Effect Of Heat Treatment On Mechanical Properties Of 42CrMo/Q235 Cross-wedge Rolling Laminated Shaft Interface

A shaft is one of the main parts that make up a machine.The transmission moment of axle parts is often the most effective part of the outer edge,and the transfer efficiency of the central part is often low,and the central part is "dead weight" in some degree.Most of the shaft parts are used in high temperature,high pressure,and complex environment such as stress field and temperature field.How to improve the service performance of shaft parts in complex environment is a popular research direction at present.One idea is to develop new material alloys with excellent properties such as high temperature resistance and wear resistance,or to use rare metals as processing materials,but the cost of manufacturing production will be significantly increased because of the great prolongation of the development cycle of new materials.With the in-depth study of experts and scholars,a new idea is put forward,which is remanufacturing and repairing the raw materials,and coating the surface of the raw materials with the functions of corrosion resistance and insulation.But the thin thickness of the coating often leads to the poor wear resistance of the coating and the easy separation of the coating and the base material.Considering that layered composites can combine the properties of different kinds of materials and show different properties at different levels,the solution of composite laminates is proposed.Under the action of high temperature and high rolling force of cross wedge rolling,the contact surface of the interference fit is broken,and the atoms are diffusing each other under high temperature and high pressure.The metal bonds are regenerated to obtain the clean surface,thus the metallurgical bonding between different metal contact interfaces can be achieved.In this paper,the interfacial properties of the interface mechanical properties,microstructure,tensile fracture morphology and element diffusion of the 42CrMo/Q235 composite axis of cross wedge rolling under different heat treatment processes are mainly studied,and it is judged whether the interface of the cross wedge rolling composite shaft is improved after different heat treatment processes.It is reasonable to deduce the appropriate heat treatment process for 42CrMo/Q235 laminated axle.The experimental results show that after 1100 C quenching at 300,350 and 400 C,the fracture source of the fracture oxide is reduced first and then the new carbide fracture source is generated by SEM,and the interfacial bonding strength increases first and then decreases,and the Cr element is gradually transferred to the Q235 side as the tempering temperature rises,which is generated nearthe Q235 side of the interface.The hardness of 42 CrMo near the interface is decreasing,and the hardness of Q235 near the side is slightly increased.The hardness of the Cr element decreases as a result of the change of the two sides of the matrix,and the microstructure of the Q235 pearlite will become fine with the increase of the temperature,but the diffusion depth is limited,so the distance is far from the boundary.The crystal cells grow up and appear lumpy.Changing tempering time,quenching at 1100 C and tempering at 350 C for 45 min,the oxide at the interface is basically eliminated and the bonding strength is the largest.With the prolongation of holding time,carbide particles are precipitated at the interface,and the bonding strength decreases again.After 1100 C quenched at 600,700,800 C for one hour,it was found that a large number of irregular massive carbides were precipitated at the interface after annealing at 600 C.After annealing at 700 centigrade,the interface carbide was transformed into fine spherules.After annealing at 800,the interface Spheroides grew greatly,and the interfacial bonding strength increased first.As the annealing temperature rises,more Cr elements are transferred to the Q235 side,but because of the decarburization of the steel at high temperature,the carbon oxidation reaction in the steel becomes methane and other gas escapes,so the hardness near the 42 CrMo side and the Q235 side of the interface decreases;the Q235 side pearlite near the interface is in the vicinity of the interface.As the temperature rises,the tissue grows into a piece and presents a transitional structure under the microscope.In this paper,the effect of heat treatment on the mechanical properties of the interface of cross wedge rolling is studied.By explaining the change of mechanical properties of the interface from the angle of microstructure,the experimental basis is provided to optimize the heat treatment process of the composite shaft interface and to improve the bonding strength of the interface,and the rolling compound forming of his heterogeneous metal material is also studied.And the interface combined with heat treatment technology has laid the foundation.