Investigation on the Fatigue Properties of Steel Wire (Part I)

Effect of the reduction by drawing and the low-temperature annealing upon the fatigue strength of high carbon steelwire

Abstract

The effect of low-temperature annealing upon the properties of cold-drawn steel wires has been studied by many investigators, and it has been found that annealing at temperatures up to 400°C after cold-drawing improves their properties to a considerable degree, and the advantage is taken in the steel wire industry. The representative investigation on the effect of low-temperature annealing upon the fatigue properties of carbon steel wire was reported by E.T. Gill and R. Goodacre, and even up to the present, their result has been quoted in many reports and books. They reported that for all the carbon steel wire they examined, there was a critical reduction, at which the fatigue limit of high carbon steel wire under certain annealed state fell considerably below that of the wire as-drawn.
Present investigation was planned for researching the existence of this critical reduction, for 0.65% carbon steel wire, drawn at various reduction, from 60% to 90%, with subsequent annealing in the range 150°C to 400°C, it was investigated that the effect of low-temperature annealing upon the fatigue properties and its tensile properties. The diameter of the specimen was 1.3mm.
The fatigue test was made on the polished specimen using the Hunter fatigue testing machine. As the result of the fatigue test, it was clarified that the fatigue limit of 0.65% carbon steel wire increased as the reduction increased for wires both as-drawn and annealed and so there was not any critical reduction, and that the maximum fatigue limit was found at the annealing temperature 200°-300°C.
From the results obtained by this investigation, it was made clear that the presence of the critical reduction reported by Gill and Goodacre was due to their unpolished specimen.