In this section:
The microstructure of this carburized steel was delineated using a 2% Nital etch. The depth of the carburized case (dark) was measured using 500 gram Knoop indentations.
Microhardness testing is performed to determine a material's true hardness and is conducted using a precision diamond indenter called, "Knoop or Vickers". The microhardness microscope allows accurate determination of case hardness and depth and is used to certify conformance to hardness requirements for carburizing, nitriding, plasma nitriding, induction, flame and many other surface hardening processes.
In cases where a surface hardened microstructure appears abnormal, microhardness testing can be used to identifying soft ferrite (a decarborized layer) from hard carbides.
The following terms relate to microhardness testing: