The triangular 2014 aluminium alloy forgings were made by a new process and the traditional process. The results showed that the mechanical properties of the forgings made by the new process are far higher than that i...The triangular 2014 aluminium alloy forgings were made by a new process and the traditional process. The results showed that the mechanical properties of the forgings made by the new process are far higher than that in the standard of GB223 84, and also higher than that in the standard of EL/53MI 94; moreover, the mechanical properties are almost the same in each direction, and anisotropies are very small. The grains and 2nd phases were analyzed by using TEM and SEM, the results indicate that very fine grains (3～6 μm)appear in an approximately isometric way, and a large number of 2nd submicrophases(0.05～0.15 μm) disappear in no apparently preferred orientation distribution because the new process involves multidirectional heavy plastic deformation (λ=12), solution(500 ℃/400 min) and ageing(165 ℃/10 h) heat treatments for a long time at high temperatures. These refined grains, 2nd submicrophases and their almost homogeneous distribution can make it possible for the forgings to display high mechanical properties.展开更多
A numerical approach for process optimization and microstructure evolution of lager-sized forging of aluminium alloy 7050 was proposed, which combined a commercial FEM code Deform 3D with empirical models. To obtain t...A numerical approach for process optimization and microstructure evolution of lager-sized forging of aluminium alloy 7050 was proposed, which combined a commercial FEM code Deform 3D with empirical models. To obtain the parameters of empirical constitutive equation and dynamic recrystallization models for aluminium alloy 7050, the isothermal compression tests of 7050 samples were performed on Gleeble-1500 thermo-simulation machine in the temperature range of 250-450 ℃ and strain rate of 0.01-10 s-1, and the metallograph analysis of the samples were carried out on a Leica DMIRM image analyzer. The simulation results show that the dynamic recrystallization in the central area of the billet occurs more easily than that on the edge. Repetitious upsetting and stretching processes make the billet deform adequately. Among several forging processes e.g. upsetting, stretching, rounding and flatting, the stretching process is the most effective way to increase the effective strain and refine the microstructure of the billet. As the forging steps increase, the effective strain rises significantly and the average grain size reduces sharply. Recrystallized volume fractions in most parts of the final forging piece reach 100% and the average grain size reduces to 10 μm from initial value of 90 μm.展开更多
The closed die forging(or fully-enclosed die forging) method was employed to form a rotor instead of the conventional machining method. A combined female die was designed so that the rotor could be released easily fro...The closed die forging(or fully-enclosed die forging) method was employed to form a rotor instead of the conventional machining method. A combined female die was designed so that the rotor could be released easily from the female die after forging. In order to improve the metal flow ability, the isothermal forming technique was introduced to the closed die forging process. On the basis of the rigid-viscoplastic FEM principle, the DEFORM 3D software package was employed to simulate the forming process. The simulation results illustrate that the deformation of different part of the billet is not the same. The material near the entrance of the die cavity is deformed greatly whose strain rate and strain are both large, while the deformation of the material at the billet center is much smaller.展开更多
The mechanism of forming defects in 2024. 7075 series aluminium alloy forgings has been studiedby means of metallography. EDAX. SEM etc. The defects are divided into two types by their appearance.needle-shaped and fla...The mechanism of forming defects in 2024. 7075 series aluminium alloy forgings has been studiedby means of metallography. EDAX. SEM etc. The defects are divided into two types by their appearance.needle-shaped and flake-shaped. The mechanism of them forming is discussed. It has been testified that thedefects result from hydrogen or oxide film. The defects can be prevented by controlling the hydrogen contentin the melt and keeping oxide film from involving.展开更多
The potential of cooling slope casting process to produce EN AW 6082 forging stock for the manufacture of EN AW 6082 suspension components was investigated.EN AW 6082 billets cast over a cooling plate offer a fine uni...The potential of cooling slope casting process to produce EN AW 6082 forging stock for the manufacture of EN AW 6082 suspension components was investigated.EN AW 6082 billets cast over a cooling plate offer a fine uniform structure that can be forged even without a separate homogenization treatment.This is made it possible by the limited superheat of the melt at the start of casting and the fractional solidification that occurs already on the cooling plate.Suspension parts forged from cast and homogenized billets with or without Cr all showed a umform structure,and the hardness reached HV 110 after the standard artificial ageing treatment.展开更多
Die forging process of piston tail and its key technology are analyzed in detail. The key issue is to reduce friction force between punch and billet to facilitate metal flow towards two ends. Three-step forging scheme...Die forging process of piston tail and its key technology are analyzed in detail. The key issue is to reduce friction force between punch and billet to facilitate metal flow towards two ends. Three-step forging scheme is used, namely preforming, final forging and cutting the flash. Preforming is critical for the success of the whole process and two schemes are compared. First two steps are simulated using 3D-Deform software. Simulation results show that the process is feasible and its validity is verified.展开更多
文摘The triangular 2014 aluminium alloy forgings were made by a new process and the traditional process. The results showed that the mechanical properties of the forgings made by the new process are far higher than that in the standard of GB223 84, and also higher than that in the standard of EL/53MI 94; moreover, the mechanical properties are almost the same in each direction, and anisotropies are very small. The grains and 2nd phases were analyzed by using TEM and SEM, the results indicate that very fine grains (3～6 μm)appear in an approximately isometric way, and a large number of 2nd submicrophases(0.05～0.15 μm) disappear in no apparently preferred orientation distribution because the new process involves multidirectional heavy plastic deformation (λ=12), solution(500 ℃/400 min) and ageing(165 ℃/10 h) heat treatments for a long time at high temperatures. These refined grains, 2nd submicrophases and their almost homogeneous distribution can make it possible for the forgings to display high mechanical properties.
基金Project(2005CB724105) supported by the National Basic Research Program of ChinaProject (IRT0549) supported by the Program for Changjiang Scholars and Innovative Research Team in University
文摘A numerical approach for process optimization and microstructure evolution of lager-sized forging of aluminium alloy 7050 was proposed, which combined a commercial FEM code Deform 3D with empirical models. To obtain the parameters of empirical constitutive equation and dynamic recrystallization models for aluminium alloy 7050, the isothermal compression tests of 7050 samples were performed on Gleeble-1500 thermo-simulation machine in the temperature range of 250-450 ℃ and strain rate of 0.01-10 s-1, and the metallograph analysis of the samples were carried out on a Leica DMIRM image analyzer. The simulation results show that the dynamic recrystallization in the central area of the billet occurs more easily than that on the edge. Repetitious upsetting and stretching processes make the billet deform adequately. Among several forging processes e.g. upsetting, stretching, rounding and flatting, the stretching process is the most effective way to increase the effective strain and refine the microstructure of the billet. As the forging steps increase, the effective strain rises significantly and the average grain size reduces sharply. Recrystallized volume fractions in most parts of the final forging piece reach 100% and the average grain size reduces to 10 μm from initial value of 90 μm.
文摘The closed die forging(or fully-enclosed die forging) method was employed to form a rotor instead of the conventional machining method. A combined female die was designed so that the rotor could be released easily from the female die after forging. In order to improve the metal flow ability, the isothermal forming technique was introduced to the closed die forging process. On the basis of the rigid-viscoplastic FEM principle, the DEFORM 3D software package was employed to simulate the forming process. The simulation results illustrate that the deformation of different part of the billet is not the same. The material near the entrance of the die cavity is deformed greatly whose strain rate and strain are both large, while the deformation of the material at the billet center is much smaller.
文摘The mechanism of forming defects in 2024. 7075 series aluminium alloy forgings has been studiedby means of metallography. EDAX. SEM etc. The defects are divided into two types by their appearance.needle-shaped and flake-shaped. The mechanism of them forming is discussed. It has been testified that thedefects result from hydrogen or oxide film. The defects can be prevented by controlling the hydrogen contentin the melt and keeping oxide film from involving.
文摘The potential of cooling slope casting process to produce EN AW 6082 forging stock for the manufacture of EN AW 6082 suspension components was investigated.EN AW 6082 billets cast over a cooling plate offer a fine uniform structure that can be forged even without a separate homogenization treatment.This is made it possible by the limited superheat of the melt at the start of casting and the fractional solidification that occurs already on the cooling plate.Suspension parts forged from cast and homogenized billets with or without Cr all showed a umform structure,and the hardness reached HV 110 after the standard artificial ageing treatment.
文摘Die forging process of piston tail and its key technology are analyzed in detail. The key issue is to reduce friction force between punch and billet to facilitate metal flow towards two ends. Three-step forging scheme is used, namely preforming, final forging and cutting the flash. Preforming is critical for the success of the whole process and two schemes are compared. First two steps are simulated using 3D-Deform software. Simulation results show that the process is feasible and its validity is verified.
