Effect of Fretting Frequency on Tension-Torsion Fretting Corrosion Fatigue Behavior of Steel Wire

Tension-torsion fretting corrosion fatigue is one of main failure modes of hoisting rope in the deep coal mine. The vibration frequency of hoisting rope in the deep coal mine determines the fretting frequency between steel wires, directly affects the tension-torsion fretting corrosion fatigue mechanism and damage degree of steel wire, and thereby restricts the service safety of hoisting rope in the deep coal mine. In the present study, the self-made tension-torsion fretting corrosion fatigue testing rig was employed to conduct tension-torsion fretting corrosion fatigue tests of steel wires in the acid electrolyte solution. Hysteresis loops of tangential force versus displacement amplitude and torque versus torsion angle of steel wires were established to analyze the contact status between steel wires and dissipated energies along axial and torsional directions during tension-torsion fretting corrosion fatigue. The scanning electron microscope and three-dimensional white-light interferometer for surface topography were employed to investigate wear scar morphologies and evolution characteristics of wear depth profile of steel wires during tension-torsion fretting corrosion fatigue. The X-ray three-dimensional imaging system was employed to reveal tension-torsion fretting corrosion fatigue crack propagation evolution laws of steel wires. The Tafel polarization curves and impedance spectra of steel wires after tension-torsion fretting corrosion fatigue tests were analyzed by the electrochemical analyzer in order to explore the electrochemical corrosion tendency and corrosion resistance of steel wires. Meanwhile, the influence laws of fretting frequency on contact statuses between steel wires, dissipation energies of steel wire along axial and torsional directions, fretting wear mechanisms of steel wire, fatigue crack propagation evolutions and fatigue lives of steel wires, electrochemical corrosion tendency and corrosion resistance characteristics of steel wires were revealed. The results showed that the contact status between steel wires varied from the mixed states of gross slip and partial slip to the gross slip state during tension-torsion fretting corrosion fatigue with increasing fretting frequency. The hysteresis phenomenon of torque versus torsion angle of steel wire weakened with increasing frequency. An increase of frequency causes overall decreased in dissipation energies corresponding to hysteresis loops of tangential force versus displacement amplitude and torque versus torsion angle of steel wire. The coefficient of friction between steel wires and the wear depth of steel wire both decreased with increasing fretting frequency. Wear mechanisms of steel wires were abrasive wear, adhesive wear, fatigue wear and corrosion wear in cases of all frequencies. An increase of fretting frequency causes decreased in the maximum crack depth and crack propagation rate of steel wire and an increase in the fatigue life of steel wire. The electrochemical corrosion tendency of steel wire decreased and the corrosion resistance of steel wire increased with increasing fretting frequency.