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Units of vickers,brinell and rockwell . . .

  1. Nov 4, 2009 #1
    hello everyone.

    a little question...(or mybe two...)...

    why does vickers and brinell hardness test have the units of stress ?

    and why does rockwell test has no units at all ?

    thanks to all !
  2. jcsd
  3. Nov 4, 2009 #2


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    Hi kafri09, welcome to PF. Hardness is a measure of resistance to yield (plastic deformation), and the yield strength [itex]\sigma_y[/itex] has units of stress. Thus, the Vickers and Brinell hardness measurements, which are related to [itex]\sigma_y[/itex], do too. The Rockwell hardness is measured on a calibrated scale, where the calibration points correspond to well-defined tests on well-defined materials (similar to the temperature scale, which is calibrated by certain equilibrium phase change reactions). Does this answer your question?
  4. Nov 4, 2009 #3
    yes it does.

    thank u Mapes!
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