Study On The Bonding Mechanism And Experiment Of The Interface Of New Composite Structure Bushing

Oil film bearing is widely used in the key equipments of iron and steel,mine,metallurgy,electric power and so on because of its advantages of low friction coefficient,low loss and high rigidity.Bushing is the core part of oil film bearing,its structure and stress during operation play an important role in the final performance of oil film bearing.At the present stage,the oil film bearing bushing adopts the combination of steel body and Babbitt alloy.In recent years,the new multilayer structure bearing bushing is developed.The interfacial bonding performance between the layers of the oil film bearing bushing is related to the final performance of the rolling mill oil film bearing.It affects the safety and reliability of the production line.The study of multilayer alloy composite structure bushing has become an important direction of oil film bearing technology improvement and a key component of the core components of high-end equipment manufacturing industry in China.It is very important for the structure and performance of the equipment to study the interfacial bonding strength of a new type of oil film bearing multi-layer structure bushing.Firstly,according to the test operation standard,the bimetallic bonding strength specimen of the bearing was designed and prepared under the welding process.The SEM test was carried out on the specimen while the microstructure of the bonding interface,the distribution of the crystal system and the phase analysis of the specimen were analyzed.The bonding mechanism of Babbitt alloy with different grades of steel in welding process was investigated.The residual stress distribution on the surface of different steel bodies combined with Babbitt alloy was measured by XRD residual stress tester,and the best substrate material for bearing bushing was judged.Secondly,taking a new type of compound structure bushing Babbitt alloy ZCh Sn Sb8-4 as the research object,on the basis of the modeling characteristics of atomic substitution method,the proportion of three components of Cu₆Sn₅,Sn Sb,Sn in the Babbitt alloy is considered.The interfacial bonding properties of multilayer alloy composite bushing were simulated and analyzed by molecular dynamics method,and the energy of each layer of three and five layers of composite bushing was calculated under the same conditions.The bonding energy between the adjacent alloy interfaces was calculated and analyzed,the dangerous bonding interface was judged,and the method of judging the dangerous bonding interface of composite materials was given.The results show that the minimum interfacial bonding energy of the five-layer composite bushing is greater than the minimum interfacial bonding energy of the three-layer composite bushing.That is the interfacial bonding performance of five-layer composite structure bushing is better than that of three-layer composite structure bushing.At the same time,according to the bonding energy of the adjacent two interfaces of different structure bushing,it is found that the dangerous bonding interface may be caused by different composite layer bushing.The interfacial bonding energy between the steel and lead alloy layer and the nickel gate layer is the largest and the bond is the strongest,and the interface bonding energy between the nickel gate layer and the Babbitt alloy layer is the least,and the phenomenon of alloy falling off is the most likely.A novel composite structure was studied at the molecular level.The bonding mechanism of the bushing interface provides a reference for the production practice.Finally,the complete formula of the singular stress field at the interface end of composite material is derived.The singular stress field at the interface end of ZSnSb11Cu6/20 steel and ZSnSb11Cu6/FeSn₂/20 steel model is calculated by calculating the Dundurs parameters of the singular stress field at the interface of composite material and its related parameters.The magnitude and distribution of principal stress and shear stress near the interface end are compared to judge the dangerous bonding interface.The results show that the singular stress of Babbitt alloy combined with FeSn₂is smaller than that of other steel materials,and the interlayer material FeSn₂can reduce the singularity stress between Babbitt alloy and steel body.In the ZSnSb11Cu6/FeSn₂/20 steel three-layer structure bushing model,the singular stress at the ZSnSb11Cu6/FeSn₂interface is greater than the singular stress at the FeSn₂/20 steel,so the bonding performance of the FeSn₂/20 steel interface is better than that of the ZSnSb11Cu6/FeSn₂interface.ZSnSb11Cu6/FeSn₂ is a dangerous interface.