純銅線の回転曲げ疲労における硬さ変化について

概要

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It is well known that the fatigue limit exactly. Accordingly, when the fatigue resistance of those kinds of metals is investigated, the study on the variation tendency of several kinds of their characters which is to be appeared in the course of fatigue test may be considered important from the practical point of view, in addition to that of S-N diagrams. Rotating bending fatigue test was carried out, using nine kinds of pure copper wire of 1 m/m in diameter with a purity of 99・99 % whose value of reduction factor lies from 17・4% to 96・0%, and we investigated about how the hardness value is changed after the fatigue test by factors of variation such as the reduction factor due to cold working, the outer surface or interior of the wire, the repeated stress and thee aging effect, by means of design of experiment, consequently,the following has been obtained : The cold worked pure copper wire may be softened even if it is left at room temperatures, that is the lowering in hardness value gets the smaller, the larger the reduction factor, the repeated stress and the hardness on the surface of the wire are , and this suddenly drop to values smaller than those of interior, so the following has been recognized from the above-mentioned facts that the softening effect of the wire itself would play an important role in the phenomena of fatigue fracture of the cold worked copper wire.
社団法人日本材料学会の論文
1960-07-15