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High temperature flow behavior of extruded ZK60A alloy
H. Lee(이한주),M. Kawasaki(가와사키메구미),K. J. Jung(정기호),G. A. Lee(이근안),B. Ahn(안병민) 한국소성가공학회 2013 한국소성가공학회 학술대회 논문집 Vol.2013 No.5
Tensile tests were conducted on a continuous-casted ZK 60A after extrusion at a range of strain rates at temperatures from 473 to 623K. It is shown that the alloy exhibits a quasi-superplastic behavior with a maximum recorded elongation of ~250% at 523K when testing with an initial strain rate of 1.0 x 10<SUP>-5</SUP> s<SUP>-l</SUP>. The experiments give a strain rate sensitivity of ~0.3-0.4 and an activation energy of ~108 kJ/mol. From the investigation, a high-temperature flow of the ZK 60A is controlled by a dislocation viscous glide process.
등방압 적용 Conformal Cooling Channel Core 금형기술에 대한 기초 연구
이성희(S.H. Lee),차백순(B.S. Cha),윤길상(G.S. Yoon),고영배(Y.B. Ko),박훈재(H.J. Park),최태훈(T.H. Choi),이근안(G.A. Lee) 한국소성가공학회 2010 한국소성가공학회 학술대회 논문집 Vol.2010 No.10
A basic research on isostatic technology for advancing the material property of direct metal tool ing core was performed in this study. The advantages of direct metal tool ing core are well known for the reduction of cycle time and the acquirement of high quality product in injection mold process. However there are some problems in density of structure, such as micro scale void. Therefore this research focused on the feasibility study for the application of isostatic process on mold making aspect. Direct tooled tensile specimen and inject ion mold core were prepared to invest i gat e the effect of isostatic process on dimensional change, hardness variation and tooling characteristics. It was shown that dimensional variation ratio was smaller than hardness variation ratio and there was no significant difference in machining result.
김건희(G. H. Kim),윤길상(G. S. Yoon),김종덕(J. D. Kim),이정원(J. W. Lee),이근안(G. A. Lee) 한국소성가공학회 2011 한국소성가공학회 학술대회 논문집 Vol.2011 No.5
In this study, the low temperature micro cutting process was proposed. In macro cutting fields, the cryogenic cutting process has been applied to cut the refractory metal but, the serious problems may be generated in micro cutting fields by the cryogenic environment. However, if the proper low temperature is applied to micro cutting area, the cooling effect of cutting heat is expected. Such effect can make the reduction of tool wear and burr formation. For verifying this possibility, the micro cutting experiments at low temperature was performed and tool wear images and SEM images were analyzed.
이형욱(H. W. Lee),이근안(G. A. Lee),최석우(S. Choi),박홍균(H. K. Park),배성민(S. M. Bae) 한국정밀공학회 2006 한국정밀공학회 학술발표대회 논문집 Vol.2006 No.5월
Many data mining techniques have been proved useful in revealing important patterns from large data sets. Especially, data mining techniques play an important role in a customer data analysis in a financial industry and an electronic commerce. Also, there are many data mining related research papers in a semiconductor industry and an automotive industry. In addition, data mining techniques are applied to the bioinformatics area. To satisfy customers’ various requirements, each industry should develop new processes with more accurate production criteria. Also, they spend more money to guarantee their products’ quality. In this manner, we apply data mining techniques to the production-related data such as a test data, a field claim data, and POP (point of production) data in the automotive parts industry. Data collection and transformation techniques should be applied to enhance the analysis results. Also, we classify various types of manufacturing processes and proposed an analysis scheme according to the type of manufacturing process. As a result, we could find inter- or intraprocess relationships and critical features to monitor the current status of the each process. Finally, it helps an industry to raise their profit and reduce their failure cost.