Indentation testing with loads from a few grams up to 1 kgf, read optically on the Vickers (HV) or Knoop (HK) scale. On case-hardened parts, a microhardness traverse places indents at small steps inward from the surface of a polished cross section, and the curve gives effective and total case depth. Knoop's long, shallow indent suits readings very close to the edge.
Run a microhardness traverse at 0.002 steps and plot it, I want to see where it crosses 513.
Indents placed too close together or too near the edge give false readings, so keep them at least two and a half diagonals apart.
Also heard as
- microhardness traverse
- Vickers
- Knoop
- HV
- HK
Related terms
Case depth
Thickness of a hardened surface layer, measured from the surface to a specified hardness or structure.
Effective case depth
Depth below the surface where hardness falls to a set value, usually 50 HRC, on a case-hardened part.
Rockwell hardness
The standard shop hardness test that presses a diamond or ball into a part and reads depth as a number.
Cut and etch
Shop phrase for sectioning a sample part and etching it to check case depth or structure.