Study On The Frictional Wear Characteristics And Residual Strength Of Steel Wire Ropes

Wear is one of the prime reasons for the wire rope degradation,which severely threatens the safety use of wire rope.With the exploitation of deep resources,multi-layer winding of the wire rope has been wildely used under different complex and harsh environments,which results in its premature failure caused by wear and corrosion,then leads to great waste of the wire rope.Therefore,studing on the friction and wear characteristics of the wire rope,revealing its residual mechanical strength and fracture failure mechanism can provide basic data and theoretical support for reducing the wear,ensuring the safety use,increasing the operation rate and extending the service life of the wire rope.The 6×19+FC wire rope was selected as the research object,the friction and wear experiments of the wire rope under different velocities,strokes,contact loads and sliding distances were carried out using a self-made test rig.The friction and wear characteristics of the wire rope under the condition of lubrication failure were revealed.The test results show that the coefficient of friction increases first then decreases with the increase of sliding velocity.The coefficient of friction decreases with the stroke.The temperature rise increases with the velocity and contact load.The surface wear characteristics are furrow,pit,spalling and plastic deformation.The major wear mechanisms are adhesive wear and abrasive wear.With the increase of sliding distances,the wear parameters increase constantly and grow faster and faster.Based on the complex structure of the wire rope,the contact forms between ropes were analyzed.The effects of different crossing angle,cross direction and contact position on the trobological properties and wear distribution of the wire rope were explored.The results show that the coefficient of friction reduces seriously under left cross contact(the strand lay direction and the cross direction are opposite)when the crossing angle is small(7o ~ 28o).As the crossing angle is large(40o ~ 80o),the coefficient of friction discreases more seriously under right cross contact(the strand lay direction and the cross direction are the same),from 0.82 to 0.64.With the contact position moves from the rope strand peak to valley,the wear scar of the rope changes from concentrate on one strand to evenly distribute on two adjacent strands.The friction and wear properties of the wire rope under different corrosions(water,seawater and sulfuric acid)and oils(IRIS-400 M and IRIS-550 A wire rope oils)were explored through surface lubrication and corrosion treatment.The results show that the effect of temperature and rotate speed on the anti-wear properties of the wire rope oils is obvious.With the increase of sliding distance,the coefficient of friction grows fastest and the surface wear is the most severe when the wire ropes subjected to sulfuric acid corrosion,the maximum wear depth is approximately 0.94 mm.When the wire rope slides under lubrication condition,the coefficient of friction is very small(about 0.2),and the temperature rise is less than 7 ?.Corrosion solution can cause degradation of the anti-friction and anti-wear of the wire rope oil,which results in the increase of the coefficient of friction and temperature rise.Moreover,the surface wear will become more severe.The sulfuric acid solution is the most harmful for the performance degradation of the wire rope,followed by seawater and the fresh water is the least harmful.Based on the breaking tensile test of the wear-out wire rope and the ABAQUS finite element simulation analysis,the effects of the wear scar and the degree of wear on the stress characteristics and fracture failure mechanism of wire ropes were explored.The results show that there will be structure deformation,elastic deformation,plastic deformation and fracture failure of the wire rope during the tensile test.The surface wear mainly affects the plastic deformation process and fracture failure behavior.Additionally,the high temperature concentration in the wear scar region is very obvious before the rope fractures.When the crossing angle is large,the residual strength is much lower as the wear scar on the wire rope is caused by left cross contact.When the wear scar concentracts on one rope strand,the effects of the wear depth on the residual mechanical strength of the wire rope are more obvious than that of the wear area.Moreover,the breaking force of the rope will be greatly reduced by broken wire cause by wear.Corrosion will result in the strength reduction of the rope and the sulfuric acid is the most harmful,followed by seawater and fresh water is the least.The effect of wear on the residual bearing capacity of the wire rope with sulfuric acid corrosion is the most obvious.The wire rope breaks at the wear scar position and the ends of the wires without wear show obvious cup and cone shape under tensile load.The fracture mechanism of the wear-out wire rope is mainly ductile fracture and the crack first appears in the region with the maximum wear depth.In the wear scar region,there is stress concentration and unevenly distributed phenomenon under tensile load.