Research On Plastic Forming Process Of 7022 Aluminum Alloy Cam Swing Arm

In the textile machinery,the cam swing arm,which is one of the five major moving parts,keeps close contact with the contour surface of the conjugate cam and has been running at high speed,and reciprocates around the swing arm axis.To maintain a close fit,this condition requires good specific strength,wear resistance and fatigue resistance of the cam swing arm.The 7022 aluminum alloy can meet the requirements of strength and plasticity.Therefore,through the control of the forging process,it is important research to obtain a cam swing arm with good forming condition without any defects such as folding and so on.The main research contents of this paper are as followed:(1)For the cam swing arm blank with a double-layer asymmetric structure,the design of the pier,pre-forging and final forging die is completed according to the size and drawing requirements of the forging,and the best process route is determined through closed-loop optimization combining forging trial production and numerical simulation.For pier thickening-flattening-pre-forging-final forging,this process scheme can meet the forming performance and size requirements of the cam swing arm.(2)By analyzing the influence of the forming speed,friction coefficient and heat exchange coefficient of the billet making process on the billet temperature,it can be understood that with the increase of the forming speed,the decrease of the heat exchange coefficient and friction coefficient,the temperature of the billet will increase.Continuously increasing heat exchange coefficient will improve the uniformity of material temperature.The analysis of the stress field,velocity field and temperature field in the pre-forging process of the billet shows that the uniformity of the billet stress distribution is better when the billet temperature is 470 °C,and the stress concentration and wear of the die can be better alleviated whose service life can be extremely long.The folding and filling defects of the cam swing arm during the pre-forging process are solved by optimizing the fillet at the transition of the die.(3)Under the combined influence of deformation temperature and strain rate,the flow stress during forging of 7022 aluminum alloy cam swing arm will increase with the decrease of deformation temperature and the increase of strain rate.The review of Chinese and foreign literature shows that there is no constitutive equation of 7022 aluminum alloy.Therefore,the Arrhenius constitutive equation is constructed through high temperature compression experiments,and the relationship between flow stress,strain rate and temperature at high temperature is obtained.In the final forging process,the temperature field,velocity field and stress field of billet forming at 450 ℃ and 470 ℃ were compared,and it was found that properly reducing the material temperature under the premise of avoiding overburning can effectively reduce the stress concentration and stress concentration of the billet during forming.Improve the temperature uniformity,but also can effectively reduce the stress concentration of the mold and mold wear,and greatly improve the service life of the mold.(4)Precipitation strengthening accounts for about 66%-74% of the strengthening ratio of aluminum alloys.Therefore,adjusting the type,number and size of precipitation phases of 7022 aluminum alloy by adjusting the parameters of aging treatment can effectively improve the strength of the alloy.After analyzing the samples under different aging parameters,it is found that the temperature and time of aging treatment have a great influence on the microstructure and grain size of the county party committee.With the progress of the aging treatment,the number and size of the black second phase in the forging structure increases continuously,and the short rod-shaped η phase shows a trend of aggregation and distribution at the grain boundary,and the average grain size increases to a large extent.The hardness,electrical conductivity,tensile strength,yield strength and elongation of the forging samples all shows a trend of increasing and then decreasing with the increase of aging temperature and time,and the toughness of the samples decreases to a certain extent.The microstructure analysis of the sample fracture finds that there are a large number of coarse cleavage planes and tear ridges.This topic combines forging process design,finite element simulation and orthogonal test to solve the forging forming problem of 7022 aluminum alloy cam swing arm blank,and studies the change of forging structure and properties under different aging parameters.Forging and forming of 7022 aluminum alloy products provide theoretical basis and technical support.