Research On The Mechanism Of Interfacial Damage And Bonding Properties Of Babbitt Alloy/steel

Because the oil film bearing has the advantages of stable operation,high reliability and low noise during operation,and the bushing surface is in a completely lubricated state,which effectively reduces the friction loss during work,therefore,it has been widely used in large-scale water conservancy and hydropower,aerospace engineering and heavy machinery industries.As the core component of the oil film bearing,the stability of the bushing directly affects the safe and reliable operation of the rolling production line.However,in the complex and changeable actual working conditions of the oil film bearing,in its most vulnerable and failure parts,in addition to the surface of the bushing,there is a bonding interface between the cladding and the base layer.In the traditional molding process of the bushing,the centrifugal casting process has many technical deficiencies and defects.A new type of welding process replaces the traditional casting process,basically avoiding the disadvantages of the traditional process,and the welding quality can fully meet the needs of actual production.With the continuous development of my country’s modernization,the process of industrialization also puts forward higher requirements for bearing performance.Based on the welding process,In this paper,the theoretical derivation of the interface fracture mechanics,the establishment of the interface crack mechanics model and the experimental study of the interface fracture mechanics of the bearing bush are carried out on the laminated material.The main research contents are as follows:First,the calculation formula near the crack tip is deduced and t and analyzed the distribution law of crack tip stress and displacement,it is concluded that the distribution of stress is mainly related to the stress oscillation zone,the oscillation influence zone and the embedded zone;In order to get rid of the influence of the stress oscillation on the crack model,this paper proposes a sophisticated elastoplastic finite element method;Determine the size of the contact area through an efficient elastoplastic numerical analysis method for analyzing the contact problem of interface cracks;Based on the similarity principle in the interface problem,a calculation model of the interface stress intensity factor with actual physical significance is established.Then,according to the characteristics of the interface problem,the interface failure criterion is established.Based on the tortuous failure criterion of homogeneous material cracks,derive the calculation formula of the stress field of the interface crack tip,and apply the maximum tangential stress theory to establish the tortuous failure criterion of the interface crack when the oscillation factor of the interface crack is zero and non-zero;In addition,based on the minimum strain energy density theory,a corresponding tortuous failure criterion of interface cracks is established.The criterion is based on the calculation of the tortuous failure direction.After the direction is obtained,the failure of similar homogeneous materials is used as the criterion for fracture.Then,the corresponding failure criterion was established according to the failure form of the interface crack.Based on the tortuous failure criterion of homogeneous material cracks,the calculation formula and stress intensity factor of the interface crack tip stress field are derived,and apply the maximum tangential stress theory and the minimum strain energy density theory to establish the tortuous failure criterion of the interface crack.In order to characterize the bonding performance of the interface between the welded babbitt alloy and the matrix,a three-point bending mechanics test program was carried out;Based on the theory of fracture mechanics and interface mechanics,the corresponding mechanical model of interface cracks was established and the formation mechanism of interface cracks was analyzed;Using the finite element method to simulate the growth process of the interface crack,the critical energy release rate of the interface crack and the stress phase angle at the crack tip are calculated through the virtual crack growth theory and energy formula.The analysis of the mechanism of interface crack initiation and propagation is completed,and the interface bonding performance is comprehensively evaluated.Finally,in order to improve the bonding quality of the bearing babbitt alloy,the effect of different heat input parameters on the bonding performance of the babbitt alloy and the bearing substrate during the welding process was studied.Bushing in the welding process under the three heat input parameters of the bonding performance to make a longitudinal comparison,as well as with the centrifugal casting process for the bonding performance of the horizontal comparison,and focus on the analysis of the microstructure and mechanical properties of the welded pasteurized alloy.