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Welding in the World

, Volume 52, Issue 11–12, pp 18–29 | Cite as

Prediction of Post Weld Hardness of Advanced High Strength Steels for Automotive Application using a Dedicated Carbon Equivalent Number

  • N. J. den Uijl
  • H. Nishibata
  • S. Smith
  • T. Okada
  • T. van der Veldt
  • M. Uchihara
  • K. Fukui
Research Supplement

Abstract

Weldability of advanced high strength steels in automotive manufacturing is a key issue. There are two important aspects to weldability: producing the welds and the quality of the welds. Producing the welds concerns the process to be used, possible addition of filler materials, the electrodes to be used, et cetera. Weld quality concerns the performance of the welds in a construction (e.g. strength and crash). With advanced high strength steels issues arise with increasing strength levels concerning the weld-quality. Traditionally carbon equivalent numbers are used to predict weldability. These traditional carbon equivalent numbers are not sufficient to predict post weld hardness of advanced high strength steels. Sumitomo Metal Industries and Corus cooperate to research weldability of advanced high strength steels. This paper concentrates on the influence of the chemical composition on weldability, as a first step to assess weldability of advanced high strength steels. This is done in two steps. First the traditional use of carbon equivalent numbers to predict weldability is explored. Literature is reviewed and possible issues with welding of advanced high strength steels are identified. Next the application of carbon equivalent numbers to predict post weld hardness for various welding processes (e.g. laser beam welding and resistance spot welding) is discussed. A wide range of steels was evaluated experimentally to determine the relationship between chemical composition and post weld hardness. The influence of welding processes expressed in terms of the cooling rates. The results are combined into simple models to predict post weld hardness of advanced high strength steel joints.

IIW-Thesaurus Keywords

Arc welding Carbon equivalent Composition Gas shielded arc welding Hardness Laser welding Mechanical properties Photon beam welding Plasma welding Radiation welding Reference lists Resistance spot welding Resistance welding Weldability 

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References

  1. [1]
    Gould J.E.: Weld process effects cracking — Hold time sensitivity and RSW of high strength steel, Welding Design and fabrication, 1999, 8, pp. 48–49.Google Scholar
  2. [2]
    Gould J.E., Khurana S.E., Li T.: Predictions of microstructures when welding automotive advanced high-strength steels, Welding Journal Research Supplement, 2006, 85, 5, pp. 111s–116s.Google Scholar
  3. [3]
    IIW Technical Report, IIW doc. IX-535–67, 1967.Google Scholar
  4. [4]
    Ito Y., Bessyo K.: Weldability formula of high strength steel related to Heat Affected Zone cracking, Journal of Japanese Welding Society, 1968, 37, 9, p. 938.Google Scholar
  5. [5]
    den Uijl N.J.: Modelling the influence of resistance spot welding on material properties, 3rd International Conference on Mathematical Modelling and Information Technologies in Welding and Related Processes, Kiev, 2006.Google Scholar
  6. [6]
    Easterling K.E.: Introduction to the physical metallurgy of welding — 2nd Ed., Butterworth Heinemann, 1992.Google Scholar
  7. [7]
    Hull D., Bacon D.J.: Introduction to dislocations, 3rd Edition, International Series on Materials Science and Technology, 1984, Volume 37, Pergamon Press.Google Scholar
  8. [8]
    Blondeau R., Maynier Ph., Dollet J.: Prévision de la dureté et de la résistance des aciers au carbone et faiblement alliés d’après leur structure et leur composition, Aciers spéciaux, no 27 pp. 9–16.Google Scholar
  9. [9]
    Chaillet J.M., Chevet F., Bocquet P., Dollet J.: Prediction of the microstructure and tensile properties of weld metal deposits, pp. 298–321.Google Scholar
  10. [10]
    Blondeau R., Maynier Ph., Dollet J.: Prévision de la dureté et de la résistance des aciers au carbone et faiblement alliés d’après leur structure et leur composition et leur traitement thermique, Revue métallurgie, Novembre 1975, pp. 759-769, Aciers spéciaux, no 27, pp. 9–16.Google Scholar
  11. [11]
    Yamauchi N., Taka T.: Spot weldability of high strength sheet steel, Sumitomo Metals, Technical Report of Sumitomo Metal Industries, Ltd., 1981, Vol. 33, No. 4, pp. 567–578 (in Japanese).Google Scholar
  12. [12]
    Ono M., Yoshitake A., Ohmura M.: Laser weldability of high strength steel sheets in fabrication of tailor welded blanks, Quarterly Journal of the Japan Welding Society, 2003, Vol. 21, No. 4, pp. 560–567 (in Japanese).CrossRefGoogle Scholar
  13. [13]
    Taka T., Yamamoto T.: The hardness of laser welded metal in steel sheets, Proceeding of 34th Material processing conference by Japan laser processing society, 1995-3, 1995, pp. 113–122 (in Japanese).Google Scholar
  14. [14]
    Mimer M., Svensson L-E., Johansson R.: Possibilities to improve fracture behaviour in resistance spot welds of EHSS and UHSS by process modifications, Proceedings of the 3rd International Seminar on Advances in Resistance Welding, Berlin, 2004.Google Scholar
  15. [15]
    den Uijl N.J.: Post Weld Heat Treatment of Advanced High Strength Steel for Automotive Joining, 8th International Seminar “Numerical Analysis of Weldability”, Seggau, 2006.Google Scholar
  16. [16]
    Nishi T., Saito T., Yamada A., Takahashi Y.: Spot weldability of high strength steel sheet for automobiles, Seitetsu Kenkyu, Technical report of Nippon Steel, 1982, No. 307, pp. 56–63 (in Japanese).Google Scholar
  17. [17]
    Westgate S.: The resistance spot welding of high and ultra-high strength steels, Proceedings of the 3rd International Seminar on Advances in Resistance Welding, Berlin, 2004.Google Scholar

Copyright information

© International Institute of Welding 2008

Authors and Affiliations

  • N. J. den Uijl
    • 1
  • H. Nishibata
    • 2
  • S. Smith
    • 1
  • T. Okada
    • 2
  • T. van der Veldt
    • 1
  • M. Uchihara
    • 2
  • K. Fukui
    • 3
  1. 1.Corus RD&TThe Netherlands
  2. 2.Sumitomo Metal IndustriesHyogoJapan
  3. 3.Sumitomo Metal IndustriesTokyoJapan

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