Study On The Effect Of Cold Compression For Quenching Residual Stress Of 7050 Aluminum Alloy Forgings

For 7050 aerospace aluminum alloy forgings, usually go through the solid solution process to meet the requirements of mechanical properties such as strength and toughness. However, the quenching process will also form residual stress in the inner and the surface of the forging. Quenching residual stress of forgings will not only affect the mechanical properties, such as the material static strength, resistance to stress corrosion and fatigue properties, but also affect the size and shape stability in the subsequent machining process.Aiming at 7050 aluminum alloy forgings quenching residual stress formation and cold compression,the stress evolution law in the quenching process and the effects of forgings size on the residual stress were studied by simulation and experimental methods. Analyze the effect and law of cold compression on the quenching residual stress and the material strength. The main research contents are as follows:(1) By using ABAQUS finite element software, through the simulation of different size of aluminum alloy rectangular quenching process, reveals the stress evolution law in the quenching process, the distribution of quenching residual stress and the effect of the component sizes on residual stress.(2) In view of the residual stress field in the specimen, the effect of cold pressing deformation on the residual stress of the sample was analyzed by using the method of experiment and numerical simulation. The surface residual stress of the specimen was tested by X-ray diffraction method. At the same time, the influence of cold compression on the strength of 7050-T7452 aluminum alloy was studied by micro tensile test.(3) For the quenching residual stress reduction technology of the large 7050 aluminum alloy forging, proposed the multi-step symmetric cold pressing process. The influence of the process parameters on the variation of residual stress was analyzed by the finite element numerical simulation analysis. Based on the comprehensive consideration of the reduction of the residual stress and the strength of the material, the optimum cold pressing process of the given forging is determined, which the reduction is 1%, the die mold rate is 50% and the die width is 1.5 times the thickness of the forging.