|Mario Belo |
Trenes Buenos Aires, Argentina, Joined Jan 2000, 7
Is it possible, to determine the transference corrections (surface and attenuation) from a reference block with endless wall (V1/5) to an unknown flaw (smaller than the beam) in a certain piece with different acoustic characteristics and a different surface, which does not present backwall, through the correspondent AVG (DGS) diagram?
An example would be welcome.
|Udo Schlengermann |
Standards Consulting, Germany, Joined Nov 1998, 176
Re: Corrections calculation reply by Udo Schlengermann
If you calibrate on a block which has different material and surface than the test object, this is not possible, for the following reasons:
Four different losses determine the signal amplitude:
1. divergence - depending on the frequency, the roughness and the size of the contact area.
2. attenuation - in reference block and test object.
3. transmission losses - if the materials are different for both objects (acoustical impedances).
4. reflectivity of reflectors - calibration reflector and detected discontinuity.
The DGS diagram is designed for a full size contact (effective transducer diameter) and a material without attenuation.
Most standards therefore allow DGS method only if the curvature compared to transducer size is below a limit.
Transfer losses on curved, rough objects therefore are only valid for a given contour and roughness, and a defined distance of reflectors, i.e. they change with distance, if attenuation is not comparably equal on both objects.
Before using transfer losses, they have to be determined on a test block having the same curvature and the same roughness as the test object, containing the same reflector (e.g. backwall) at the same distance than your calibration block. Then losses no 4. and 3. are constant in both cases and the remaining difference to the DGS-curve is the transfer loss (attenutation and transmission losses).
It is therefore necessary to have at least one reflector of known size and distance in the test object. You cannot determine transfer losses using an unknown reflector.
: Dear experts:
: Is it possible, to determine the transference corrections (surface and attenuation) from a reference block with endless wall (V1/5) to an unknown flaw (smaller than the beam) in a certain piece with different acoustic characteristics and a different surface, which does not present backwall, through the correspondent AVG (DGS) diagram?
: An example would be welcome.
: Best regards,
: Mario Belo
Varex Imaging Large Field of View (FOV) Digital Detector Arrays (DDAs)
A larger FOV DDA can reduce the space and volume of the X-ray inspection system on the factory floor
, enable faster scanning times, better throughput and better resolution images at a lower dose. Customers can also save time and money. With these benefits in mind, Varex Imaging has designed a family of large FOV detectors (4343HE, XRD 1611, 4343DX-I, 4343CT) for our industrial imaging customers.
NEW - TD Focus-ScanRX
The NEW Next Generation Advanced UT platform, TD Focus ScanRX - Also available as a card stack solut
1. Data acquisition is significantly faster than current design
2. Better aesthetic – closely aligns with HandyScan RX
3. Improved IP rating (Target IP66)
4. Ruggedized housing
5. Connectors are protected from impact and ingress
6. Integrated stand and separate retractable handle
easy to keep clean)
7. Touchscreen with ruggedized display glass
8. 3-Axis encoder input
Navic - Steerable Modular Automated Scanner
The Navic is a modular, motorized, steerable scanner designed to
carry multiple attachments
in various scanning and inspection applications. The Navic is
capable of weld scanning
(girth welds and long seam welds), automated corrosion mapping,
and tank scanning.