Development of technological extrusion process of oversized cup type part with spherical bottom and flange

Author(s):  
A.M. Dmitriev ◽  
N.V. Korobova

The stamping technology of hollow large-sized cylindrical parts with spherical bottom and fl ange made of AK6 aluminium alloy, the results of calculations for upsetting operation for preparing of the initial shape the workpiece, reverse extrusion of the workpiece by spherical end punch and its direct extrusion to thinning the forging wall are presented

2015 ◽  
Vol 1105 ◽  
pp. 182-189 ◽  
Author(s):  
Adnan I.O. Zaid ◽  
S.M.A. Al-Qawabah

Al-4% Cu alloys are now widely used in many engineering applications especially in robotic, aerospace and vibration control area. The main problem arises from the weakness of their mechanical characteristics. Therefore, this study is directed towards enhancing the mechanical properties through severe plastic deformation, hence it is anticipated that cold direct extrusion process may enhance their mechanical behavior. This was performed through using three different cross sectional dies namely; circular, square, and rectangular that have the same cross sectional area. The general microstructure, microhardness, and compression tests were performed on each specimen produced before and after extrusion for Al and Al-4% Cu alloy. It was found that the maximum enhancement in mechanical behavior was achieved after extrusion through the rectangular shape for both Al and Al-4% Cu alloy at 0.2 strain by 143% for Al and 134.8% for Al-4%Cu wt.; similarly the hardness of both of them was improved where a maximum of 141.8 % was obtained for Al-4% Cu wt. in case of rectangular cross sectional die.


2016 ◽  
Vol 61 (1) ◽  
pp. 433-438 ◽  
Author(s):  
W. Szymański

Studies were conducted to improve the mechanical properties of composites based on 7475 aluminium alloy reinforced with Al3Ti particles fabricated by the “in situ” process. The first step involved “dissolving” of titanium in the liquid aluminium alloy and fabricating in this way composite materials with different content of the reinforcing phase (15-45wt%). A relationship between the composite hardness and content of the reinforcing phase was confirmed. The second step involved the improvement of cohesion between the reinforcing particles and composite matrix. By extrusion of samples in semi-solid state, an average increase in hardness by 15-20% relative to the unextruded composite was obtained. In the third step, the fabricated composite was subjected to a heat treatment corresponding to the state T6 in 7475 alloy, which raised the hardness by about 30%. Structure examinations carried out by means of optical microscopy and scanning electron microscopies as well as the results of hardness measurements were described. They enabled estimating the effect of the content of produced Al3Ti particles, and of the extrusion process in semi-solid state and heat treatment parameters on the composite properties. In compression test, the yield strength and compressive strength of the heat-treated composites were determined.


2016 ◽  
Vol 61 (1) ◽  
pp. 405-410
Author(s):  
M. Bigaj ◽  
S. Boczkal ◽  
J. Żelechowski ◽  
M. Gawlik ◽  
M. Mitka

The results of studies carried out on the heat treated AZ61 magnesium alloy extruded by two methods, i.e. direct extrusion and continuous rotary extrusion, were presented. As part of the work, parameters of the T6 heat treatment were proposed and aging curves were plotted. The solution heat treatment process was accompanied by the grain growth. During artificial aging, due to the decomposition of solid solution, the β-Mg17Al12 phase was precipitated from the supersaturated α solution. It precipitated in a coagulated form at the grain boundaries and in the form of fine-dispersed plates arranged in a preferred direction relative to the grain orientation. Rods obtained by continuous rotary extrusion, unlike those made by the direct process, exhibited a low degree of texturing and lack of anisotropic properties.


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