• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.1051-1054
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• 2002

Environmentally conscious machining and technology have been taking more and more important position in machining process. Since cutting fluid has some impact on environment, many researches are being carried out to minimize the use of cutting fluid. It can be Increased the environmental pollution through not using coolant any more or minimizing it. In this study, the cooling effects of cutting methods using the compressed cold air, dry cutting and cutting fluid will investigate in the blade machining. In order to examine the characteristics of cutting and tool in the environmentally conscious machining, this work investigates experimentally the degree of tool wear, cutting force and characteristics of surface roughness in relation to machining conditions and cooling methods.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.956-961
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• 2003

Recently, environmental pollution has become a significant problem in industry and many researches have been investigated in order to preserve the environment. Environmentally conscious machining and technology have more and more important position in machining process. In the milling process, the cutting fluid has greatly bad influence on the environment. In this study, the machining of blade parts(12Cr steel) using the cutting fluid, compressed cold air and oil mist etc., also, the productivity and the surface topography was improved by using new end-mil tool considering tool material and shape.

• 동력기계공학회지
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• 제16권1호
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• pp.58-64
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• 2012

Power plant boiler is one of the most important utilities providing steam to turbine in thermal power plant. It is composed of thousands of boiler tubes for high efficient heat transfer. Boiler tube material is used in such high temperature and pressure as $540^{\circ}C$, $170kg/mm^2$. The boiler tube material is needed to resist corrosion damage, creep damage and fatigue damage. 2.25%Cr-1Mo steel is used for conventional boiler tubes. In these days steam temperature and pressure of the power plant became higher for high plant efficiency. So, the material property of boiler tube must be upgraded to meet the plant property. Several boiler tube material was developed to meet such condition. X20CrMoV12.1 steel is also developed in early 1980's and used for superheater and reheater tubes in supercritical boilers. The material has martensitic structure, which is difficult to evaluate the material degradation. Boiler tube material at severe condition was tested to evaluate long term and short term degradation and creep. Through long term and high temperature degradation test, lath structure was decreased and recrystallization has been proceeded by sub-crystal. And in this research the effect of temperature and stress on boiler tube characteristic,for example, deformation by creep was changed rapidly at relatively high temperature and stress because creep was affected easily by temperature and stress.

• 한국산학기술학회논문지
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• 제18권9호
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• pp.61-67
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• 2017

프레스금형 제작 시 사용목적에 맞는 적합한 소재선택과 빠른 가공방법에 대한 연구는 금형제작시간을 줄이고 금형원가를 절감하는데 절대적으로 필요한 연구분야이다. 특히 장수명 프레스금형을 개발하기 위해선 열에 대한 고찰이 반드시 이루어져야 한다. 일반적으로 프레스금형의 주요부품 소재로는 Cr, W계 저합금 공구강, 고탄소 고크롬강, 고속도강 등 냉간 금형용 합금공구강이 많이 쓰이고 있다. 프레스금형부품을 가공하는 데는 주로 공작기계와 와이어 컷 방전가공을 사용하고 있다. 가공공정에 따라 금형부품의 가공시간 및 수명이 많은 차이가 난다. 밀링가공과 연삭가공으로 제작된 부품의 경우 제작시간과 비용은 많이 드는데 비해 금형의 수명이 길고 밀링가공과 와이어 컷 방전가공을 사용하면 제작시간과 비용은 절감되는 반면 금형수명은 줄어드는 현상이 나타난다. 따라서 본 연구에선 가공시간과 비용이 절감되는 가공방법으로 열처리를 사용하여 금형의 사용수명을 향상시키는 방법에 대해 고찰하고자 한다. 밀링가공-연삭가공, 밀링가공-와이어 컷 방전가공, 밀링가공-와이어 컷-고온템퍼링, 3가지 가공방법으로 시편을 제작하여 가공표면과 중심부를 SEM, EDS분석 및 표면조도분석으로 문제점을 고찰하였고 밀링가공-와이어 컷 방전가공-고온템퍼링의 가공방법으로 밀링가공-연삭가공과 동일한 금형의 수명을 만드는 방법을 도출하였다.