Transactions of Materials Processing (소성∙가공)

The Korean Society for Technology of Plasticity and materials processing (한국소성∙가공학회)
권호 표지
DOI QR코드

DOI QR Code

Quantitative Evaluation of Scratch Related Tool Life for Stamping of UHSS Using Pin-on-Flat Surface Test

Pin-on-Flat Surface Test를 이용한 초고장력강판 스탬핑 금형의 정량적 스크래치 수명평가

  • 최홍석 (부산대학교 기계공학부) ;
  • 김성귀 (부산대학교 부품소재산학협력연구소 그린수송시스템전공) ;
  • 김병민 (부산대학교 기계공학부) ;
  • 고대철
  • Received : 2012.11.12
  • Accepted : 2013.02.06
  • Published : 2013.04.01
Download PDF
⟨ Previous Next ⟩

Abstract

When stamping ultra-high-strength steel (UHSS), the phenomenon of galling, which corresponds to a transfer of material from the sheet to the tool surface, occurs because of the high contact pressure between tool and workpiece. Galling leads to increased friction, unstable interface conditions, scratches on the sheet and the tool surfaces and, eventually, premature tool surface failures. Therefore, a simple and accurate evaluation method for tool scratching is necessary for the selection of tool material and coating, as well as for a better optimization of process conditions such as blank holder force and die radius. In this study, the pin-on-disc (PODT) and pin-on-flat surface (POFST) tests are conducted to quantitatively evaluate scratch-related tool life for stamping of UHSS. The variation of the friction coefficient is used as an indicator of scratch resulted from galling. The U-channel ironing test (UCIT) is performed in order to validate the results of the friction tests. This study shows that the POFST test provides a good quantitative estimation of tool life based on the occurrence of scratch.

Keywords

References

  1. C. H. Suh, H. D. Shin, Y. C. Jung, C. D. Park, Y. H. Lim, Y. S. Kim, 2009, A Study on the Forming Process of Stair Type Side Sill for Automobile using DP780, Trans. Mater. Process., Vol. 18, No. 8, pp. 601-606. https://doi.org/10.5228/KSPP.2009.18.8.601
  2. D. H. Lee, T. J. Kim, J. D. Lim, H. J. Lim, 2009, Development of High Strength Steel Body by Hot Stamping, Trans. Mater. Process., Vol. 18, No. 4, pp. 304-309. https://doi.org/10.5228/KSPP.2009.18.4.304
  3. Z. Wang, H. Kubota, D. Xue, Q. Lin, M. Okamura, 2006, Galling Behavior in Square Cup Drawing of High-tensile-strength Steel, J. Jpn. Soc. Technol. Plast., Vol. 47, No. 549, pp. 988-992. https://doi.org/10.9773/sosei.47.988
  4. M. Nilsson, M. Olsson, 2011, Tribological Testing of Some Potential PVD and CVD Coatings for Steel Wire Drawing Dies, Wear, Vol. 273, No. 1, pp. 55-59. https://doi.org/10.1016/j.wear.2011.06.020
  5. A. Gaard, P. Krakhmalev, J. Bergström, 2009, Wear Mechanism in Galling: Cold Work Tool Materials Sliding Against High-strength Carbon Steel Sheets, Tribol. Lett., Vol. 33, No. 1, pp. 45-53. https://doi.org/10.1007/s11249-008-9390-6
  6. B. Podgornik, S. Hogmark, O. Sandberg, 2004, Influence of Surface Roughness and Coating Type on the Galling Properties of Coated Forming Tool Steel, Surf. Coat. Technol., Vol. 184, No. 2-3, pp. 338-348. https://doi.org/10.1016/j.surfcoat.2003.11.002
  7. J. Eriksson, M. Olsson, 2011, Tribological Testing of Commercial CrN, (Ti, Al)N and CrC/C PVD Coatings: Evaluation of Galling and Wear Characteristics Against Different High Strength Steels, Surf. Coat. Technol., Vol. 205, No. 16, pp. 4045-4051. https://doi.org/10.1016/j.surfcoat.2011.02.053
  8. A. C. Fischer-Cripps, 2001, Nanoindentation, Springer-Verlag, New York, Inc., pp. 1-7.
  9. E. Schedin, 1994, Galling Mechanisms in Sheet Forming Operations, Wear, Vol. 179, No. 1-2, pp. 123-128. https://doi.org/10.1016/0043-1648(94)90229-1

Cited by

  1. Indirect Prediction of Surface Damage for a Press Die with Wear Characteristics and Finite Element Stamping Analysis vol.23, pp.1, 2014, https://doi.org/10.5228/KSTP.2014.23.1.29
  2. Study on Spring-Back Effect according to Roll Gap and Forming Velocity of Roll Forming Process vol.33, pp.6, 2016, https://doi.org/10.7736/KSPE.2016.33.6.477