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mvip@mitech-ndt.com
Material Selection
Hardness/Strength
switch
Plus or Up
Hardness
Scale
Selection
Direction change
Minus or Down
Print data
Impact Times set
Data logging or Enter
Press
key to store present group of measured value into memory. This operation is only valid
after displaying the mean value.
Press key
and
could display single measured value.
Press
key could switch on of off the background light of LCD.
Press
key to set the impact direction.
Press
key to change the impact times in one group. The impact times item will flash when first
pressing the
key, and then the impact times value will plus or minus when pressing the
or
key. Press
key finally to exit from changing the impact times process.
Press
key to change the hardness scale.
Press
key to change the material. Presetting hardness scale recovers to HL automatically after
material presetting changed.
Press
key to switch between hardness test and strength test. Only D and DC type of impact
device has the function of strength testing. So hardness testing is the only selection if the impact
device is not D or DC type.
Press
key to print out the measured values after measurement.
2.4 Leeb Hardness Testing Principle
The basic principle is to use an impact body of certain weight impacts against the testing surface under
certain test force, then measure the impacting velocity and the rebounding velocity of the impact body
respectively when the spherically test tip is located 1mm above the testing surface.
The calculation formula is as follows:
HL=1000×VB/ VA
Where, HL—— Leeb hardness value
VB—— Rebounding velocity of the impact body
VA—— Impacting velocity of the impact body
3 Preparation
3.1 Instrument Preparation and Inspection
Verification of the instrument is by using standard test block. The error and repeatability of displayed
value should be within the regulation of Appendix table 2. The instrument and impact device must be
calibrated using a standard hardness block before use as the first time, or having not been used for a
long time, or having reset the instrument system.
Press
key, meanwhile pressing down the
key to power on the system. Then the user calibration
screen shows as left below.
Test for 5 points on the standard hardness block.
It would display the average measured value
after measuring 5 times. Press
key to
change to its nominal value.
Press key to confirm the calibration finally. Or
press the
key to cancel the calibration.
Range of adjustment: ±30HL.
