자동차 조향장치 부품 요크의 온간 밀폐 단조 적용을 위한 금형 응력 저감 설계 및 온간 단조품의 기계적 특성 분석 = Die Stress Reduction Design and Mechanical Properties Analysis of Warm Forging Process for the Application of Warm-Closed Forging of Automative Steering Unit Yoke

다국어 초록 (Multilingual Abstract)

In this study, finite element analyses were performed by applying a stress ring and split die design to relieve the tensile stress acting on the die due to high surface pressure during warm-closed forging. The applied material was a yield-ratio-control-steel (YRCS). It was used without quenching or tempering after forging. In the case of stress rings design, the number of stress rings and the tolerance for shrink fit were different. Vertical and horizontal splits were applied for insert die split design. Case 5 die with three stress rings, 0.2 % shrink fit tolerance, and vertical split was selected as an effective die design for tensile stress reduction. Based on die stress reduction analyses, Case 5 die for warm-closed forging was produced and smooth forgeability was secured, making it possible to manufacture forging product of yoke with the required geometry. In addition, controlled cooling using warm forging heat was applied to secure mechanical properties of yokes. When oil cooling was used for direct controlled cooling after warm-closed forging, a relatively uniform Rockwell hardness distribution and high mechanical properties could be obtained.

참고문헌 (Reference)

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