• Journal of the Korean Ceramic Society
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• v.36 no.2
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• pp.178-185
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• 1999

For the process control of silicon nitride gelcasting, the composition effect of acryamide system on the viscosity of slip and mechanical property of gelcast green body were investigated. The slip was prepared by ball milling of silicon nitride suspension prepared with acrylamide monomer and polyelectrolyte dispersant after premixing them by attritor. The slip mixed with initiator was vacuum deaired and cast into molds, and then polymerized. The consolidated green body was obtained by drying the gelated slip. The viscosity measument and the diametral compression test was done to evaluate the rheological behaviro of slip and mechanical property of gelcast body, respectively. Experimental results showed that the high solid loading of silicon nitride slip was obtained up to 46 vol% with a low viscosity. The mechanical property of gelcast body mainly increased with increasing the concentration of monomer. The gelcast body was machinable above the ∼3 MPa of tensile strength. The relative density of pressured-sintered body was 98.5% at 1760$^{\circ}C$, 3 h.

• Transactions of Materials Processing
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• v.10 no.4
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• pp.294-301
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• 2001

The sensitivity method has been applied to find perform shape that results in the desired shape after foring. As a 2D example, initial shape of specimen for the cylinder shape without barrelling after forging has been found. The method is then applied to various shapes of 3D free forging and initial shapes of the corresponding specimens after forging have been found successfully The sensitivity method is proven to be an effective and accurate tool for the preform design.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.113-116
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• 1995

In this experimental study,aluminum hotforging was conduct to get superior pistion to cast piston. Cast structure of billet is destroyed, harmful defects is removed by forging process. We proposed the direction od die design by observing formability of product according to die shape. The microstructure of forged products with different preform was investigated to determine inital billet shape. We proposed appropriate heat treatment condition for improvement of mechanical properties.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.285-286
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• 2006

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.2032-2041
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• 2000

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.03a
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• pp.113-116
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• 1998

A derivative based approach to process optimal design in powder forging is presented. The process model, the formulation for process optimal design, and the schemes for the evaluation of the design sensitivity, and an iterative procedure for the optimization are described in detail. The validity of the schemes for the evaluation of the design sensitivity is examined by performing numerical tests. The capability of the proposed approach to deal with diverse process parameters and objective functions is demonstrated through applications to some selected process design problems.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.527-528
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• 2007

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.291-296
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• 2000

The sensitivity method has been applied to find perform shape that results in the desired shape after forging. As a basic example, initial shape of specimen for the cylinder shape without barrelling after forging has been found. The method is then applied to various shapes of 3D free forging and initial shapes of the corresponding specimens after forging have been found successfully. The sensitivity method is proven to be an effective and accurate tool for the preform design.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.17-18
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• 2007

• Journal of the korean Society of Automotive Engineers
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• v.13 no.6
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• pp.22-29
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• 1991

분말단조란 종래의 분말야금법으로 예비 성형체를 만든후 그것을 단조 소재로 열간단조를 통하여 최종 제품을 만드는 부품가공기술이다. 본 고에서는 분말단조의 이해와 선진국에서 개발에 성공한 사례 및 경제성을 조사함으로써 분말단조기술의 현황 파악 및 기술 축적을 도모하고자 하였다.