The Study On Hot Extrusion Forming Process Parameter And Workpiece Properties Of Tin Bronze

Tin bronze has excellent elastoplasticity and good mechanical properties of strength and hardness.It is widely used in the manufacture of some important mechanical parts,especially for bushings,turbines and other workpiece.It has excellent mechanical properties for tin bronze(QSn7-0.2)to strong spinning after hot extrusion.But the strong spin forming process requires the workblank have specific mechanical properties,especially for the plasticity.Therefore,it is particularly important to improve the mechanical properties of the workpiece by controlling the hot extrusion parameters.The process of hot extrusion is widely used in modern industry.The process is influenced by forming temperature,speed and friction,so that it becomes very complicate.When extruding,the material is strain-strengthened due to plastic deformation.Because of the high deformation temperature the metal will occur dynamic recovery and dynamic recrystallization.The different forming excent and temperature will directly influence properties of the formed workpiece.Different materials have different recrystallization temperatures and microstructure.So the hot extrusion process and forming quality are very different.This paper mainly studies the influces of workpiece`s mechanical qualities by technological parameter of tin bronze(QSn7-0.2)tubeler part.Simufact.forming is a finite element simulation software,it is exspecially used for metal plastic forming processing.It is suitable for simulation of various machining processes,including ring rolling,extrusion,warm forging,free forging and many other processes.Based on Simufact.forming simulation,it has established a finite element simulation model of tin bronze(QSn7-0.2)hot extrusion forming and studies the forming process of hot extrusion process.It use the methed of single factor test to study the effects of different extrusiontemperatures,speeds and friction coefficients on the mechanical properties of the drip molding,especially the plasticity of the workpiece.In this paper,we have using metallographic microscope and SEM observed and analyzed the microstructure and fracture morphology of the drip molding.Bying tensile experiment and hardness experiments explored the influence of hot extrusion parameters on the mechanical properties of hot extrusion,thus providing effective theoretical guidance for actual production.Through simulation and experimental verification,the following conclusions are drawn:in the forming process of connecting rod bushing by tin bronze(QSn7-0.2),we should control the temperature at 700-720 °C,the speed at 7 mm/s,friction coefficient should be controlled in 0.25,we can choose water-based graphite as lubricant.