1. SANJEEV RATHORE :SSE/PWAY/USFD/DHG
STAR-CRACK
SANJEEV-KUMAR-RATHORE
S.S.E./PWAY/USFD/DHG
DIV:AHMEDABAD
WESTERN RAILWAY
11/22/2018
SANJEEV RATHORE :SSE/PWAY/USFD/DHG

2. BOLT-HOLE CRACK (STAR-CRACK)
BOLT HOLE CRACK IS DETECTABLE BY NORMAL PROBE SINCE THEY OBSTRUCT THE PATH OF SOUND WAVES AND LEAD TO DROP/LOSS OF BACK WALL ECHO.
IF THE CRACKS ARE SO LOCATED THAT THEY ARE UNABLE TO BE SCANNED BY 0°PROBES DUE TO SMALLER SIZE OR ORIENTATION,SUCH CRACKS MAY NOT BE DETECTED IN INITIAL STAGES OF THEIR DEVELOPMENT.
FOR DETECTION OF BOLT HOLE CRACKS,37°PROBE ARE IDEAL.THIS IS BECAUSE THE CRACKS DEVELOPING FROM BOLT HOLES ARE GENERALLY OBLIQUE AND PROPOGATE IN THE ZIG-ZAG MANNER
11/22/2018
SANJEEV RATHORE :SSE/PWAY/USFD/DHG

3. SANJEEV RATHORE :SSE/PWAY/USFD/DHG
FIGURE:STAR-CRACK-1
FIGURE-1
FIGURE-2
11/22/2018
SANJEEV RATHORE :SSE/PWAY/USFD/DHG

4. FIGURE-STAR-CRACK=2
SANJEEV RATHORE :SSE/PWAY/USFD/DHG
11/22/2018

5. SANJEEV RATHORE :SSE/PWAY/USFD/DHG
FIGURE-STAR-CRACK-3
11/22/2018
SANJEEV RATHORE :SSE/PWAY/USFD/DHG

6. FIGURE-STAR-CRACK-4
SANJEEV RATHORE :SSE/PWAY/USFD/DHG
11/22/2018

7. BOLT-HOLE CRACK(STAR-CRACK BY O°,4MHZ
BOLT-HOLE WITHOUT CRACK
BOLT- HOLE WITH CRACK
PRESENTED BY SANJEEV RATHORE S.S.E.(PWAY)/USFD/DHG
11/22/2018

8. STAR- CRACK NOT DETCTABLE BY 0°PR4OBE
11/22/2018
SANJEEV RATHORE :SSE/PWAY/USFD/DHG

9. BOLT HOLE CRACK BY 37°PROBE
PROBE=37°PROBE(F/B)
FREQUENCY=2MHZ
RANGE=200MM
PLACE=PROVIDED IN SINGLE RAIL TESTER IN PLACE OF NON GAUGE FACE 70°PROBE(F/B)
SENSITIVITY SETTING=THE PROBE SHOULD BE DETECT A 5MM LENGTH SAW CUT AT THE BOLT HOLE LOCATION ORIENTED AT 53°AS SHOWN IN FIGURE.BY BOTH FORWARD &BACKWARD PROBE. THE AMPLITUDE OF SIGNAL SHALL BE ADJUSTED TO 60% OF FULL SCEEEN EIGHT
PROCEDURE= THE 37°PROBE F/B SHALL BE FIXED IN RAIL TESTER IN PLACE OF NON GAUGE FACE 70° PROBE WITH SUITABLE PROBE HOLDER SO THAT THE PROBE RUNS ON CENTRAL PORTION OF THE RAIL HEAD
ROUND FREQUENCY=ONCE IN A YEAR BEFORE WINTER DURING NORMAL TESTING AS DUE
11/22/2018
SANJEEV RATHORE :SSE/PWAY/USFD/DHG

10. STAR-CRACK - BY 37°PROBE
SANJEEV RATHORE :SSE/PWAY/USFD/DHG
11/22/2018

11. FIGURE SHOWING BEAMPATH OF37°PROBE
SANJEEV RATHORE :SSE/PWAY/USFD/DHG
11/22/2018

12. DETECTION OF STAR-CRACK
SANJEEV RATHORE :SSE/PWAY/USFD/DHG
11/22/2018

13. CLASSIFICATION OF RAIL DEFECT FOR 37°PROBE
TYPE OF PROBE
TYPE OF DEFECT
OSCILLOGRAM PATTERN
CLASSIFICATION
(A) 37° PROBE SENSITIVITY SET AT 5MM SAW CUT ORIENTED AT53°
BOLT HOLE CRACK
1) IN FISH PLATE ZONE
2)IN TUNNEL&APP
3)MAJOR BRIDGE AND APPROACHES 100M EITHER SIDE
FLAW ECHO SHOWING MORE THAN 10% HORIZONTAL AND 20% VERTICAL HEIGHT
IMR
(B)
37° PROBE SENSITIVITY SET AT 5MM SAW CUT ORIENTED AT53°
BOLT HOLE CRACK OTHER THAN LOCATION (A)
1)HORIZONTAL=MORE THAN 15% &VERTICAL=MORE THAN 40%
2)HORIZONTAL=MORE THAN 10% &VERTICAL=MORE THAN 20% ……… THAN OPEN FISH PLATE AND CHECK
(P)…ANY CRACK FOUND VISUALLY ………………..=
Q)…NO VISUAL CRACK FOUND………………………-=
OBS
11/22/2018
SANJEEV RATHORE :SSE/PWAY/USFD/DHG

14. SANJEEV RATHORE :SSE/PWAY/USFD/DHG
STAR-CRACK
DETECTABLE-PROBE
1) 0°PROBE,4MHZ
2) 37°PROBE,2MHZ
11/22/2018
SANJEEV RATHORE :SSE/PWAY/USFD/DHG