Study On Drawing And Heat Treatment Process Of 6056 Aluminum Alloy Wire

With the development of automobile lightweight,aluminum alloy has been widely used in automobile manufacturing.But the connection technology has been regarded as the key technology for the effective promotion of vehicle lightweight.A series of problems exposed by the traditional steel bolted aluminum alloy parts restrict the comprehensive promotion of aluminum alloy materials in the automotive field to a certain extent.Therefore,the research of high strength aluminum alloy bolts has become a hot spot in the field of aluminum alloy processing at home and abroad.6056 aluminum alloy is a heat treatable strengthening alloy,which has high strength after T6 heat treatment,and its weldability,corrosion resistance and machinability are better than 7050 and 2024 aluminum alloys,so it is very suitable for the preparation of aluminum alloy bolts.In this paper,the drawing process and T6 heat treatment process of 6056 aluminum alloy wire were studied and discussed.Firstly,the microstructure and mechanical properties of 6056 aluminum alloy extruded bar were observed and tested,and then the single pass drawing process of 6056 aluminum alloy was studied.The effect of drawing speed on single pass ultimate deformation was studied,and the reason of wire drawing fracture was discussed.Besides,the variation of microstructure and properties of 6056 aluminum alloy with single pass drawing deformation was studied by microstructure observation,mechanical properties and electrical conductivity test.Secondly,the accumulative limit deformation of 6056 aluminum alloy wire was studied when the deformation between passes was 10%,and the evolution law of microstructure and properties of wire in multi pass continuous drawing process was mainly discussed.By comparing and analyzing the influence of deformation between passes on the properties of final drawing wire,the reasonable drawing process of 6056 aluminum alloy wire was established.Finally,the T6 heat treatment process of the drawn wire was studied.The effect of heat treatment parameters on the microstructure and properties of 6056 aluminum alloy wire was studied by changing the solution temperature,aging temperature and aging time.And according to the research results,a reasonable T6 heat treatment process of 6056 aluminum alloy wire was established.The main conclusions are as follows(1)The microstructure of extruded bar of 6056 aluminum alloy is fibrous,and the second phase in the alloy distributes along the direction of extrusion deformation.The tensile strength,yield strength,elongation,hardness and conductivity are 242MPa,185MPa,13.65%,68.5HV and 48.29%IACS respectively.(2)The drawing speed has a certain influence on the single pass ultimate deformation of 6056 aluminum alloy wire.When the drawing speed is too fast,the single pass ultimate deformation will decrease.When the drawing speed is 10m/min,the single pass limit deformation of wire rod is 34.82%～42.56%.With the increase of single pass drawing deformation,the strength and hardness of 6056 aluminum alloy wire increase,the plasticity decrease and the conductivity decrease.(3)Through the study of multi pass continuous drawing process of 6056 aluminum alloy,it is found that when the average deformation between passes is 10%,the cumulative limit deformation of wire is more than 90%.With the increase of cumulative deformation,the strength and hardness of wire increase,the elongation decreases and the conductivity decreases.It is found that the higher the deformation between passes,the higher the strength and hardness,and the lower the elongation.(4)It is found that recrystallization of 6056 aluminum alloy wire occurs when solution treatment is carried out in the range of 530℃ to 560℃.In this temperature range,the higher the solution temperature is,the less the residual phase is.The higher the strength and hardness of the wire after the same aging system(170℃/8h),the lower the elongation.When the aging temperature is fixed,with the extension of aging time,the strength and hardness of wire increase rapidly at first,and then decrease gradually after reaching a certain peak value,while the elongation first decreases rapidly,and then increases after passing the peak aging point.The electrical conductivity increases with aging time.The higher the aging temperature is,the shorter the peak aging time is.