alloys. Galvanic current and galvanic potential of Al alloys coupled to stainless steel could be estimated by overlapping the polarization curves. It was shown that the dissolution rate of the anode was proportional to the area ratio (A^C/A^A) of anode and cathode.

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In our previous works it was found that a high C (ca. 0.2%)-low P steel shows an excellent corrosion resistance against pure molten zinc. In this paper a study was carried out on its corrosion behavior in liquid zinc containing 0.15-0.30% aluminum at 440-480°C in comparison with a low C steel. The creep rupture strength of the steels in pure molten zinc at 500°C was measured to evaluate the resistance against deformation due to the gravity of zinc fluid in practical galvanizing pots. After 24hr immersion Γ, δ_1c, δ_1p and ξ alloys were found to form on the surface of all specimens tested under various conditions in accordance with the ternary iron-zinc-aluminum phase diagram. The presence of aluminum accelerates the attack of steel by molten zinc by preventing ξ alloy from forming a continuous protective film. Precipitated carbides assisted a non-porous surface layer of δ_1p alloy in growing thick, and the corrosion of 0.19 C-low P steel was less than that of low C steel. Alloying elements such as C, Mn, Mo, and V, which are known to improve the creep strength in air, also increased the creep strength in molten zinc. Zinc attacks steels not only in the form of uniform corrosion but also in the form of grain boundary corrosion decreasing the effective cross section of steel construction. Consequently, when the same tensile stress is applied, the creep rupture time of steel is shorter in zinc than in air. Zinc permeates deeper into low C steel than into high C steel. All these factors cause the high C steel to possess a higher creep rupture strength than the low C steel. From the observations mentioned above it may be concluded that the high C (ca. 0.2%)-low P steel is one of the most suitable materials which can be used for hot dip galvanizing pots.

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The pitting potential for stainless steels and typical corrosion resistant alloys was determined in deaerated 0.1M NaCl solution at 280°C using an external reference electrode. The 25Cr-5Ni-2Mo and Type 316 showed the highest pitting potential in the series of the alloys. Molybdenum seems to improve pitting resistance at high temperature as well as ambient temperature. It was found that the relative pitting resistance of these alloys at 280°C was almost similar to that of 31°C.

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