Influence Of Process Parameters On Mechanical Properties Of 6082 Aluminum Alloy Forgings

6082 aluminum alloy is a typical 6xxx aluminum alloy.It has many advantages,such as good extrusion,forging and great corrosion resistance,so it is widely used.In this study,the surface coarse grain and mechanical properties of 6082 aluminum alloy parts during hot forming were studied.The effects of different processing conditions on the microstructure were studied by heat preservation test and thermal simulation compression test.Taking conical forgings as an example,the effect of solution aging process parameters on mechanical properties of 6082 aluminum alloy forgings was analyzed.Finally,through comprehensive analysis,reasonable forging forming and postforging heat treatment process parameters are determined.The main research work completed is:(1)The relationship between the thickness of coarse grained layer on 6082 aluminum alloy surface and heating temperature,holding time was obtained by heating and holding experiments in the temperature range of 400?~570? and holding time range of 15~60 minutes.The variation of the thickness of the coarse-grain layer on the undeformed aluminum alloy bar under different heating and holding conditions is as follows: the higher the temperature at the same holding time,the larger the thicker the coarse grain layer is.When the holding time is short,the thickness of coarse grain layer does not change obviously.After a certain time,the thickness of coarse grain layer begins to increase.(2)The thermal compression test of 6082 aluminum alloy cylindrical specimens was carried out by Gleeble-1500 D thermal simulator.Based on the measured flow stress curve,the constitutive model of 6082 aluminum alloy was established to prepare for the subsequent numerical simulation.The specimens after compression deformation at different temperatures and strain rates were analyzed by observing microscopic pictures.It is found that the distribution of precipitated phases is more and more dispersed with the increase of temperature at the same strain rate,the grain size increases with the increase of strain rate at the same deformation temperature,and the obvious mixing phenomenon occurs at lower deformation temperature.(3)With the help of numerical simulation,the conical forging of aluminum alloy was designed.The forging not only had extrusion deformation but also upsetting deformation in the forming process,which are typical.Based on this forging,a series of process tests were carried out to evaluate the effects of different process parameters on the mechanical properties of 6082 aluminum alloy forgings.Orthogonal test method was used to determine the optimal and suboptimal solution ageing treatment after forging,and two schemes were implemented to obtain the corresponding forgings.After that,the tensile specimens were taken at the center of the forgings to determine the related mechanical properties.The results show that at the same deformation temperature,the tensile strength of the forgings treated by the optimal solution ageing scheme is the highest,and the elongation of the forgings increases with the increase of the deformation temperature when the sub-optimal solution ageing scheme is adopted.(4)Taking the actual swing arm forging as an example,the process of the 6082 aluminum alloy forgings is determined: preheating to 540?,re-heating to 540? after pre-forging,final forging,followed by solid solution and aging treatment(solution temperature: 540?,solid solution holding time: 1.5h,aging temperature: 180?,aging holding time: 4.5h).