• 한국분말재료학회지
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• 제20권5호
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• pp.366-370
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• 2013

The effects of $B_4C$ on the mechanical properties of WC/Ni-Si hardmetal were analyzed using sintered bodies comprising WC(70-x wt.%), Ni (28.5 wt.%), Si (1.5 wt.%), and $B_4C$ (x wt.%), where $$0{\leq_-}x{\leq_-}1.2$$ wt.%. Samples were prepared by a combination of mechanical milling and liquid-phase sintering. Phase and microstructure characterizations were conducted using X-ray diffractometry, scanning electron microscopy, and electron probe X-ray micro analysis. The mechanical properties of the sintered bodies were evaluated by measuring their hardness and transverse rupture strength. The addition of $B_4C$ improved the sinterability of the hardmetals. With increasing $B_4C$ content, their hardness increased, but their transverse rupture strength decreased. The changes of sinterability and mechanical properties were attributed to the alloying reaction between $B_4C$ and the binder metal (Ni, Si).

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 추계학술대회(한국공작기계학회)
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• pp.269-274
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• 2001

Applications of Brazing in the studying fields such as High-Speed Machining are very increasing in various industry fields. Therefore, Applying to the fracture mechanics by numerical analysis method is very important to analyse the crack problem Dissimilar Materials in Brazed Interface. In this study, Stress intensity Factor (S.I.F) is analysed to investigate crack behavior on the crack tip of dissimilar materials in brazed interface such as a Hardmetal and a HSS by two dimensional(2-D) Boundary Element Method (BEM). Kelvin's solution was used as a fundamental solution in BEM analysis and stress extrapolation method was used to determine Stress Intensity Factor.

• 한국분말재료학회지
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• 제5권4호
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• pp.303-311
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• 1998

Hard materials such as hardmetal, coated hardmetal, cermet, ceramics and diamond or c-BN sintered compact are a kind of grain-dispersed alloy with high volume of hard particles. These are used for cutting tools, wear-resistant tools, rock bits, high pressure apparatus, etc. The annual production in Japan is about 1.7 billion dollars (200 billion yen). This is greatly owed to the development in science and technology which has been accomplished by applying new concepts such as fine or uniform grain microstructure, orientation of crystal grains, functionally graded material, artificial lattice and coherent bonding in recent years. In this review, the development in recent years in Japan is briefly summarized.

• 한국공작기계학회논문집
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• 제11권6호
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• pp.91-97
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• 2002

Applications of brazing in the studying fields such as high-speed machining are very increasing in various industry fields. Therefore, applying to the fracture mechanics by numerical analysis method is very important to analyse the crack problem dissimilar materials in brazed interface. In this study, stress intensity factor(SIF) is analysed to investigate crack behavior on the crack tip of dissimilar materials in brazed interface such as a hardmetal and a HSS by two dimensional(2-D) BEM. Kelvin's solution was used as a fundamental solution in BEM analysis and stress extrapolation method was used to determine SIF.

• 한국생산제조학회지
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• 제18권5호
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• pp.498-506
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• 2009

An experimental study was performed to select cutting parameters for better quality-products in hard metals such as steels. Usually, a hard metal can be cut with a rotary cutting knife and the process provides a good cutting quality result. However, the cutting machine is much sensitive in cutting conditions because of its complicated mechanism. By this reason, careful processing conditions must be taken to improve the quality of the products. This experimental study for better quality products with a rotary cutting knife was carried out with two main factors; cutting speeds and cutting and pooling forces. A two-dimensional profile measuring instrument is used to evaluate its cutting faces and the effects of processing factors are analyzed by a commercial software.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.35-35
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• 2003

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2004년도 International Symposium on Powder Materials and Processing
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• pp.37-37
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• 2004

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2003년도 international symposium on advanced powder metallurgy
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• pp.54-55
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• 2003

• 자원리싸이클링
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• 제19권4호
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• pp.41-50
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• 2010

초경공구의 제조공정에서 발생하는 WC-Co 초경합금 슬러지로부터 텅스텐의 순환활용을 위한 기초연구가 수행되었다. 왕수를 사용하여 슬러지로부터 코발트를 침출함과 동시에 탄화텅스텐을 텅스텐산으로 변환시켜 회수하였다. 왕수농도, 반응온도와 시간, 광액농도 등이 코발트의 침출과 텅스텐산의 생성에 미치는 영향을 조사하였으며 최적조건을 도출하였다. 왕수농도 100 vol.%, 반응온도 $100^{\circ}C$, 반응시간 60분에서슬러지의 광액농도가 400 g/L에 도달할 때 까지 슬러지로부터 코발트의 완전한 추출이 이루어졌으나, 슬러지에 존재하는 모든 탄화텅스텐이 텅스텐산으로 완전히 전환되는 것은 광액농도가 150 g/L 이하일 때 이었다. 생성된 텅스텐산을 암모니아 용액에 용해함으로서 금속 불순물들을 불용성 잔사로 제거하는 것이 가능하였다. 증발결정 공정을 통하여 정제된 암모늄 텅스테이트 용액으로부터 99.85%의 순도를 가지는 암모늄 파라텅스테이트($(NH_4)_{10}{\cdot}H_2W_{12}O_{42}{\cdot}4H_2O$)를 얻을 수 있었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2005년도 춘계학술발표대회 및 제8회 신소재 심포지엄 논문개요집
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• pp.299-299
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• 2005