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마그네슘 합금 판재의 외부 열원을 사용한 굽힘공정의 스프링백에 관한 연구
이은호(E. H. LEE),이창환(C. W. LEE),양동열(D. Y. YANG) 한국소성가공학회 2011 한국소성가공학회 학술대회 논문집 Vol.2011 No.10
In industry areas, magnesium alloy sheets have been consistently researched due to its outstanding mechanical property. However formability of the magnesium alloy sheets is highly limited in the room temperature due to its hexagonal close packed(HCP) micro structures. Also it is hard to predict the characteristic of the springback in forming of the magnesium alloy sheet. In this study, the three-point bending tests with an external heat source were conducted in some temperature conditions. The external heat source heated only areas where the plastic deformation occurred. The springback decreased as much as the whole heating test in a heat chamber. And it is found out that the springback decreased in local heating condition after the room temperature forming.
근적외선 국부가열에 의한 난성형 판재 성형성 및 스프링백 분석
이은호(E. H. LEE),황준선(J. S. HWANG),이창환(C. W. LEE),양동열(D. Y. YANG) 한국소성가공학회 2013 한국소성가공학회 학술대회 논문집 Vol.2013 No.5
Ever since the environmental concerns became a global issue, industries have paid closer attention to lightweight materials that are higher in strength and lower in density. Lightweight materials are apt for high fuel efficiency, but their low formability and high degree of springback have been the obstacles to their widespread use. Consequently, these materials are called hard-to-form materials. In order to increase the formability of hard-to-form materials and to reduce the degree of springback, there has been much research on warm forming process. However, increasing the temperature of the whole die or the material will result in great energy consumption. As a solution to such drawbacks, this research was conducted with local heating method which heats the area where plastic deformation occurs. After the AZ31, Ti Gr2, Ti Gr5 sheet metals were locally heated by NIR local heating devices, V-bending test was carried out in various temperature condition in order to analyze formability and springbacks. The results of the experiment confirmed the applicability of the NIR local heating method.
고효율 근적외선 가열장치를 사용한 온간성형에서 DP980 소재의 스프링백 분석
이은호(E. H. LEE),황준선(J. S. HWANG),이창환(C. W. LEE),양동열(D. Y. YANG),양우호(W. H. YANG) 한국소성가공학회 2012 한국소성가공학회 학술대회 논문집 Vol.2012 No.10
In recent years, increasing attention for environment and safety have made high-strength steel be one of the most important materials. Especially, automobile industry has given much attention to high-strength steel sheets in order to obtain high fuel efficiency and safety for passengers. In high-strength steel sheet forming, however, Large springback after unloading has been a obstacle to expansion of usage. To reduce springback of high-strength steel sheet, warm forming has been consistently researched, but increasing temperature whole die or material consumes huge energy. Therefore in this research, DP980 sheet metals were heated only areas where plastic deformation occurs by NIR local heating devices. After that, V-bending and 2D-draw bending were carried out to Analysis springback. Also evaluation of possibility of NIR local heating was conducted through analysis of springback in V-bending and 2D-draw bending.
외부열원을 사용한 마그네슘 합금 판재의 굽힘방식에 따른 성형특성 및 스프링백 연구
이은호(E. H. LEE),이창환(C. W. LEE),양동열(D. Y. YANG) 한국소성가공학회 2012 한국소성가공학회 학술대회 논문집 Vol.2012 No.5
In industry areas, magnesium alloy sheets have been consistently researched due to its outstanding mechanical property. However formability of the magnesium alloy sheet is very low in the room temperature due to its hexagonal close packed(HCP) micro structures. Also it is hard to predict the characteristic of the springback in forming of the magnesium alloy sheet. In this study, Unconstrained bending test, V-bending test and Air bending test with an external heat source were conducted in some temperature conditions. The external heat source heated only areas where plastic deformation occurred. And in all the tests as temperature increased, the forming load decreased and the springback decreased. According to the results, local heating with an external heat source have the ability to increase the formability and decrease the springback.