11
Calibration Procedures
Special Code Required to Perform this Procedure!
This procedure should be performed by highly skilled personnel only! If you are experiencing erratic
results with your MET, you should contact Phase II and arrange for an inspection prior to making any
changes.
‘Calibration’ mode and all operations under this mode shall be performed separately for U1 ultrasonic
transducer and D1 dynamic transducer.
Hardness tester calibration means that that the unit in question will be adjusted to fall within NIST
tolerances on calibrated test blocks.
For hardness tester calibration by user, it is necessary to have two reference hardness blocks with
maximum and minimum values in the hardness scale.
Examples:
•
for calibration along the whole ‘C’ Rockwell scale, two reference hardness blocks are required
with the values of (25±5) HRC and (65±5) HRC.
•
If you do not use the whole range of ‘C’ Rockwell but only the range of 20÷40 HRC, perform
the calibration on reference hardness blocks with the values of (25±5) HRC and (45±5) HRC.
Reasons to perform a calibration:
•
If the hardness tester verification
on
the reference hardness blocks differ from the
nominal
value
of
the reference hardness block; example: (Block is HRC 45.5 and results are 49.3)
•
after long periods of storage (more than 3 months);
•
after intensive operation (more than 200.000 measurements for U1 ultrasonic transducer
and 50.000 for D1 dynamic transducer);
•
in case of considerable change in the conditions of operation (temperature, humidity etc.)
