Re: Small Void/Inclusion detection

[ Ultrasonic Application Workshop ]
[ Follow Ups ] [ Post Followup ] [ Help ]

Re: Small Void/Inclusion detection
Posted by: Tom Nelligan , E-mail: nelligant@panametrics.com, on May 23, 1997 at 21:25:38:
In Reply to: Small Void/Inclusion detection posted by : Gerald Feldewerth on May 23, 1997 at 20:21:21:

: Are standards and techniques available to detect very small voids or inclusions in pure metals using standard C-scan equipment?? The size I am trying to detect is 0.05 to 0.1mm. If this can be accomplished can anyone tell me where I can get flat bottom holes made to use for calibration standards.
: Thanks
: Gerald
It is certainly possible, in many metals, to find voids and inclusions in the 50-100 micron range using high frequency, high resolution pulse/echo C-scan systems working in the 50 to 100 MHz range. The optimum transducer frequency should be selected based on the specific material and detection requirements at hand. This sort of equipment is commercially available from many sources. You do need high frequency capability, so check bandwidth specifications. You should also be aware that in many cases penetration at these frequencies will be effectively limited to a few millimeters due to a combination of attenuation, scattering, and the very short focal zones of typical commercial high frequency transducers.
My own laboratory has a set of very-small-hole steel reference standards that were made for us a number of years ago by a machine shop that uses EDM techniques. A number of our customers have done the same thing when evaluating our equipment. You may want to find a local vendor who can do EDM machining and design your own set of standards.
--Tom Nelligan

Follow Ups:

Post a Followup:

Name:

E-Mail:

Subject:

Comments:
: : : Are standards and techniques available to detect very small voids or inclusions in pure metals using standard C-scan equipment?? The size I am trying to detect is 0.05 to 0.1mm. If this can be accomplished can anyone tell me where I can get flat bottom holes made to use for calibration standards. : : Thanks : : Gerald : It is certainly possible, in many metals, to find voids and inclusions in the 50-100 micron range using high frequency, high resolution pulse/echo C-scan systems working in the 50 to 100 MHz range. The optimum transducer frequency should be selected based on the specific material and detection requirements at hand. This sort of equipment is commercially available from many sources. You do need high frequency capability, so check bandwidth specifications. You should also be aware that in many cases penetration at these frequencies will be effectively limited to a few millimeters due to a combination of attenuation, scattering, and the very short focal zones of typical commercial high frequency transducers. : My own laboratory has a set of very-small-hole steel reference standards that were made for us a number of years ago by a machine shop that uses EDM techniques. A number of our customers have done the same thing when evaluating our equipment. You may want to find a local vendor who can do EDM machining and design your own set of standards. : --Tom Nelligan

Optional Link URL: Example: "http://www....html". Alternative write "http://www.ultrasonic.de/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

[ Ultrasonic Application Workshop ] [ Help ]

Optional Link URL:	Example: "http://www....html". Alternative write "http://www.ultrasonic.de/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