Branson Krautkramer MIC 10, User Manual

Page: 124 / 146

12.1 The UCI method
The following section contains some helpful informa-
tion about the hardness testing method of the MIC 10.
As opposed to conventional Vickers low load hard-
ness testers, the MIC 10 does not evaluate the
Vickers indent microscopically but electronically ac-
cording to the UCI method.
This has an advantage over the visual evaluation be-
cause high repeatability of the test results is ensured
even when small indents are measured.
The Vickers diamond is fixed to the tip of a round
metal rod. This metal rod is excited, to its resonant fre-
quency of approx. 78 kHz, into longitudinal oscillations.
When the Vickers diamond contacts the material, the
resonant frequency changes. This change happens in
relation to the size of the indent area from the Vickers
diamond. The size, in turn, is a measure for the hard-
ness of the tested material.
Resonant frequencies can be measured very accur-
ately. This is why the UCI method is suited to make
the evaluation of Vickers indents, and thus of the com-
plete test procedure, so much easier and quicker.
There are also two additional advantages:
•
The measurement is made under load.
(no impairment of the measurement due to elastic
resilience)
•
The hardness measurement is based on the area of
the indent and not on the length of the indent diago-
nals.
The measurement is thus less affected by surface
roughness; even gunmetal-finished surfaces can be
measured.
Concerning the UCI method, the measurement value
is also dependent on the Young’s modulus of the ma-
terial.
Appendix
The UCI method
12-2 Issue 08, 08/01 Krautkrämer MIC 10
12.1 The UCI method
The following section contains some helpful informa-
tion about the hardness testing method of the MIC 10.
As opposed to conventional Vickers low load hard-
ness testers, the MIC 10 does not evaluate the
Vickers indent microscopically but electronically ac-
cording to the UCI method.
This has an advantage over the visual evaluation be-
cause high repeatability of the test results is ensured
even when small indents are measured.
The Vickers diamond is fixed to the tip of a round
metal rod. This metal rod is excited, to its resonant fre-
quency of approx. 78 kHz, into longitudinal oscillations.
When the Vickers diamond contacts the material, the
resonant frequency changes. This change happens in
relation to the size of the indent area from the Vickers
diamond. The size, in turn, is a measure for the hard-
ness of the tested material.
Resonant frequencies can be measured very accur-
ately. This is why the UCI method is suited to make
the evaluation of Vickers indents, and thus of the com-
plete test procedure, so much easier and quicker.
There are also two additional advantages:
•
The measurement is made under load.
(no impairment of the measurement due to elastic
resilience)
•
The hardness measurement is based on the area of
the indent and not on the length of the indent diago-
nals.
The measurement is thus less affected by surface
roughness; even gunmetal-finished surfaces can be
measured.
Concerning the UCI method, the measurement value
is also dependent on the Young’s modulus of the ma-
terial.
Appendix
The UCI method
12-2 Issue 08, 08/01 Krautkrämer MIC 10