Journal of Welding and Joining

The Korean Welding and Joining Society (대한용접접합학회)
권호 표지
DOI QR코드

DOI QR Code

Analysis of Microstructure for Resistance Spot Welded TRIP Steels using Atomic Force Microscope

원자력간 현미경을 이용한 TRIP강 저항 점용접부의 미세조직 분석에 관한 연구

  • Choi, Chul Young (School of Materials Science and Engineering, Pusan National University) ;
  • Ji, ChangWook (School of Materials Science and Engineering, Pusan National University) ;
  • Nam, Dae-Geun (Korea Institute of Industrial Technology (KITECH)) ;
  • Jang, Jaeho (School of Materials Science and Engineering, Pusan National University) ;
  • Kim, Soon Kook (Dept. of Advanced Material Engineering, Dong-Eui University) ;
  • Park, Yeong-Do (Dept. of Advanced Material Engineering, Dong-Eui University)
  • Received : 2013.02.10
  • Accepted : 2013.02.22
  • Published : 2013.02.28
Download PDF
⟨ Previous Next ⟩

Abstract

The spot welds of Transformation Induced Plasticity (TRIP) steels are prone to interfacial failure and narrow welding current range. Hard microstructures in weld metal and heat affected zone arenormally considered as one of the main reason to accelerate the interfacial failure mode. There fore, detailed observation of weld microstructure for TRIP steels should be made to ensure better weld quality. However, it is difficult to characterize the microstructure, which has similar color, size, and shape using the optical or electron microscopy. The atomic force microscope (AFM) can help to analyze microstructure by using different energy levels for different surface roughness. In this study, the microstructures of resistance spot welds for AHSS are analyzed by using AFM with measuring the differences in average surface roughness. It has been possible to identify the different phases and their topographic characteristics and to study their morphology using atomic force microscopy in resistance spot weld TRIP steels. The systematic topographic study for each region of weldments confirmed the presence of different microstructures with height of 350nm for martensite, 250nm for bainite, and 150nm for ferrite, respectively.

Keywords

References

  1. S. S. Park, Y. M. Choi, D. G. Nam, Y. S. Kim, J. H. Yu and Y. D. Park, Journal of KWJS, 26-6 (2008), 625
  2. S. S. Park, Y. D. Park, K. H. Kim, Y. M. Choi, Y. M. Rhym and N. H. Kang, Journal of KWJS. 26-2 (2008), 177
  3. K. C. Kim, J. H. Cha and H. S. Park, Journal of Materials Research. 14-4 (2004), 239
  4. D. J. Radakovic and M. Tumuluru, American Welding Journal. 87(2008), 96
  5. C. Y. Choi, I. B. Kim, Y. D. Kim and Y. D. Park, Kor. J. Met. Mater. 50-2 (2012), 136
  6. C. Y. Choi, J. K. Kim, J. K. Hong, J. T. Yeom and Y. D. Park, J. P. Journal of KPMI. 18-1 (2011), 64
  7. C. H. Lee, K. H. Lee, J. H. Yoon and Y. E. Shin, Journal. KWJS. 26-1 (2008), 56
  8. S. M. An, T. K. Yim, K. S. Lee, J. H. Kim, E. Y. Kim and K. W. Park, Kor. J. Met. Mater. 49-4 (2011)
  9. K. C. Chung, Y. K. Kim and C. J. Choi, Kor. J. Met. Mater. 48-4 (2010), 320
  10. C. Y. Choi, I. B. Kim, Y. D. Kim and Y. D. Park, Kor. J. Met. Mater. 50-2 (2012), 136 https://doi.org/10.3365/KJMM.2012.50.2.136
  11. T. H. Kim, H. S. Park, Y. S. Lee, S. H. Rhee, Proc. J. KSAE. 2 (2003), 1239
  12. B. Girvin, W. Peterson and J. Gould, American Iron and Steel Institute. 27 (2007), A10
  13. F. S. Lepera, Metallography. 12 (1979), 263 https://doi.org/10.1016/0026-0800(79)90041-7
  14. M. Tumuluru, American Welding Journal. 86-6 (2007), 161s
  15. T. R. Yanez, Y. Houbaert, A. Mertens, Materials Characterization. 47 (2001), 93 https://doi.org/10.1016/S1044-5803(01)00157-7