Tribo-fatigue behaviors of steel wires under coupled tension-torsion in different environmental media

Abstract

Tribo-fatigue behaviors of carbon structural steel wires under coupled tension-torsion in the tests with different tribo-fatigue parameters in different environmental media were investigated in the present study. The coefficient of friction was recorded by the self-made test rig. The wear depth profile was measured using three-dimensional white light interferometer. Morphologies of the wear scar and fracture of steel wire were observed employing the scanning electron microscope. The electrochemical analyzer was used to investigate electrochemical corrosion characteristics of steel wire. The crack propagation of steel wire was explored employing the X-ray computed tomography. The results show that coefficients of friction in different environmental media decreases by the order: air, alkaline and neutral electrolyte solutions, deionized water and acid electrolyte solution. The decrease order of maximum wear depth and increase order of fatigue life are as follows: air, acid, neutral and alkaline electrolyte solutions, and deionized water. Wear mechanisms include abrasive wear, adhesive wear, corrosion wear, fatigue wear in cases of different environmental media. The degree of electrochemical corrosion and maximum crack depth of fatigue wire are the largest in the acid electrolyte solution. The fracture is divided into zones of crack initiation, crack propagation and final fracture. Increases of tribo-fatigue parameters cause overall decreases in the coefficient of friction, degree of electrochemical corrosion and fatigue life, and increases in the maximum wear depth, crack propagation rate and surface damage.