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국부가열을 통한 DP980 소재의 온간 V굽힘에서 발생하는 조직 및 경도 변화에 대한 연구
황준선(J. S. Hwang),이은호(E. H. Lee),이창환(C. W. Lee),양동열(D. Y. Yang),양우호(W. H. Yang) 한국소성가공학회 2012 한국소성가공학회 학술대회 논문집 Vol.2012 No.10
High strength steel is widely used to meet the needs of lightweight vehicle part. Because high strength steel has high strength, large amount of spring back after forming was generated. Near Infrared Ray (NIR) heater is one of the method to solve that problem. In this study, the microstructure and hardness of dual phase steel was measured in the V-bending test using NIR heater to check the degree of softening after local heating. To verify the hardness results of warm, v-bending, we compare the hardness of cold v-bended specimen with the hardness of heated and quenched specimen without bending And the tensile test according to heating time with fixed temperature of 600℃ was conducted to suggest the limit heating time.
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.