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용접 와이어를 이용한 5000 계열 알루미늄 레이저 용접의 용접부 성형특성 평가에 대한 연구
박영환(Young Whan Park),안재훈(Jae Hoon An),김동윤(Dong Yun Kim) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
In this study, aluminum laser welding of AA5182 with AA5356 filler wire was performed with 4㎾ Nd:YAG Laser. In order to determine the feasibility to apply 5000 series aluminum alloy to car body, the formability was investigated through Erichsen test according to laser power, welding speed and wire feed rate. Fracture after Erichsen test was occurred perpendicular to the weld line if the Erichsen ratio was over 0.75 and fracture was parallel to the weld line otherwise. The Erichsen ratio value of 0.75 could be criterion to evaluate formability.
Formability evaluation of dimple forming process based on numerical and experimental approach
Heo, Seong-Chan,Seo, Yung-Ho,Ku, Tae-Wan,Kang, Beom-Soo 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.2
Exhaust gas recirculation (EGR) cooler consists of a number of heat transfer tubes that have relatively larger net area than that of flat type tubes. The surface of the tubes is made up with lots of grooves and protrusions for enlarging the net heat transfer area. Most tubes are manufactured through forming processes, such as bending, spinning, roll forming, stamping and so on. Therefore, a series of fracture or detect can occur during the various forming processes. In this study, the manufacturing process of a dimple-type rectangular heat transfer tube used for an EGR cooler system is investigated based on the numerical simulation and the experimental approach. A prototype of the tube is designed and modified to a newly designed tube considering the conservation of the net heat transfer area based on the numerical and analytical approach. Formability evaluation of the tube sheet is carried out by using forming limit curves based on the plastic instability conditions. Strain- and stress-based forming limit curves are utilized to ensure the strain path independence. The newly designed tube having a number of dimples on the both sides are manufactured by the press forming process. Thickness distributions for the principal cross-sections are observed from both the simulation and the experiment and compared each other. From the results, it is confirmed that the forming process is robust to manufacture the dimple type rectangular tubes with the comparison of thickness, and application of the forming limit curves.
MULTY-STAGE COLD FORGING PROCESS OPTIMIZATION OF EPB SPINDLE NUT BY FORMABILITY EVALUATION
Young Ho Seo 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.1
Forged parts made of cold heading quality wire materials are used for automotive brake systems. In general, forged parts are limited in weight reduction due to strict configuration management, and thus cost reduction in the manufacturing process is a significant topic. In order to reduce the material cost, heat treatment-abbreviated material was applied and the formability of the processes was verified by stress triaxiality diagram. In this process, the limitations of the standard ductile fracture formula were verified. In addition, the causes of shape fixation and die life degradation were analyzed using numerical simulation. As a result, the process cost of EPB spindle parts has been minimized by redesigning the process, and changing the product shape and the die material.