Ultrasonic Testing procedure by Trinity NDT, Bangalore, India-Twin Crystal calibration
Ultrasonic Testing procedure by
Trinity NDT, Bangalore, India-Twin Crystal calibration
Calibration procedure for 25mm
steel Using Dual Crystal Transducer
1. Connect probe leads to Ultrasonictesting equipment using two cables, select twin crystal Mode.
2. On the Ultrasonic testing
equipment, select the test range to 10mm position and Ultrasonic test velocity
inside the steel is 5920m/s to be adjusted on the equipment
3. Using Gain Control select the
gain at approximately 40 dB
4. Switch Suppression (Reject)
Control to off.
5. Position leading edge of Initial
pulse at ‘0’ on the Ultrasonic testing machine screen grid line.
6. Apply couplant to the 'V1'
block and place probe on the block. There should be no change in display since
25mm thickness of block will be outside range of the base at present.
7. Adjust the echoes such that a
2nd signal should appear to the right side of the ultrasonic equipment screen.
This is 1st Back wall echo from IIW V1 block 25mm thickness
8. Using delay control adjust the
initial pulse to ‘0’ on the Ultrasonic equipment screen
9. Adjust the Range and Delay
controls to get the Initial pulse and BWE from 25mm thickness of the block on
screen
10. Adjust delay control to move
the 1st BWE to center of the screen. Second Back wall echo now will
be appearing towards the right side of the Ultrasonic test equipment display.
11. Using delay control adjusts
the 1st BWE to ‘0’ and using range control adjusts the 2nd
BWE to the extreme right side of the screen (end of the screen). Repeat the
adjustments if needed to adjust the 1st BWE to ‘0’ and 2nd
BWE to the extreme right side of the screen.
12. Now using delay control bring
the 1st BWE to the extreme right side of the screen. Now the
distance between Initial Pulse and 1st BWE is 25mm and the total
range calibrated using twin crystal is 0-25mm of steel. (Note: There may not be
an Initial pulse after this calibration on the Ultrasonic equipment screen)
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