Proceq Equotip 550 Operating Instructions Manual page 19

3.3.2 Equotip Portable Rockwell
3.3.2.1 Test Principle
During measurement with Equotip 550 Portable Rockwell probe, a diamond
indenter is forced into the test piece, and then released back out of the ma-
terial. The indentation depth is measured continuously during this process.
Indentation depth is calculated after decreasing the total load to preload.
10N
Figure 15: Portable Rockwell Test Principle
3.3.2.2 Sample Preparations
Ensure that the surface of the work piece is clean, smooth and dry. If
required, use appropriate cleaning agents for cleaning, such as acetone
or isopropanol. Do not use water or any other detergent fluids.
3.3.2.3 Measurement on Basis of DIN 50157
Both depth measurements d and d
1
application (d ) then after release of the total load (d
1
tween d and d originates from the deformation response of the material
1 2
to penetration.
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10N
50N
are taken at preload, first during
2
). The difference be-
2
NOTE! By calculating the penetration depth between the
preload and total load, surface roughness discrepancies are
significantly disregarded.
NOTE! The hardness testing principle in Portable Rockwell
follows the Rockwell stationary test. As for the Rockwell
test, no adjustment for the test direction is required. How-
ever, there are three main differences to traditional stationary
Rockwell tests:
• The test loads are lower.
• The Portable Rockwell indenter is sharper.
• The dwell times during the test are shorter.
NOTE! "MM" stands for "mobile mechanical" measurement,
an ancillary that is required by the German standard DIN
50157 to explicitly denote the lower applied loads, sharper
indenter shape and shorter loading times during a measure-
ment. The different denomination is formal, i.e. the HMMRC
results should be very close if not equal to stationary HRC
readings.
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