Re: Pitch and catch, Tip diffraction

[ NDT-net Forum ]
[ Follow Ups ] [ Post Followup ] [ Help ]

Re: Pitch and catch, Tip diffraction
Posted by: J. Mark Davis (PID_553), E-mail: mkdavis@mindspring.com, on March 16, 2000 at 16:59 :
In Reply to: Re: Pitch and catch, Tip diffraction posted by : Jacques Parent on March 16, 2000 at 14:20:
: Thank you for the suggestion
: What would you expect the minimum detectable crack size (length and depth) to be?
This is really dictated by the Critical Flaw Size. What does the FM people say. 10% of t and 1/2 inch long???
: What would you use for calibration block design?
This should be a mock up of the actual design or a close design to incorporate the geometric limitations.
: Saw cuts OK or should we go EDM notches?
Saw cuts or notches are ok. You just need a calibration reflector to calibrate the time of flight of the UT system. With of the notch reflector is a consideration; too wide a notch and you could get tip diffracted energies from both notch edges. I suggest not widths to be between 1 to 3 mm. Small as practical.
: 10%, 20%, 40%, 60%, 80% of wall thickness OK?
Yes, but the rememebr the critical flaw size. If it is 5% then add a 5%.
: How long would you make the calibration "cracks"?

Again, what is the critical flaw size. Is length the concern or depth?
: Regards
: jp

Follow Ups:

Post a Followup:

Name:

E-Mail:

Subject:

Comments:
: : Thank you for the suggestion : : What would you expect the minimum detectable crack size (length and depth) to be? : This is really dictated by the Critical Flaw Size. What does the FM people say. 10% of t and 1/2 inch long??? : : What would you use for calibration block design? : This should be a mock up of the actual design or a close design to incorporate the geometric limitations. : : Saw cuts OK or should we go EDM notches? : Saw cuts or notches are ok. You just need a calibration reflector to calibrate the time of flight of the UT system. With of the notch reflector is a consideration; too wide a notch and you could get tip diffracted energies from both notch edges. I suggest not widths to be between 1 to 3 mm. Small as practical. : : 10%, 20%, 40%, 60%, 80% of wall thickness OK? : Yes, but the rememebr the critical flaw size. If it is 5% then add a 5%. : : How long would you make the calibration "cracks"? : : Again, what is the critical flaw size. Is length the concern or depth? : : Regards : : jp

Optional Link URL: Example: "http://www....html". Alternative write "http://www.ndt.net/wshop/attach/filename.htm" if you transfered a filename.htm via FTP

Link Title: is important! Information on my Home Page

Optional Image URL: http://www....gif

Attention! Please click the button only once. This may take a moment to process
[ NDT-net Forum ] [ Help ]

Optional Link URL:	Example: "http://www....html". Alternative write "http://www.ndt.net/wshop/attach/filename.htm" if you transfered a filename.htm via FTP
Link Title: is important!	Information on my Home Page
Optional Image URL:	http://www....gif