Journal of Welding and Joining

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

DOI QR Code

Hardness Distribution and Microstructures of Electric Resistance Spot Welded 1GPa Grade Dual Phase Steel

1GPa급 DP강 전기저항점용접부의 경도분포와 미세조직의 상관관계

  • Na, Hye-Sung (Dept. of Material Science and Engineering, Pusan National University) ;
  • Kong, Jong-Pan (Dept. of Material Science and Engineering, Pusan National University) ;
  • Han, Tae-Kyo (POSCO Technical Research Laboratories) ;
  • Chin, Kwang-Geun (POSCO Technical Research Laboratories) ;
  • Kang, Chung-Yun (Dept. of Material Science and Engineering, Pusan National University)
  • Received : 2012.04.16
  • Accepted : 2012.04.30
  • Published : 2012.04.30
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, the effect of the welding current on the hardness characteristics and microstructure in the resistance spot welding of 1GPa grade cold-rolled DP steel was investigated, Also, correlation between the hardness and microstructure was discussed. In spite of the change in the welding current, the hardness distributions near weld was similar. the hardness in the HAZ and the fusion zone was higher than that of the base metal and the hardness in the fusion zone was variated with the location. Especially, the hardness of HAZ adjacent to the base metal showed maximum value, and softening zone in the base metal adjacent to HAZ was found. With the increasing of welding current, there were no difference in maximum hardness and average hardness in the fusion zone were, but the hardness of the softening zone reduced. The difference in the hardness in each location of weld due to grain size of prior austenite. The softening of the base metal occurred by tempering of the martensite.

Keywords

References

  1. J. Zrnik, I.Manuzic and S. V. Dobatkin : Recent progress in high strength low carbon steels, Metalurgija, 45, (2006), 323-331
  2. R. G. Davies : Influence of silicon and phosphorous on the mechanical properties of both ferrite and dual-phase steels, Metallurgical and Materials Transactions, 10A (1979), 113-118
  3. R. KUZIAK,R. KAWALLA, S. WAENGLER: Advanced high strength steels for automotive industry, ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, 2 (2008), 104-105
  4. Tae-Kyo Han, Kyoo-Young Lee and Jong-Sang Kim: Recent Developments and Weldability of Advanced High Strength Steels for Automotive Applications, J. KWS, 27 (2008), 131-132 (in Korean)
  5. P. Marashi, M. Pouranvari, S. Amirabdollahian, A. Abedi and M. Goodarzi, Microstructure and failure behavior of dissimilar resistance spot welds between low carbon galvanized & austenitic stainless steels, Mater Sci Eng A, 480 (2008), 175 https://doi.org/10.1016/j.msea.2007.07.007
  6. M. Pouranvaria, S. P. H. Marashib and D. S. Safanamab : Failure mode transition in AHSS resistance spot welds. Part II: Experimental investigation and model validation, Materials Science and Engineering A, 528 (2011), 8347-8349
  7. V. H. B. Hernandez, S. K. Panda , M. L. Kuntz and Y. Zhou : Nanoindentation and microstructure analysis of resistance spot welded dual phase steel, Materials Letters, 64 (2010), 207-210 https://doi.org/10.1016/j.matlet.2009.10.040
  8. V. H. B. Hernandez, M. L. Kuntz, M. I. Khan and Y. Zhou : Influence of microstructure and weld size on the mechanical behaviour of dissimilar AHSS resistance spot welds, Science and Technology of Welding & Joining, 13 (2008), 775
  9. M. I. Khan, M. L. Kuntz and Y. Zhou : Effects of weld microstructure on static and impact performance of resistance spot welded joints in advanced high strength steels, Science and Technology of Welding & Joining, 13 (2008), 301-302
  10. ISO standard : ISO 18278-2, Resistance welding Weldability Part 2: Alternative Procedures for the Assessment of Sheet Steels for Spot Welding, (2004)
  11. AWS D8.9-97 : Recommended Practices for Test Methods for Evaluating the Resistance Spot Welding Behavior of Automotive Sheet Steels, American Welding Society
  12. M. Li, D. Niebuhr, L. Meekisho and D. Atteridge : A Computational Model for the Prediction of Steel Hardenability, Metallurgical and Materials Transactions B, 29B(6) (2008), 661-672
  13. C. Maa, D. L. Chena, S. D. Bhole and G. Boudreau : Microstructure and fracture characteristics of spot-welded DP600 steel, Materials Science and Engineering A, 485 (2008), 338
  14. Jorge Otibo, Fabiana C.Nascimento, Paulo R.Mei, Lisandro P.Cardoso and Michael J.Kaufman : Materials Transactions. Vol.43, (2002) 916-919 https://doi.org/10.2320/matertrans.43.916