Study On Wear Mechanism And Failure Evaluation Of Herringbone Gate Bottom Friction Pair

As a navigable building,the ship lock is an important part of the entire water conservancy and hydropower project.Today’s water transport industry is developing rapidly,and the normal operation of the ship lock is particularly important.Once the ship lock fails and needs to be repaired,it will cause the waterway where it is located to be severely broken,causing major economic losses and social impact.The herringbone gate is the most commonly used gate form in the ship lock.The bottom pivot is the main load-bearing system of the herringbone gate.The serious wear is the main reason for the ship lock maintenance.Therefore,it is urgent to solve the friction and wear problem of the bottom friction pair of the gravitational gate.In this paper,the friction and wear test method is used to study,and the equivalent wear test is carried out based on the actual research conditions of the bottom pivot as the basis of the test design.The relevant data of the built-in herringbone gates were collected,including the width,height,weight,opening and closing time of the gate,the radius of the low pivot mushroom shaft,the low-end pairing material and lubrication conditions,and the distribution according to the width of the gate.The herringbone gate is classified.The maximum contact stress and relative linear velocity of each type of gate are obtained by empirical formula.The calculation shows that the relative linear velocity is too small,so the influence of contact stress is mainly studied.6 kinds of typical herringbone bottom pivoting subgroup(steel/copper(40Cr/ZCu Al8Mn13Fe3,40Cr/QAL9-4);steel/steel(40Cr/38 Cr Mo Al A,40Cr/45#);steel/nodular cast iron(40Cr/QT700-2,40Cr/QT600-3))Friction and wear tests under different contact stresses under water lubrication and grease lubrication conditions,respectively.The wear test obtained the relationship between the wear amount and the friction coefficient with time under different contact stresses of each sub-group under grease lubrication and water lubrication conditions.The change of wear amount provides the basis for analyzing the wear resistance of the subgroup,and provides the original data for establishing the wear life prediction model.The friction coefficient and the SEM image of the wear surface of the sample provide a basis for exploring the wear mechanism of the friction pair.The results showed that:1)Under low speed and heavy load,the wear of the six sub-groups is positively correlated with the contact stress,that is,the wear amount increases with the contact stress;when the same contact stress,the friction pair Under grease lubrication,it has better wear resistance under water lubrication conditions(except for the 40Cr/ZCu Al8Mn13Fe3 subgroup with contact stress of 19.1-25.0 MPa).2)Under low-speed and heavy load,in the three types of friction pairs,the steel/copper sub-group has the worst wear resistance performance.At lower contact stress(10.6-19.1 MPa),steel/spheroidal ink The wear resistance of cast iron with sub-group is better than that of steel/steel with sub-set,but at higher contact stress(21.1-25.0 MPa),steel/steel with sub-group has better wear resistance.In water lubrication,the steel/steel sub-group is not suitable for water lubrication under low speed and heavy load.The steel/nodular cast iron with sub-group shows the best wear resistance,The steel/copper wear resistance of the copper sub-group is poor.3)Under low-speed and heavy load,the wear mechanism of the six sub-groups is the same when the grease is lubricated.When the actual contact stress of the friction pair is below the allowable stress,the wear mechanism is mainly characterized by abrasive wear;When the actual contact stress of the secondary exceeds the allowable stress,the wear mechanism is a mixed state in which the adhesive wear is dominant and the abrasive wear is accompanied.In the case of water lubrication,for the steel/copper sub-group,the wear mechanism is mainly in the mixed state with abrasive wear and accompanying adhesive wear;for the steel/steel sub-group,the wear mechanism is mainly adhesive wear.For the40Cr/QT700-2 matched subgroup,the wear mechanism is characterized by the increase of the contact stress,which means that the abrasive wear changes to the mixed state with abrasive wear and fatigue wear,and finally becomes adhesive wear;With the increase of contact stress,the wear mechanism of 40Cr/QT600-3 is characterized by fatigue wear to the mixed state with fatigue wear and accompanied by abrasive wear,and finally becomes adhesive wear.4)Based on the grey system theory GM(1,1)model,the wear life prediction model of friction and wear test under single factor condition is established.The model test results show that the model meets the accuracy of the first-order model,and the prediction accuracy of the wear amount reaches 96%,indicating that the GM(1,1)model can be used for the low-speed heavy-duty gate low-shaft friction pair under stable wear conditions.Wear failure evaluation has practical engineering significance.The wear failure evaluation was carried out by the GM(1,1)model.It is considered that 40Cr/QT700-2 is the best choice for sub-selection when the contact stress range is 10.6-15.9 MPa under greaselubrication conditions;when the contact stress exceeds 19.1 MPa 40Cr/38 Cr Mo Al A is the best choice for the secondary.Under water lubrication conditions,the contact stress range is 10.6-25.0 MPa,and 40Cr/QT600-3 is the best choice.