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Study of the influence of material and geometry on the anisotropy of dimensional change on sintering of Powder Metallurgy parts

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Abstract

In the conventional press and sinter process, dimensional change on sintering determines the precision of the final parts, providing that a good dimensional precision of green parts is ensured. Anisotropic dimensional change on sintering may be detrimental to the precision of Powder Metallurgy (PM) parts, and it should be considered in the design step. The effect of material and geometry on the anisotropic dimensional change is studied in this work. Four different iron alloys and five different geometries were considered. Dimensions were measured both on green and on sintered parts and the anisotropy of dimensional change was evaluated and correlated to the material and geometry. The effect of neglecting anisotropy in the design step was investigated, in terms of dimensional tolerances, which can be obtained with different process capabilities. A model to describe the effect of material and geometry on the anisotropic dimensional change is also being developed.

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Abbreviations

Dext :

dimensional change in the external diameter normalized by the isotropic dimensional change

Dint :

dimensional change in the internal diameter normalized by the isotropic dimensional change

dN :

nominal dimension [mm]

dg :

dimension of the green part [mm]

ds :

dimension of the sintered part [mm]

e:

process capability error

H:

dimensional change in height normalized by the isotropic dimensional change

h:

height of the part (disks - rings) [mm]

hg :

height of the green part (disks - rings) [mm]

hN :

nominal height [mm]

hs :

height of the sintered part (disks - rings) [mm]

K:

anisotropy parameter

lg :

dimension in the green state [mm]

R:

ratio between the internal and the external diameter in the green parts

t:

wall thickness of the rings [mm]

Vg :

volume of the green part (disks - rings) [mm3]

Vs :

volume of the sintered part (disks - rings) [mm3]

α :

geometrical parameter relating the dimensional changes in the internal and external diameters

γ :

geometrical parameter relating R and α

ΔV/Vg :

volume change

ε d :

actual dimensional change

ε h :

dimensional change in height

ε iso :

isotropic dimensional change

ε ref :

dimensional change relevant to a known reference geometry

ε ϕ :

dimensional change in the external diameter for disks

ε ϕ ext :

dimensional change in the external diameter for rings

ε ϕ int :

dimensional change in the internal diameter for rings

ϕ:

external diameter of the disks [mm]

References

  1. German, R. M., “Sintering Theory and Practice,” John Wiley and Sons, pp. 67–304, 1996.

    Google Scholar 

  2. Cristofolini, I., Menapace, C., Cazzolli, M., Rao, A., Pahl, W., and Molinari, A., “The Effect of Anisotropic Dimensional Change on the Precision of Steel Parts Produced by Powder Metallurgy,” Journal of Materials Processing Technology, Vol. 212, No. 7, pp. 1513–1519, 2012.

    Article  Google Scholar 

  3. Cristofolini, I., Pilla, M., Larsson, M., and Molinari, A., “A Doe Analysis of Dimensional Change on Sintering of a 3% Cr-0.5% Mo-X% C Steel and Its Effect on Dimensional and Geometric Precision,” Powder Metallurgy Progress, Vol. 12, No. 3, pp. 127–143, 2012.

    Google Scholar 

  4. Cristofolini, I., Pilla, M., Rao, A., Libardi, S., and Molinari, A., “Dimensional and Geometrical Precision of Powder Metallurgy Parts Sintered and Sinterhardened at High Temperature,” Int. J. Precis. Eng. Manuf., Vol. 14, No. 10, pp. 1735–1742, 2013.

    Article  Google Scholar 

  5. Cristofolini, I., Selber, F., Menapace, C., Pilla, M., Molinari, A., and Libardi, S., “Anisotropy of Dimensional Variation and its Effect on Precision of Sintered Parts,” Proc. of Euro PM 2012 Congress & Exhibition, 2012.

    Google Scholar 

  6. Cristofolini, I., Pilla, M., Molinari, A., Menapace, C., and Larsson, M., “A DOE Investigation on Anisotropic Dimensional Change on Fe-C-Cu Sintering,” International Journal of Powder Metallurgy, Vol. 48, No. 4, pp. 37–43, 2012.

    Google Scholar 

  7. Wanibe, Y., Yokoyama, H., and Itoh, T., “Expansion during Liquid Phase Sintering of Iron-Copper Compacts,” Powder Metallurgy, Vol. 33, No. 1, pp. 65–69, 1990.

    Article  Google Scholar 

  8. Griffo, A., Ko, J., and German, R., “Critical Assessment of Variables Affecting the Dimensional Behavior in Sintered Iron-Copper-Carbon Alloys,” Advances in Powder Metallurgy and Particulate Materials, Vol. 3, pp. 221–236, 1994.

    Google Scholar 

  9. Raman, R., Zahrah, T., Weaver, T., and German, R., “Predicting Dimensional Change during Sintering of FC0208 Parts,” Advances in Powder Metallurgy and Particulate Materials, Vol. 1, No. 3, pp. 115–122, 1999.

    Google Scholar 

  10. Danninger, H., “Sintering of Mo Alloyed PM Steels Prepared from Elemental Powders. II. Mo Homogenization and Dimensional Behaviour,” Powder Metallurgy International, Vol. 24, No. 3, pp. 163–168, 1992.

    MathSciNet  Google Scholar 

  11. Zavaliangos, A. and Bouvard, D., “Numerical Simulation of Anisotropy in Sintering due to Prior Compaction,” International Journal of Powder Metallurgy, Vol. 36, No. 7, pp. 58–65, 2000.

    Google Scholar 

  12. Molinari, A., Menapace, C., Torresani, E., Cristofolini, I., and Larsson, M., “Working Hypothesis for Origin of Anisotropic Sintering Shrinkage caused by Prior Uniaxial Cold Compaction,” Powder Metallurgy, Vol. 56, No. 3, pp. 189–195, 2013.

    Article  Google Scholar 

  13. Cristofolini, I., Corsentino, N., Pilla, M., Molinari, A., and Larsson, M., “Influence of the Geometry on the Anisotropic Dimensional Change on Sintering of PM Parts,” Advances in Powder Metallurgy & Particulate Materials, Vol. 2, pp. 11–49, 2013.

    Google Scholar 

  14. ISO No. 10360-4, “Geometrical Product Specifications (GPS) — Acceptance and Reverification Tests for Coordinate Measuring Machines (CMM) — Part 4: CMMs used in Scanning Measuring Mode,” 2000.

    Google Scholar 

  15. Cristofolini, I., Rao, A., Menapace, C., and Molinari, A., “Influence of Sintering Temperature on the Shrinkage and Geometrical Characteristics of Steel Parts Produced by Powder Metallurgy,” Journal of Materials Processing Technology, Vol. 210, No. 13, pp. 1716–1725, 2010.

    Article  Google Scholar 

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Authors and Affiliations

  1. Department of Industrial Engineering, University of Trento, Via Mesiano, 77, Trento, 38123, Italy

    Ilaria Cristofolini, Nicolò Corsentino & Alberto Molinari

  2. Höganäs AB, Bruksgatan 35, Höganäs, SE-263 83, Sweden

    Mats Larsson

Authors
  1. Ilaria Cristofolini
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  2. Nicolò Corsentino
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  3. Alberto Molinari
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  4. Mats Larsson
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Correspondence to Ilaria Cristofolini.

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Cristofolini, I., Corsentino, N., Molinari, A. et al. Study of the influence of material and geometry on the anisotropy of dimensional change on sintering of Powder Metallurgy parts. Int. J. Precis. Eng. Manuf. 15, 1865–1873 (2014). https://doi.org/10.1007/s12541-014-0540-5

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  • DOI: https://doi.org/10.1007/s12541-014-0540-5

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