• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.414-417
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• 2003

A copper-clad aluminium composite bar is lighter and less expressive than a commercial copper alloy bar. Copper-clad aluminium composite bar can be fabricated by hot hydrostatic extrusion process. In this work, the effect of die angle on the compressive properties of copper-clad aluminium composites fabricated using hydrostatic extrusion process was investigated experimentally. The results showed that optimum half die angle was in the range of 40$^{\circ}$ to 50$^{\circ}$ for an extrusion ratio of 19. The results also showed that the half die angle had little influence on the compressive strength of copper-clad aluminium composites. A diffusion layer increased with increasing die angle.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.10
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• pp.1541-1550
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• 2001

This paper describes experimental investigations in the direct extrusion of copper clad aluminum rods through conical dies. Composite materials consist of two or more different material layers. Copper clad aluminum composite materials are being used fur economic and structural purposes and the development of an efficient production method of copper clad aluminum composite material rods by extrusion is very important, It is necessary to know the conditions in which successful uniform extrusion ,and sound cladding may be carried out without any defects in the direct extrusion. There are several variables that have an influence on determining a sound clad extrusion. In order to investigate the influence of these parameters on the hot direct extrudability of the copper clad aluminum composite material rods, the experimental study have been performed with various extrusion temperatures, extrusion ratios and semi-cone angles of die. Subsequently, the microscopic inspection of interface bonding is carried out for extruded products. By measuring hardness, along extrusion way of products, a variation of hardness has been discussed. Proportional flow state has been considered by measuring radius ratio of Cu sleeve and Al core before and after extrusion.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.437-440
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• 2000

Composite material consists of more than two materials and make various kinds of composite materials by combining different single materials. Copper clad aluminum composite material is composed of Al and Cu, and it has already been put to practical use in Europe because of its economic benefits. This paper presents the interface bonding according to the variation of extrusion ratio and semi-angle die by observing the interface between Cu and Al using metal microscope. By that result, we can predict the conditions of the interface bonding according to the extruding conditions.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.759-765
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• 2000

A composite material consists of two or more different material layers. Copper clad aluminum composite materials are being used for economic and structural reasons. This study is concerned with experimental investigation in the direct extrusion of copper clad aluminum rods through conical dies. The suggestion are given for the proper extrudability of copper clad aluminum rods via hot direct extrusion. This paper presents the variation of flow state and hardness at a variable of extrusion ratio and semi-angle of die. By measuring after and before extrusion radius ratio of Cu sleeve and Al core, proportional flow state has been considered. And also by measuring hardness, through extrusion way, a variation of hardness has been considered.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.128-131
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• 2004

Magnesium alloys are being extensively used in weight-saving applications and as a potential replacement for plastics in electronic and computer applications. Magnesium alloy has some good characteristics, EMI shielding property and high specific strength. Nevertheless their high brittleness make it uneasy to process the magnesium. Magnesium alloys are extruded like aluminium alloys. The present work was done to find a characteristic of magnesium alloy(AZ31) changing the extrusion ratio 8.5, 19.1, 49 respectly and changing the die half angle $30^{\circ},\;45^{\circ},\;60^{\circ}$. Here this present done by the hydrostatic extrusion in the hot condition, $310^{\circ}$. The higher the extrusion ratio goes, the higher the extrusion force goes.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.89-92
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• 2004

This paper is concerned with the drawing process of Al-Si wire. In this study, the finite-element model established in previous work was used to analyze the effects of various forming parameters, which included the reduction in area, the semi-die angle, the aspect ratio and the inter-particle spacing of the Si in drawing processes. The finite-element results gave the consolidation condition. From the results of analysis, the effects of each forming parameter were determined. It is possible to obtain the important basic data which can be guaranteed in the fracture prevention of Al-Si wire by using FEM simulation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.463-466
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• 2005

Restoring ductility or removing residual stresses is a necessary operation when a large amount of cold working is to be performed, such as in a cold-forging or warm forging process. The advantage of annealing temperatures was investigated. After Hydrostatic Extrusion process, extruded materials were annealed at $200^{\circ}C,\;350^{\circ}C,\;450^{\circ}C$ for 1 hour. Microstructure of the annealed material was observed to make an understand about the difference in mechanical properties.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.27-30
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• 2004

Clad wire , which has the advantages of the high strength of a steel core and the electro-conductivity, corrosion resistance of a copper layer, is widely being used the telecommunications, electric-electronic and military technology industries, among others. It is important to obtain uniform coated rate when producing clad wires. Clad wire drawing process can be influenced on damage and coated rate of core and sleeve by process variables as semi-die angle and reduction in area. Therefore, in this study, the finite-element results established in previous study is used to analyze the effect of the various forming parameters, which included the semi-die angle, reduction in area etc. The coated rate will be predicted with observation copper coated rate variation according to total reduction in area and the optimal pass schedule will be set up through proper reduction in area and semi-die angle variation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.144-147
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• 2005

In hydrostatic extrusion the billet in the container is extruded through a die with a liquid acting as a pressure medium, instead of by the direct application of the load by a ram. And the extrusion pressure can be affected by the flow stress and they are affected by the temperature. So in this study the temperature is the main issue with a extrusion ratio and a half die angle. As extrusion temperature goes down from $300^{\circ}C$ to $200^{\circ}C$, tensile strength goes up to 310MPa. Because velocity of extrusion is higher than the conventional extrusion, there is another characteristic in the sense of microstrure. The temperature was sotted to $300^{\circ}C,\;250^{\circ}C,\;200^{\circ}C$, respectively. There is a increase of extrusion pressure abot $15\%$.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.6
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• pp.166-173
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• 2001

Composite materials consists of two or more different material layers. The usefulness of clad metal rods forms the possibilities of combination of properties of different metals. Copper clad aluminum composite materials are being used for economic and structural purpose. In this study, composite billet consists of commercially pure copper and aluminum(A6061) and experimental conditions consist of the combinations of clad thickness, extrusion ratio, and semi-cone angle of die. In order to investigate the influence of these parameters on the hot direct extrudability of the copper clad aluminum composite material rods, the experimental study have been performed with various extrusion temperatures, extrusion ratios, semi-cone angles of die, and composition rate of Cu:Al.