著者

上田 太郎 朝倉 健二

出版者

公益社団法人 日本材料学会

雑誌

材料試験 (ISSN:03727971)

巻号頁・発行日

vol.9, no.78, pp.192-199, 1960

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This investigation was planned for researching the effect of the repeated stress upon the longitudinal residual stress existing in the cold drawn carbon steel wire. For the specimen, 0.65% carbon steel wires drawn with 60% and 80% reductions were used, and the diameter of these wires was 1.3mm.<BR>For the measurement of the longitudinal residual stresses existing in these fine steel wires, the present writers adopted the mechanical method and electro-magnetic method.<BR>Hunter fatigue testing machine was used in this investigation, and from S-N curves of these wires the fatigue limit stress and three stresses over the fatigue limit were chosen as the repeated stress to research the behavior of residual stress. The fatigue test specimens were taken out from the fatigue testing machine at 10<SUP>7</SUP> and 10<SUP>6</SUP> cycles for the fatigue limit stress and at the number of cycle just before the break down cycle for each stress over the fatigue limit, and then the specimens for measurement of residual stress were cut out from the middle part of these fatigue test specimens. The distributions of longitudinal residual stresses of these specimens subjected to the repeated stresses were measured and those were compared with that of the standard specimen not subjected to the repeated stress.<BR>From the results obtained by this investigation, it was made clear that if the longitudinal tensile residual stress existing in the outer part of the wire was about 20-30kg/mm<SUP>2</SUP>, the distribution of longitudinal residual stress of the cold drawn steel wire was little affected by the repeated stress under rotating bending over the fatigue limit, and that which is equal to the fatigue limit, either.