Rockwell vs. Vickers vs. Knoop - Does Thickness Determine the Proper Test?

[dbulak]

Is there a standard that says "at this thickness you change from rockwell to Vickers or Knoop"?

 

[Bill Ryan - 2007]

I know of no "standard". I'm not that familiar with Vickers or Knoop other than penetrator and load differences. FWIW - We use Rockwell for most of our applications (die castings and tool steel) and use the "superficial" scale for thinner materials but it's more or less guesswork as to when to switch (to the best of my knowledge).

Sorry I can't be of more help.

Bill