Research On The Isothermal And Local Loading Forming Of Ribs

In order to meet the lightweight of the aerospace, military and other high-endequipment manufacturing, a large number of parts are developing toward the directionof large, complex, complicated cross-section. light alloy materials of complex ribs areapplied more and more wide spread.Currently, the main processing of rib pieces ismachining and precision casting, the former makes the mechanical properties of theparts greatly reduced, because of the metal linear flow being destructed. whileprecision casting has uneven microstructure and micro-defects, which is generallyapplicable to the performance of not too high occasions.This topic put forward by theforming process of isothermal and local loading,The complex rib piece was studied bytheoretical analysis and finite element simulation.In the finite element analysis software DEFORM-3D.Different Loading modesare adopted such as the overall loading forming, pre-forging+overall loadingforming and pre-forging+local loading forming.numerical simulation on7075aluminum alloy ribs, has mainly analyzed of the material filling law and the impact ofload conversion law.Compare various process，high ton, multiple defects in the highgluten and thin-walled,the load reached more than50000kN,when adopted overallloading. which could not meet the conditions requires. But the tonnage is still in27000kN and folding defects is generated at high gluten.Before overall loading,weincrease the pre-forging step to improve the material fluidity,reduce the someforming load and improve the forming defect. Load can be reduced to about5000kN,and forming defects such as folding, wear bars is basically avoided.The article analyses the selection of the key process parameters such as moldingtemperature, load, speed, friction factor on local loading forming. formingtemperature of blank and mold is selected at450℃, load is smaller,mechanicalproperties of forging is good.As the the speed increases, the overall temperature of theblank rises. While the speed is too fast, it may cause some of the prior deformationzone overfiring. Considering, speed is selected as0.5mm/s.The friction factor hasno significant effect on the local loading forming.by choosing the specific pointtracking method, Compare different process about material filling law anddeformation uniformity. We use forming process of local loading-whole loadingHeight difference among material filling in the deformation zone reduces anddeformation is more uniform, forgings end has more flat. Reasonable parting surfaceposition,the impact of load passes to the metal flow line is analyzed.It can supply areference for depth study of the rib pieces forming.During forming,the deformation resistance of the aluminum ribs is large, there isstill some deficiency. We explore ZK60magnesium alloy as the material of ribs pieces.We obtained the ZK60of stress-strain curve through high temperaturecompression tests, established a high-temperature flow stress model. ImportedDEFORM-3D software for numerical simulation. Research is studied on equivalentstress, equivalent strain, Damage, temperature field and load variation.In contrast to the forming of the aluminum alloy，ZK60rib’s Material filling thesituation is basically the same,And ZK60of forming load higher than7075about500kN,easier overheating and over-burning at high temperatures. It can provide areference for study the subsequent-magnesium alloy isothermal local loading forming.Critical process parameters in the local loading forming are analyzed, such as formingtemperature, loading, speed, friction factor.And the partition of reasonable load,parting surface location and the affect of load passes in the metal flow lines.Whichcan provided a reference depth study of the ribs.