Transactions of Materials Processing (소성∙가공)

The Korean Society for Technology of Plasticity and materials processing (한국소성∙가공학회)
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Computation of High Temperature Friction Coefficient of SCM435 Steel

SCM435 강의 고온마찰계수 계산

  • 성중의 (중앙대학교 기계공학부) ;
  • 조상흠 (중앙대학교 기계공학부) ;
  • 이형직 (POSCO 기술연구소 선재연구그룹) ;
  • 이영석 (중앙대학교 기계공학부)
  • Received : 2011.03.10
  • Accepted : 2011.05.20
  • Published : 2011.06.01
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Abstract

In this study, an approach designed to compute high temperature friction coefficients for SCM 435 steel through a pilot hot rolling test and a finite element analysis, is proposed. Single pass pilot hot flat rolling tests with reduction ratios varying from 20 to 40% were carried out at temperatures ranging from 900 to $1200^{\circ}C$. In the proposed approach, the friction coefficient is calculated by comparing the measured strip spread and the roll force with the simulation results. This study showed that the temperature and reduction ratio had a significant influence on the friction coefficient. As both material temperature and reduction ratio become higher, the friction coefficient increases monotonically. This finding is not in agreement with the Ekelund model, which is widely used in the analysis of the hot rolling process. In the present work, the friction coefficient at a reduction ratio of 40% was found to be 1.2 times greater than that at a reduction of 30%. This higher friction coefficient means that an increment of the roll thrust force is expected at the next stand. Therefore, a roll pass designer must understand this phenomenon in order to adjust the reduction ratio at the stands while keeping the driving power, the roll housing structure and the work roll strength within the allowable range.

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References

  1. C. H. Kim, 1996, Tribology in Hot Rolling, J. Kor. Soc. Tribol. Lubr. Eng., Vol. 12, No. 3, pp. 1-5.
  2. Y. J. Liu, A.K. Tieu, D. D. Wang, W.Y.D. Yuen, 2001, Friction measurement in cold rolling, J. Mater. Process. Technol., Vol. 111, pp. 142-145. https://doi.org/10.1016/S0924-0136(01)00541-6
  3. J. Jeswiet, 1998, A comparison of friction coefficient in cold rolling, J. Mater. Process. Technol., pp. 239-244.
  4. H. Ford, Advanced Mechanics of Materials, Longmans, Green and Co., London, 1963.
  5. UNDERWOOD, L. R., 1952, The rolling of Metals, Vol. 1.
  6. B. Hum, H. W. Colquhoun, J. G. Lenard, 1996, Measurements of friction during hot rolling of aluminum strip, J. Mater. Process. Technol., Vol. 60, pp. 331-338. https://doi.org/10.1016/0924-0136(96)02350-3
  7. K. H. Jung, H. W. Lee, Y. T. Im, 2009, Numerical prediction of austenite grain size in a bar rolling process using an evolution model based on a hot compression test, J. Mater. Sci. Eng., Vol. A519, pp. 94-104.
  8. L. M. Galantucci, L. Tricarico, 1999, Thermomechanical simulation of a rolling process with an FEM approach, J. Mater. Process. Technol., pp. 494-501.
  9. J. G. Lenard, 1991, The effect of temperature on the coefficient of friction in flat rolling, CIRP Ann. Manuf. Technol. , Vol. 40(1) , pp. 223-226. https://doi.org/10.1016/S0007-8506(07)61973-8
  10. Wusatoski, 1960, Fundamentals of Rolling, Oxford University Press. London.