DOI QR코드

DOI QR Code

Evaluation on Temperature of FSW Zone of Magnesium Alloy using Experiment and FE Analysis

시험 및 유한요소법을 이용한 마그네슘 합금 마찰교반용접부 온도 특성 평가

  • Sun, Seung-Ju (Dept. of Railway System Engineering, University of Science and Technology) ;
  • Kim, Jung-Seok (Advanced Materials Research Team, Korea Railroad Research Institute) ;
  • Lee, Woo-Geun (Dept. of Railway System Engineering, University of Science and Technology)
  • 선승주 (과학기술연합대학원대학교 철도시스템공학과) ;
  • 김정석 (한국철도기술연구원) ;
  • 이우근 (과학기술연합대학원대학교 철도시스템공학과)
  • Received : 2016.06.22
  • Accepted : 2016.07.07
  • Published : 2016.07.31

Abstract

Friction Stir Welding (FSW) is a solid-state joining process involving the frictional heat between the materials and tools. The amount of heat conducted into the workpiece determines the quality of the welded zone. Excessive heat input is the cause of oxides and porosity defects, and insufficient heat input can cause problems, such as tunnel defects. Therefore, analyzing the temperature history and distribution at the center of the Friction Stir Welded zone is very important. In this study, the temperature distribution of the friction stir welding region of an AZ61 magnesium alloy was investigated. To achieve this goal, the temperature and metal flow was predicted using the finite element method. In FE analysis, the welding tool was simplified and the friction condition was optimized. Moreover, the temperature measuring test at the center of the welding region was performed to verify the FE results. In this study, the tool rotation speed was a more dominant factor than the welding speed. In addition, the predicted temperature at the center of the welding region showed good agreement with the measurement results within the error range of 5.4% - 7.7%.

마찰교반용접은 소재와 용접 툴 간의 마찰열에 의해 접합되는 고상접합 공정이다. 용접 시 발생하는 입열량에 따라 용접부의 건전성이 결정된다. 과도한 입열량은 산화물 및 기공결함의 원인이 되며, 불충분한 입열량은 터널결함 등의 문제점이 발생한다. 따라서 마찰교반용접부 중심에서의 온도 이력을 파악하는 것은 건전성을 판단하는 데 있어 매우 중요한 연구이다. 본 연구에서는 마그네슘 합금소재에 대한 마찰교반용접부의 온도분포 특성을 평가하였다. 이를 위해 유한요소해석을 통한 마찰교반용접부의 유동장 및 온도분포를 예측하였다. 유한요소해석을 위해 용접 툴 형상 간소화, 마찰 조건 선정 등 선행 해석을 수행하고 최적조건을 도출하였다. 또한, 해석모델의 검증을 위해 마그네슘 합금의 맞대기 마찰교반용접 시 용접부 중앙에서의 온도를 측정하였다. 유한요소해석 결과 마찰교반용접부의 온도에 영향을 미치는 주요변수의 기여도는 회전속도가 이송속도보다 더 높은 것으로 판단된다. 또한, 용접부 중심에서의 실측 온도와 유한요소해석 결과 사이에 5.4% - 7.7% 수준의 오차 내에서 잘 일치하였다.

Keywords

References

  1. H. Ohba, C. Ueda, K. Agatsuma,"Innovative Vehicle-the A-train," Hitachi Review, Vol. 50, No. 4, pp. 130-133, 2001.
  2. H. I. Dawood, K. S. Mohammed, M. Y. Rajab, "Advantages of the Green Solid State FSW over the Conventional GMAW Process" Advances in Materials Science and Engineering, Vol. 2014, pp. 1-10, 2014. DOI: http://dx.doi.org/10.1155/2014/105713
  3. C. M. Chen, R. Kovacevic,"Finite element modeling of friction stir welding-thermal and thermomechanical analysis," International Journal of Machine Tools and Manufacture, Vol. 43, No. 13, pp. 1319-1326, 2003. DOI: http://dx.doi.org/10.1016/S0890-6955(03)00158-5
  4. C. Hamilton, S. Dymek, A. Sommers,"A thermal model of firction stir welding in aluminum alloys," International journal of machine tools and manufacture, Vol. 48, No. 10, pp. 1120-1130, 2008. DOI: http://dx.doi.org/10.1016/j.ijmachtools.2008.02.001
  5. G. Buffa, A. Ducato, L. Fratini,"Numerical procedure for residual stresses prediction in friction stir welding," Finite Elements in Analysis and Design, Vol. 47, No. 4, pp. 470-476, 2011. DOI: http://dx.doi.org/10.1016/j.finel.2010.12.018
  6. S. W. Kang, B. S. Jang, H. C. Song,"Residual stresses analysis of friction stir welding using one-way FSI simulation," Journal of Mechanical Science and Technology, Vol. 29, No. 3, pp. 1111-1121, 2015. DOI: http://dx.doi.org/10.1007/s12206-015-0223-x
  7. Z. W. Chen, T. Pasang, Y. Qi,"Shear flow and formation of Nugget zone during friction stir welding of aluminium alloy 5083-O," Materials Science and Engineering: A, Vol.474, No.1, pp. 312-316, 2008. DOI: http://dx.doi.org/10.1016/j.msea.2007.05.074
  8. Y. H. Yau, A. Hussain, R. K. Lalwani, H. K. Chan, N. Hakimi,"Temperature distribution study during the friction stir welding process of Al2024-T3 aluminum alloy," International Journal of Minerals, Metallurgy and Materials, Vol. 20, No. 8, pp. 779-787, 2013. DOI: http://dx.doi.org/10.1007/s12613-013-0796-2

Cited by

  1. Evaluation of Mechanical Properties and Analysis of Microstructure of AZ61 Magnesium Alloy Butt Joints by Friction Stir Welding vol.19, pp.4, 2016, https://doi.org/10.7782/JKSR.2016.19.4.417