Study On Friction And Wear Characteristics And Failure Behavior Of Internal Steel Wires Of Mine Hoisting Wire Rope

Because the mine hoisting has the characteristics of large load,high drop and poor operating conditions,the steel wires of hoisting wire rope are easy to produce fretting wear,corrosion wear and fatigue damage,which will lead to the fracture failure of steel wires and seriously affect the service life and safety of hoisting wire rope.Therefore,the research on the friction,wear and failure behavior of steel wires inside mine hoisting wire rope is carried out,so as to reveal the friction and wear characteristics and the fracture failure mechanism of internal steel wires under different contact parameters and environments.The above research results are of great significance to evaluate the service life of hoisting wire rope and ensure the safety of mine hoisting.Firstly,the dynamic model of mine hoisting wire rope was constructed,the dynamic load variation of wire rope during the hoisting process was explored,and the evolution of the contact force,sliding displacement and tensile force between steel wires in multilayer strand rotation-resistant rope with the hoisting quality was analyzed.The results show that compared with the acceleration and deceleration stages,the dynamic load of hoisting wire rope at uniform speed stage decreases most obviously and fluctuates the most.The tension of core wire in the same strand is greater than that of side wire.For the same layer of steel wire in the strand,the tension of core strand wire is the largest,the tension of inner strand wire is the second,and the tension of outer strand wire is the smallest.As the lifting quality increases,the variation range of the tensile force is 73.52 N～508.19 N,the variation range of the sliding displacement is 43.79μm～81.95μm and the variation range of the contact force is 16.15 N～977.34 N.The contact parameters variation law of internal steel wire obtained in this chapter can provide important basic data for the study of friction and wear characteristics between steel wires inside hoisting wire rope.Next,based on the dangerous contact area and contact form between steel wires inside multilayer strand rotation-resistant rope,the friction and wear test rig of steel wires inside hoisting wire rope was designed.The evolution law of the friction and wear characteristics between steel wires with the contact parameters（the contact force,fretting amplitude,cross angle and torsion angle）under different contact forms was explored using the test rig.The influence of wire diameter on the friction and wear characteristics between steel wires was analyzed.The results show that the contact position between the side wire of inner strand and the side wire of outer strand is the dangerous contact area inside hoisting wire rope,the contact forms between steel wires are divided into the convex contact pairs and the concave contact pairs.The friction coefficient between steel wires increases with the increase of the fretting amplitude and torsion angle,respectively,but decreases with increasing the contact force and crossing angle,respectively.In the stable stage,the contact surface of steel wires is in partial sliding state.With the increase of the contact force,the friction coefficient between steel wires decreases to 0.646,and the worn depth and wear coefficient reach 236.18μm and 1.46×10^-7 mm³/（N·mm）,respectively.Compared with the concave contact pairs,the wear between steel wires under the convex contact pairs is more serious.The contact between steel wires with different diameters inside the hoisting wire rope will aggravate the friction and wear,and the friction coefficient and worn depth reach 0.911 and 261.42μm,respectively.The main wear mechanisms of steel wires under dry friction are abrasive wear,adhesive wear and fatigue wear,and the material delamination phenomenon of wear scar surface under concave contact pairs is more serious.Then,through simulating the mine hoisting environment,the effects of grease lubrication,mineral dust,water leaching and corrosion solution on the tribological characteristics between steel wires inside hoisting wire rope were explored.Moreover,the friction and wear mechanisms of steel wires in different contact forms under complex environment were revealed.The results show that the increase of contact force will aggravate the friction force and wear results of steel wires in complex environment,and the wear between steel wires under the convex contact pairs is more serious than that under the concave contact pairs.The wear degree of steel wires lubricated by the original grease is the smallest（the maximum worn depth is 57.23μm）,and the wear of steel wires under acid solution corrosion is the most serious（the maximum worn depth is 138.51μm）.The ore particles reduce the friction coefficient between the wires significantly,but aggravate the wear of steel wires（the maximum worn depth is 104.21μm）,and caused adhesive wear characteristics on the wear scar surface.A large number of corrosion products are distributed on the wear surface in the corrosive environment,and the larger the contact force,the more serious the characteristics of abrasive wear and corrosive wear.Finally,the variation law of steel wire residual strength with worn depth in complex environment was analyzed.Through the fretting fatigue test,the evolution law of steel wire fatigue life under different contact parameters and environment was explored,and the fracture failure mechanisms of steel wires inside hoisting wire rope in complex environment were revealed.The results show that the worn depth of steel wires increases exponentially with increasing the cycles,the worn depth increases the fastest under dry friction,and the worn depth increases the slowest under the grease lubrication.The worn steel wire goes through the elastic deformation,plastic deformation and fracture failure.The residual strength of steel wires lubricated by the original grease is the largest and that under dry friction is the smallest.The tensile fracture failure mechanisms of worn steel wires under acid solution corrosion include ductile fracture and brittle fracture.The fracture surface of steel wires under other environments includes fibrous zone and shear lip.There are fracture notches on both sides of wear scars,and the tensile fracture failure mechanism is mainly ductile fracture.The fatigue life of steel wires decreases with the increase of the contact parameters.The fatigue life of steel wires under dry friction is the smallest,the fatigue life of steel wires under acid solution corrosion is the second,and the fatigue life of steel wires lubricated by the original grease is the largest.The fatigue fractograph of steel wires includes fatigue source region,crack propagation region and final fracture region.A large number of secondary cracks and dimples appear in final fracture region under dry friction,water lubrication and acid solution corrosion,the fatigue fracture failure mechanism of steel wires is mainly ductile fracture,while the fatigue fracture failure mechanism of steel wire under grease lubrication is mainly brittle fracture.