Proceq Equotip 550 Operating Instructions Manual page 17

3.3.1.8 Testing Thin Samples
Pipes and tubes sometimes have mass distributions that can affect the
result of the Leeb hardness test due to vibration. During on-site testing
of pipelines, for example the test locations cannot be supported by solid
worktops or clamped.
To benefit from the convenience and speed of the Leeb test, the user can
make use of a custom conversion after conducting the following calibra-
tion procedure, for example:
• Data pairs are measured on reference samples. For the Leeb HLDL ref-
erence measurements, it is crucial that they are done on parts that are
installed in the same way as those to be tested on-site. For example, two
pipe samples "Pipe type 5 mm Duplex soft" (730 HLDL / 255 HB) and
"Pipe type 5 mm Duplex hard" (770 HLDL / 310 HB) are measured using
the Equotip Leeb impact device DL and a Brinell tester, respectively.
• The original HLDL-HB conversion curve for "1 Steel and cast steel"
is now adapted using the two data points. The detailed procedure on
how to create custom conversion curves in the Equotip 550 is given in
chapter "6.4 Conversion Curve Creation".
• To measure "Pipe type 5 mm Duplex" in future, it can be selected via
"Material" – "Pipe type 5 mm Duplex", using the hardness scale "HB
Brinell" also see chapter "6.4.3 Example of a Custom Conversion (Two-
Point Method)".
NOTE! The user needs to determine and qualify the adapta-
tion of conversion curves for each tube diameter and wall
thickness. Guides to the procedure are provided in Nordtest
Technical Report Series 424, Reports 99.12/13 and ASME
Final Report CRTD-91.
NOTE! It is important to include all the critical information
about the geometry of the test sample.
© 2016 Proceq SA
3.3.1.9 Material Groups
No need to select any material when measuring in the native Leeb re-
bound scale HL as no conversion is applied. In contrast, hardness scale
conversions are correct only when the appropriate material group is se-
lected. Free online material databases and the Equotip 550 on-board ref-
erence documents can be useful to assign your materials to one of the
default material groups. Suitability of conversions should be qualified on
calibrated samples before use. For further information, please consult a
Proceq representative.
NOTE! For a given test principle (native scale), the dropdown
menu only lists the material groups for which conversions
are available.
NOTE! If there is no conversion curve available, the user has
the possibility to create its their own, see chapter "6.4 Con-
version Curve Creation".
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