Abstract

Currently, retreading for extending the life of tires has been discussed to reduce the environmental impact. Therefore, obtaining very high cycle fatigue properties of steel wires used to reinforce radial tires are required. In this study, the very high cycle fatigue properties of solid fine wires of eutectoid steels were obtained for the fundamental understanding of the fatigue mechanism. Solid fine wires of 0.3 mm in diameter produced by the blast furnace and the electric arc furnace were prepared with the same Young's modulus and tensile strength. A method to prepare dumbbell-shaped specimens from solid fine wires was developed by using electropolishing to prevent fatigue failure at an edge of the grips. In the method, the cathode was formed into a circle shape, and an anode, i.e. a specimen, was placed so that it passed through the center of the cathode circle. Then, fatigue tests under axial loading were conducted using an electromagnetic fatigue testing machine. The stress ratio was set to 0.1 and the cyclic frequency was set to 200 Hz. The results showed that the fatigue limits were about 600 MPa for both materials and the influence of steel production process on the fatigue limit was not found.