• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2004년도 추계학술대회논문집
• /
• pp.128-131
• /
• 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.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2012년도 춘계학술대회 논문집
• /
• pp.931-932
• /
• 2012

• 한국분말재료학회지
• /
• 제2권1호
• /
• pp.44-52
• /
• 1995

Effects of the extrusion temperature and die angle on the tensile properties of SiCIyAl composites in powder extrusion have been investigated. SiCP/Al composites were extruded at various extrusion temperatures (450, 500, $550^{\circ}C$) under the extrusion ratio of 25 : 1. The ram speed was maintained at 13 cm/min for all the extrusion conditions. The surface of the extruded rod appeared to be smooth without tearing at 450 and 50$0^{\circ}C$, whereas it was very rough due to tearing at $550^{\circ}C$. It was found that the tensile strength and elongation of the composites extruded at $500^{\circ}C$ are greater than those of composites extruded at $450^{\circ}C$ This is due to the easier plastic deformation of composite extruded at $500^{\circ}C$, compared with the composites extruded at $450^{\circ}C$. The effect of die angle was examined under 20=60, 120, $180^{\circ}$die angles at extrusion temperature of $500^{\circ}C$ under 25:1 extrusion ratio. The tensile strength of the composites extruded with 20=$60^{\circ}$approved to be higher than that of the composties extruded with 28 : 120 and $180^{\circ}$This is attributable to the higher extrusion pressure, which mixed composite powders could be densely consolidated at elevated temperatures, resulting from high friction force between billet and sliding surface of conical die.

• 한국산학기술학회논문지
• /
• 제19권7호
• /
• pp.50-55
• /
• 2018

압출기술에서 중요한 것은 금형의 설계 및 제작이며, 원하는 형태의 압출이 원활히 이루어지는 동시에 금형의 수명을 최대한 연장하고 효율성을 높이기 위한 금형의 설계가 필수적이다. 압출 온도, 압출 속도 등이 압출시의 주된 변수이며, 압출비 및 재료의 물성, 압출 형태에 따라 각기 다른 조건이 부가되어야 한다. 본 연구에서는 고속전철 내외장재 부품용 알루미늄 6xxx 계열 주조 합금의 압출공정에 대해 연구하였다. 6063, 6061, 6N01, 6005, 5083 and 6060 알루미늄 합금의 압출 금형 단면을 설계하였으며 이에 대한 실험을 실시하였다. 또한, 빌렛온도, 압출온도 및 재료의 변화에 따른 압출 압력과 같은 압출 조건들을 분석하였다. 6063 알루미늄 합금이 가장 낮은 온도와 압력에서 압출이 가능한 반면 6061 합금은 가장 높은 온도와 압력에서 압출이 가능하였다. 이들 실험결과로부터 수립된 조건들을 이용하여 성공적인 압출제품을 제조할 수 있었다.

• 소성∙가공
• /
• 제14권5호
• /
• pp.444-451
• /
• 2005

A new extrusion process of the circular section product with helical fins could be developed by rotating extrusion die. The twisting of extruded product is caused by the twisted conical die surface connecting the die entrance section and the die exit section linearly. But, until now, because the process has used fixed extrusion die, it needs high pressure in order to twist billet and form fin shape on the surface of billet. So, during extruding billet, in order not to twist billet, the extrusion die is needed to rotate itself instead of twisting of billet. It is known that it is possible to reduce extrusion load of product with helical fins by analysis and experiments using rotating die. And it is known that, through the extrusion load analysis by $DEFORM^{TM}-3D$ software, optimal rotational velocity of rotating die can be obtained according to reduction ratio of area and twisted angle of die. And experiments and analysis using rotating extrusion die show that the twisted angle of product can be controlled by twisted angle of extrusion helical die and the rotational velocity of extrusion helical die.

• 한국정밀공학회지
• /
• 제24권4호
• /
• pp.102-108
• /
• 2007

The characteristic properties of aluminum, high strength stiffness to weight ratio, good formability, good corrosion resistence, and recycling potential make it the ideal candidate to replace heavier materials in the car to respond to the weight reduction demand within the automotive industry. In this paper, FE simulation was carried out to design an appropriate extrusion die for the automobile control arm. Based on the FE simulation result, a new die design has been proposed for uniform material flow in the cross section of extruded product. And then the welding pressure, extrusion load, and the tendency of mandrel deflection were estimated to verify high quality. In the extrusion experiment, it was possible to produce sound product without defects.

• 소성∙가공
• /
• 제24권6호
• /
• pp.425-430
• /
• 2015

In the current paper, the effects of initial slug design on the earring of an Al rectangular battery case manufactured by impact extrusion were studied. During impact extrusion, non-uniform metal flow between the long and the short sides of the battery case leads to earring, which is subsequently trimmed. Process parameters such as friction, aspect ratio of the battery case, the die shape and the forming temperature tend to induce earring because they cause greater non-uniform metal flow. Large aspect ratio of the battery case and high friction between slug and die can greatly affect the earring of a rectangular battery case. To make a rectangular battery case without earring, it is necessary to control metal flow uniformly during impact extrusion. One of the ways to reduce the earring is to control the metal flow of slug at the initial upsetting stage. To analyze the effects of the initial slug design on earring, FE analysis was conducted using DEFORM 3D. Two types of initial slug designs were evaluated where volume was removed along either the width or thickness directions. The results show that the initial slug design can be effective in adjusting the uniformity of metal flow.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2001년도 추계학술대회 논문집
• /
• pp.97-101
• /
• 2001

Fine metal (Au, Ag, Cu) wire was extruded with hydrostatic extrusion process in cold condition. A vertical type 900kN hydrostatic extruder has been developed. The extruder was facilitated with high pressure container which are available for hot and cold forming. The container endured 1400MPa internal pressure and extrusion ratio To was achieved in cold forming for Au fine wire which had $600{\mu}m$ diameter. In contrast to the conventional macroscopic-sized-billet fine-wire requires higher extrusion pressure and effect of friction is much more significant.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2008년도 추계학술대회 논문집
• /
• pp.35-37
• /
• 2008

The light Mg alloys bearing the remarkably high strength, corrosion resistance and elevated temperature stability stand on the center of interest. The accomplishment so far is, however, only by alloy modification without any consideration on the rapid solidification effect. This work is to report not only the effect of rapid solidification of $MgZn_{4.3}Y_{0.7}$ alloy powders, but the extrusion behavior on the materials properties. The average grain size of the atomized powders was about $3-4{\mu}m$. The extrusion was carried out with the area reduction ratio of 10:1 to 15:1. As the ratio increased, homogeneous microstructure was obtained, and the mechanical properties such as tensile strength and elongation were simultaneously increased.

• 소성∙가공
• /
• 제19권6호
• /
• pp.352-356
• /
• 2010

This paper was designed to fabricate the micro-spur gear by the LIGA and hybrid powder extrusion process. It is important to manufacture a micro-die with a high aspect ratio and determine appropriate extrusion conditions for a microforming. Ni has been used to fabricate micro-dies. LIGA process was capable to produce micro-extrusion dies with close tolerance, longer bearing length and adequate surface quality. Superplastic Al-78Zn powders have the great advantage in achieving deformation under low stresses and exhibiting good micro-formability with average strain rate raging from $10^{-3}$ to $10^{-2} s^{-1}$ and constant temperature ranging from 503 to 563K. Al-78Zn powders were compacted into a cylindrical shape ($\Phi3\times$h10mm) under compressive force of 10kN and, subsequently, the compacted powders were extruded by the hybrid powder extrusion process controlling of the temperature holing time for a improvement on formability of Al-22Zn powder. Micro-extrusion has succeeded in forming micro-gear shafts.