• 지반과기술
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• v.7 no.3
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• pp.35-38
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• 2010

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.257-264
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• 2001

국내 고속철도 강합성 교량이 경부고속철도 8-2공구에서 처음으로 시공완료 되었다. 그동안 수년간에 걸쳐 고속철도 교량시공에도 불구하고 강합성 교량이 적용되지 못했던 것은 설계 기술적인 면과 더불어 재료 적인 면에서 국내여건이 성숙되지 못한 요인이 크다고 보여진다. 본 고에서는 기 설계된 PC BOX교량중 지형여건상 강합성교량이 적합한 교량구간을 제시하였다. 또한 강합성 교량의 설계기술적인면 중 특히 중요한 한국형 TGV차량의 동적 하중의 적용과 그에 따른 구조물 거동의 평가를 1＠50 교량에 대한 8-2공구 사례를 통하여 논의하였다. 강합성 단면은 단순 2주형 주형거더(double I beam)이며 플랜지 두께는 최대 80-100mm가 적용되어졌다. 본 단면에 대한 HL차량하중등에 대한 정적해석을 통하여 관심이 되고 있는 플랜지등의 응력 검토결과를 보여주었다. 아울러 정적해석과 동적해석의 결과치를 비교하여 국내 시방서에 제시된 고속철도 HL차량하중에 대한 평가도 이루어졌다. (중략)

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.103-103
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• 2011

본 연구에서는 TiN/ZrN 복합층을 STD 61 공구강 표면에 마그네트론 스퍼터링 (magnetron sputtering) 방법을 이용하여, 표면온도, 스퍼터링 파워, 시간, 버퍼층의 두께에 따른 변수를 두어 실험하였다. 표면 특성을 알아보기 위해 OM, FE-SEM, AFM, EDS, XRD, XRR 그리고, 긋기 및 나노경도 시험을 시행하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.8-13
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• 1996

A relatively new non-traditional finishing process called Abrasive Flow Machining(AFM) is being used to deburr, polish and radius workpiece or produce compressive residual stresses by flowing an abrasive-laden viscoelastic compound across the surface to be machined. This paper presents the effects of AFM on surfaces of tool steel produced by EDM and W-EDM. Using AFM, white layer produced by EDM is erased almost equally and the amount of metal removal is significantly affected the initally machined surface condition of workpiece. The dimension of workiece is enlarged and its surface roughness is improved as AFM time is increased. The optimal AFM time can be established from the experimental results. It is considered that the grinding method lide AFM is useful to grind complex or slim geometry of workpiece even. Scanning Electron Microscopy(SEM) was used to study the surface characteristics of the workpiece before and after AFM.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.04a
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• pp.93-104
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• 2002

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1997.04a
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• pp.13-13
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• 1997

• Journal of the Korean Society for Precision Engineering
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• v.15 no.4
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• pp.27-35
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• 1998

Ni-based heat resisting alloys are commonly used for high temperature applications such as in aircraft engines and gas turbines. In this work, the machinability of Nimonic 263 alloy is investigated with respect to optimum tool type and cutting conditions for both continuous and discontinuous machining as well as weld region. Among the five types of tools tested, K25 tool experienced the least of damage in machining the weld region. Furthermore, despite their superior high temperature hardness, Si-Al-O-N and CBN tools peformed poorly in machining Nimonic 263.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.211-211
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• 2009

높은 이온화율과 복잡한 형상의 모재에도 표면 도포성 및 균일성을 나타내는 아크이온플래이팅 기술과 비전도성 세라믹 타겟물질에 적용가능한 스퍼터링 기술이 결합된 하이브리드 코팅 시스템(Hybrid coating system)을 이용하였다. 그리고 Cr-Al-N과 Cr-Si-N 코팅막의 강화 기구를 복합시킨 새로운 개념의 Cr-Al-Si-N 코팅막을 초경(WC-Co)시험편에 증착하여 Si 첨가량에 따른 미세구조의 미세경도 특성을 파악하였다. 공구성능 평가는 고속가공조건하에 마이크로 밀링기에서 무코팅(초경공구), Cr-Al-Si-N (Si : 0, 4.5, 8.7, 16 at.%) 코팅 마이크로엔드밀에 대하여 공구마멸에 대한 공구수명을 비교, 평가하였다.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.8
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• pp.33-38
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• 1998

TiYN coated high speed steel tools have been developed and their tool lifes were assessed. First yttrium alloyed titanium target was manufactured, then using the arc ion plating(AIP) technique TiYN coating was deposited onto high speed steel substrate. Three kinds of varying thickness of TiYN coated tools were prepared. Cutting tests were carried out with theses tools and for comparison with the commercially available uncoated, TiN, TiCN and TiAlN coated tools. During the cutting tests flank wear width vs. cutting time was measured. It has been revealed that the newly developed TiYN coated tools show superior tool life characteristics to others.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1290-1295
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• 1988

Theoretical considerations in the development of new cutting tool materials for high speed machining is presented. The progressive wear of cutting tools is assumed to consist of the abrasive and solution components as major modes. Theoretical calculations of relative wear rates between various tool materials based on the two modes are possible using their hardness and solubility data. Assuming cementite as the major hard particles in machining steels, relative wear rates of possible tool materials were calculated. The results indicate that $Al_{2}$O$_{3}$ in oxides, HfN in nitrides and HfC in carbides are the optimal tool materials from the view point of mechanical and thermochemical wear resistance. And several methods for improving the fracture toughness of the above tool materials are suggested.