Research On Crack Growth Evolution And Electrochemical Corrosion Behavior Of Tensile And Torsional Composite Fretting Fatigue Of Mining Steel Wire In Acidic Solution

More than 60% of mine water in northern China is acidic electrolyte solution.During the process of mine hoisting,the hoisting wire rope bears cyclic tensile,bending and torsional loads as well as the drenching effect of acidic electrolyte solution,which leads to the combined fretting fatigue of steel wire in acidic solution,i.e.fretting wear,fatigue crack propagation and electrochemical corrosion,resulting in cross-section loss and wire breakage of steel wire,eventually leading to the failure and fracture of steel wire rope,causing the malignant tank falling accident of well destruction and death.Therefore,it is of great significance to carry out research on the growth and evolution of fatigue cracks and electrochemical corrosion behavior of steel wire for mining in acidic solution for prolonging the service life of steel wire rope and ensuring the safety and reliability of mine hoisting.In this paper,the friction and wear characteristics(hysteresis loop,friction coefficient,wear depth and surface micro-wear morphology)of steel wire in different tension-torsion composite fretting fatigue parameters(contact load,torsion angle,loading frequency,stress ratio and stress amplitude)are obtained through a self-made steel wire tension-torsion composite fretting corrosion fatigue device,and the fatigue crack propagation characteristics(crack profile,propagation depth and propagation rate)of steel wire under different tension-torsion composite fretting fatigue parameters are investigated.Combined with electrochemical analyzer,the influence of different fretting parameters on electrochemical corrosion characteristics(polarization curve,impedance spectrum,etc.)of steel wire in acidic solution was discussed.The wear,fatigue and electrochemical interaction mechanism of steel wire are analyzed,and the life prediction model of steel wire in acidic solution is established.The results show that the increase of contact load,torsion angle,stress amplitude and the decrease of loading frequency aggravate the fretting wear and crack growth rate of steel wire,and reduce the corrosion resistance of steel wire.The increase of stress ratio increases fretting wear depth and crack growth rate,and reduces electrochemical corrosion effect of steel wire.With the increase of fatigue times,the depth of crack propagation increases,and the crack morphology gradually changes from elliptical or irregular arc shape to linear shape.In different tension-torsion composite fatigue fretting parameters,the fatigue life of steel wire shows a power exponential relationship,and the life prediction model is in good agreement with the results.The order of importance of different tension-torsion composite fatigue fretting parameters to the fatigue life of steel wire is as follows: stress amplitude > stress ratio > loading frequency > contact load > torsion angle.