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Effects of re-pressing under high hydrostatic pressure upon the shrinkage and density of sintered VK6 hard alloy blanks

  • V. P. Bondarenko
  • A. P. Khalepa
  • A. A. Baidenko
  • S. S. Dzhamarov
  • Yu. I. Chernyi
  • G. P. Mikhailenko
Theory and Technology of the Component Formation Process
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Conclusions

  1. 1.

    Hydrostatic re-pressing of preformed blanks can be employed as a means of producing parts of the required shape and size only in those cases where the density of the blanks is evenly distributed through-out their volume. When the distribution of density in the starting blanks is uneven, re-pressing will alter their relative dimensions and change their shape. To obtain parts of the required shape and size from blanks with an uneven distribution of starting porosity, recourse must be had after re-pressing, as in the case of parts produced by ordinary hydrostatic pressing, to machining.

     
  2. 2.

    The chief advantages of re-pressing under high hydrostatic pressure are a low value of coefficient of shrinkage after final sintering and reduced distortion of parts.

     
  3. 3.

    The density of alloy specimens, as determined by hydrostatic weighing, is virtually unaffected by re-pressing.

     
  4. 4.

    The number of large pores substantially decreases as a result of repressing only in specimens presintered at 650°C; with other types of pretreatment, the effect of pre-pressing on the number of large pores is less marked. The least number of pores is found in specimens produced by hydrostatic pressing without a plasticizer.

     

Keywords

Porosity Shrinkage Hydrostatic Pressure Relative Dimension Uneven Distribution 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Literature cited

  1. 1.
    P. W. Bridgman, Studies in Large Plastic Flow and Fracture, Harvard Univ. (1952).Google Scholar
  2. 2.
    M. Yu. Bal'shin and A. P. Dubrovskii, Dokl, Akad. Nauk SSSR,136, No. 2, 332 (1960).Google Scholar
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    G. A. Meerson, G. A. Borok, and B. P. Lobashev, Transactions of an All-Union Scientific-Technical Conference on Powder Metallurgy [in Russian], Erevan (1964).Google Scholar
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    V. I. Tret'yakov, Sintered Hard Alloys [in Russian], Metallurgizdat, Moscow (1962).Google Scholar
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    F. Clark, Advanced Techniques in Powder Metallurgy, Rowman.Google Scholar
  6. 6.
    A. G. Samoilov, Tsvetn. Metal.,4, 49 (1946).Google Scholar

Copyright information

© Plenum Publishing Corporation 1975

Authors and Affiliations

  • V. P. Bondarenko
    • 1
  • A. P. Khalepa
    • 1
  • A. A. Baidenko
    • 1
  • S. S. Dzhamarov
    • 1
  • Yu. I. Chernyi
    • 1
  • G. P. Mikhailenko
    • 1
  1. 1.Institute of Superhard MaterialsDonetsk Physicotechnical InstituteUSSR

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