Journal of Failure Analysis and Prevention

, Volume 13, Issue 4, pp 451–462 | Cite as

Understanding the Effects of Mechanical and Laser Cut-Edges to Prevent Formability Ruptures During Automotive Manufacturing

Technical Article---Peer-Reviewed

Abstract

The cut-edge condition has an important influence on the formability capacity of high-strength steel (HSS) automotive structures. XF350 and DP600 under examination were observed to display a decreased level of formability in the surface regions because mechanical punched edge hole-flanging capacity is dependent on ductility and the surface quality of the cut-edge produced. Formability was observed to be highly dependent not purely based on the properties of the steel but also the cut-edge properties. Hole expansion capacity (HEC)-forming experiments were performed on flat circular plates with mechanical and laser-cut holes to investigate the fracture and forming limits of HSS. The HEC properties of the cut-edges were determined using mechanical and laser-cutting processes using various cutting process parameters in which certain edge types displayed decreases in edge ductility. It was found that, by altering the processing parameters during the cutting process, the edge quality can be improved, and this has a positive effect on the formability capacity of steel components.

Keywords

Forming HEC Hole expansion capacity Cut-edge forming 

Nomenclature

A

Elongation to failure

AHSS

Advanced high-strength steel

HEC

Hole expansion capacity

HSLA

High-strength low alloy

HSS

High-strength steel

Ra

Arithmetic mean of departures from the mean line

Rp

Maximum height of profile above the mean line

Rv

Maximum depth of profile below the mean line

wt

Weight

Notes

Acknowledgments

The present research was funded by a grant from the Engineering and Physical Sciences Research Council (EPSRC). The author wishes to acknowledge the support by Swansea University College of Engineering and The Engineering Centre for Manufacturing and Materials during the course of this research.

References

  1. 1.
    Johnson, W., Mamalis, A.G.: The perforation of circular plates with four-sided pyramidally headed square-section punches. Int. J. Mech. Sci. 20, 849–866 (1978)CrossRefGoogle Scholar
  2. 2.
    Wang, N.M., Wenner, M.L.: An analytical and experimental study of stretch flanging. Int. J. Mech. Sci. 16, 135–143 (1974)CrossRefGoogle Scholar
  3. 3.
    Kumagai, T., Saiki, H.: Deformation analysis of hole flanging with ironing of thick sheet metals. Met. Mater. 4(4), 711–714 (1999)CrossRefGoogle Scholar
  4. 4.
    Cho, Y.R., Chung, J.H., Ku, H.H., Kim, I.B.: Effect of controlled cooling on the formability of TS 590 MPa grade hot-rolled high strength steels. Met. Mater. 5(6), 571–578 (1999)CrossRefGoogle Scholar
  5. 5.
    Chitkara, N.R., Johnson, W.: Hole flanging and piercing of circular plate. Sheet Met. Ind. 51, 635–640 (1974)Google Scholar
  6. 6.
    Strijbos, G.H., Boesenkool, R.: Hole expansion in hot rolled steels. In: Proceedings of the 19th IDDRG Biennial Congress, Eger, 10–14 June 1996, pp. 459–466Google Scholar
  7. 7.
    Asnafi, N.: On stretch and shrink flanging of sheet aluminium by fluid forming. J. Mater. Process. Technol. 96, 198–214 (1999)CrossRefGoogle Scholar
  8. 8.
    Cho, Y.R., Chung, J.H., Ku, H.H., Kim, I.B.: A study on the stretch flangeability of hot-rolled high strength steel with ferrite–bainite duplex microstructures. Korean J. Mater. Res. 9(12), 1252–1262 (1999)Google Scholar
  9. 9.
    S. Keeler, Cutting sheet metal reduces edge formability. The Science of Forming Magazine, March (1999)Google Scholar
  10. 10.
    Stoughton, T.B.: A general forming limit criterion for sheet metal forming. Int. J. Mech. Sci. 42(1), 1–27 (2000)CrossRefGoogle Scholar
  11. 11.
    Carlsson, B., Larsson, J., Nilsson, T.: Dual phase steels for auto body design forming and welding aspects, pp. 1–14. SSAB Tunnplat AB, Borlange (1984)Google Scholar
  12. 12.
    Auto Steel Partnership Auto Steel Partnership http://www.asp.org/database/custom/hss_stampingDesignManual.pdf (2000). Accessed 16 May 2010
  13. 13.
    Sudo, M., Hashimoto, S., Kambe, S.: Niobium bearing ferrite–bainite high strength hot-rolled sheet steel with improved formability. Trans. Iron Steel Inst. Jpn. 23, 303–311 (1983)CrossRefGoogle Scholar
  14. 14.
    Cho, Y.R., Chung, J.H., Ku, H.H., Kim, I.B.: Effect of controlled cooling on the formability of TS 590 MPa grade hot-rolled high strength steels. Met. Mater. Korea 5, 571–578 (1999)CrossRefGoogle Scholar
  15. 15.
    Nagasaka, A., Sugimoto, K., Kobayashi, M., Shirasawa, H.: Effects of second phase morphology on warm stretch-flangeability of TRIPaided dual-phase sheet steels. Tetsu Hagane 84, 218–223 (1998)Google Scholar
  16. 16.
    Jiang, Z.H., Guan, Z.Z., Lian, J.S.: The relationship between ductility and material parameters for dual-phase steel. J. Mater. Sci. 28(7), 1814–1818 (1993)CrossRefGoogle Scholar
  17. 17.
    Jiang, Z., Lian, J., Chen, J.: Strain-hardening behaviour and its relationship to tensile mechanical properties of dual phase steel. Mater. Sci. Technol. 8(12), 1075–1081 (1992)CrossRefGoogle Scholar
  18. 18.
    Sugimoto, K., Sakaguchi, J., Iida, T., Kashima, T.: Stretch-flangeability of a high-strength TRIP type bainitic sheet steel. ISIJ Int. 40, 920–926 (2000)CrossRefGoogle Scholar

Copyright information

© ASM International 2013

Authors and Affiliations

  1. 1.Creation Engineering, Llynfi Enterprise CentreHeol-Ty-Gwyn Industrial EstateMaestegUK

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