Assessment of shear fatigue property of rolling contact metal material and estimation of fatigue limit maximum contact pressure using same assessment

摘要

A method of assessing the shear fatigue property of a metallic material that undergoes a rolling contact includes a testing step for determining the relation between the shear stress amplitude of a rolling contact metallic material and the number of loading by means of an ultrasonic torsional fatigue test, and a shear fatigue strength determining step for determining the shear fatigue strength τlim within the ultra long life regime from the relation between the shear stress amplitude and the number of loadings, which relation has been determined during the test step, in accordance with a predetermined standard. It is a completely reversed torsional fatigue test, in which torsional vibrations, respective torsions in the positive rotational direction and reversed rotational direction of which are symmetrical relative to each other, are applied to a test piece.

主权项

1. A method of assessing a shear fatigue property of a metallic material that undergoes a rolling contact using a torsional vibration converter for generating torsional vibrations, which will become positive and reversed rotations about the axis of rotation when an electric alternating power is applied, an amplitude amplifying horn having a tip end, provided with a mounting portion to which a metallic material is fitted coaxially and also having a base end that is fixed to the torsional vibration converter, and operable to amplify the amplitude of the torsional vibration of the vibration converter applied to the base end, an oscillator, an amplifier for amplifying an output of the oscillator and then applying the output to the torsional vibration converter, and a control unit for applying an input of the control to the amplifier, which method comprises:
a testing step of determining a relation between a shear stress amplitude of the metallic material and the number of loadings by means of an ultrasonic torsional fatigue test; and a shear fatigue strength determining step of determining a shear fatigue strength τlim within an ultra long life regime from the determined relation between the shear stress amplitude and the number of loadings in accordance with a predetermined standard.