Shear-extrusion process and its forming parameters are proposed, whilst its laborsaving characteristic is utilized to forge large-size shutoff valve bodies on the middle-due press. This new process is intended for the...Shear-extrusion process and its forming parameters are proposed, whilst its laborsaving characteristic is utilized to forge large-size shutoff valve bodies on the middle-due press. This new process is intended for the manufacture of large-size forged tubular components with branches on the middle-due press. Experiments are carried out and processing parameters are obtained regarding the shear- extrusion process of a large-size shutoff valve body. Deformation and metal flow in the shear- extrusion process are investigated. In order to verify the laborsaving characteristic of this new process, some contrast experiments of extrusion force are performed between shear-extrusion and upsetting-extrusion for forming tubular components with branches. Based on rigid-plastic FEM, a plane-strain model is established to analyze shear-extrusion process of tubular components with branches. The analysis results by 2-dimensions FEM are comparatively well consistent with experimental results. Both simulated and experimental results show that this new forming process is feasible for forging large-size tubular components with branches on the middle-due press.展开更多
The aging-hardening kinetics of powder metallurgy processed 2014Al alloy and its composite have been studied. The existence of n-SiC particulates leads to the increase of peak hardness. Interestingly, the aginghardeni...The aging-hardening kinetics of powder metallurgy processed 2014Al alloy and its composite have been studied. The existence of n-SiC particulates leads to the increase of peak hardness. Interestingly, the aginghardening peak of the composite takes place at earlier time than that of the unreinforced alloy. Transmission electron microscopy（TEM） studies indicated that the major precipitation phases are Al_5Cu_2Mn_3 and θ′（Al_2Cu）. Besides, Ω phase appeared in both specimens at peak hardening condition, which has been rarely observed previously in aluminum metal matrix composites without Ag. Accelerated aging kinetics and increased peak hardness may be attributed to the higher dislocation density resulted from the mismatch of coefficients of thermal expansion between n-SiC and 2014Al matrix. The results are beneficial to fabricating high performance composites for the application in automobile field such as pistons, driveshaft tubes, brake rotors, bicycle frames, railroad brakes.展开更多
文摘Shear-extrusion process and its forming parameters are proposed, whilst its laborsaving characteristic is utilized to forge large-size shutoff valve bodies on the middle-due press. This new process is intended for the manufacture of large-size forged tubular components with branches on the middle-due press. Experiments are carried out and processing parameters are obtained regarding the shear- extrusion process of a large-size shutoff valve body. Deformation and metal flow in the shear- extrusion process are investigated. In order to verify the laborsaving characteristic of this new process, some contrast experiments of extrusion force are performed between shear-extrusion and upsetting-extrusion for forming tubular components with branches. Based on rigid-plastic FEM, a plane-strain model is established to analyze shear-extrusion process of tubular components with branches. The analysis results by 2-dimensions FEM are comparatively well consistent with experimental results. Both simulated and experimental results show that this new forming process is feasible for forging large-size tubular components with branches on the middle-due press.
基金Financial support by the National Basic Research Program of China(“973”Program,No.2012CB619600)the National Natural Science Foundation of China(No.51474111)+2 种基金the Science and Technology Development Project of Jilin Province(No.20160519002JH)support came from the Fundamental Research Funds for the Central Universities(JCKY-QKJC02)the Chang Bai Mountain Scholars Program(2013014)
文摘The aging-hardening kinetics of powder metallurgy processed 2014Al alloy and its composite have been studied. The existence of n-SiC particulates leads to the increase of peak hardness. Interestingly, the aginghardening peak of the composite takes place at earlier time than that of the unreinforced alloy. Transmission electron microscopy（TEM） studies indicated that the major precipitation phases are Al_5Cu_2Mn_3 and θ′（Al_2Cu）. Besides, Ω phase appeared in both specimens at peak hardening condition, which has been rarely observed previously in aluminum metal matrix composites without Ag. Accelerated aging kinetics and increased peak hardness may be attributed to the higher dislocation density resulted from the mismatch of coefficients of thermal expansion between n-SiC and 2014Al matrix. The results are beneficial to fabricating high performance composites for the application in automobile field such as pistons, driveshaft tubes, brake rotors, bicycle frames, railroad brakes.
