Research On T7452 Process Of Aviation Die Forging Of 7050 Aluminum Alloy

To ensure that the strength meets the standards of aluminum alloy of aviation die forgings,solution treatment and quenching is necessary.However,if the aluminum alloy forgings are quenched,it will not only have large residual stresses and deformations more easily but also seriously affects subsequent cold working of the forging process to produce.Therefore,the cold compression needs to be introduced into the aluminum alloy of aviation die forgings after quenching.This paper studies the influence of the T7452process on microstructure and mechanical properties of aviation die forgings of 7050aluminum alloy,and provides a theoretical basis for optimizing the process.Through a quenching experiment and residual stress measurements for a ribbed aluminum alloy forging,the convective heat transfer coefficients were obtained.It was analyzed the flow field data for the surface between a web with rib and a web without rib during the quenching process and distribution of temperature field and stress field at different positions of forgings.The heat transfer coefficients were introduced into the quenching simulation of a long stringer forging consisting of rib-web forging and plate forging,and the influence of ribs on the residual stress and deformation of the forging was compared and analyzed.The effects of solution treatment,different cold pressing?0%,3%,7%,12%?and two-stage aging treatment on the microstructure and mechanical properties of 7050 aluminum alloy specimens were studied.The following conclusions were obtained:?1?In the film boiling phase,the flow field direction and flow rate was affected by the ribs at different positions of the rib-web forging,thereby resulting in the convective heat transfer coefficient following:the web below rib<the web below rib<the web without rib.?2?Compared with the plate long stringer forging,the end face of the long rib-web forging was reached the maximum offset by 1.5s,the value was increased by 5 times and the offset direction was completely opposite.At the end of the quenching,the final position of the rib-web forging deviated by 4.85 mm,and there were no changes for the plate forging.?3?Al₇Cu₂Fe,S?Al₂CuMg?and MgZn₂ were contained in 7050 aluminum alloy forging.After solution treatment at 477°C×1.5h,only Al₇Cu₂Fe was remained and the size decreased.The grain size and low angle grain boundary misorientation increased,and the hardness increased by 40⁵0HV.?4?The temperature at the transition point of GP zone solution,?phase precipitation and?phase solution decreased with the increase of cold pressure.The amount of cold deformation increased from 0%to 12%,the hardness increased from 155HV to 182HV,and the hardness decreased from 174HV to 153HV after two-stage aging treatment.