where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -
637 views
Technical Discussions
IceClampers
IceClampers
08:30 Mar-02-2001
UT Thickness Testing

When taking UT readings on pipe using a dual probe, why is it prefered to keep the axis of the probe perpindicular to the axis of the pipe being tested.


 
 Reply 
 
Tom Nelligan
Engineering,
retired, USA, Joined Nov 1998, 390

Tom Nelligan

Engineering,
retired,
USA,
Joined Nov 1998
390
09:45 Mar-02-2001
Re: UT Thickness Testing
: When taking UT readings on pipe using a dual probe, why is it prefered to keep the axis of the probe perpindicular to the axis of the pipe being tested.
.

Because that orientation optimizes sound coupling. The barrier that separates the transmitter and receiver sides of dual probes is a dead zone. When you couple any flat probe onto a small-radius cylinder, the actual area of contact is only a thin line. If you hold the dual so that the barrier is parallel to the axis of the pipe, much of that narrow contact area is occupied by the barrier, and only a small amount of energy transfers into the pipe. But if you hold the dual so that the barrier is perpendicular to the center axis, then you have an area of contact that spans the full active width of the probe and maximizes sound transmission in and out.

It's a good idea to get into the habit of holding the dual perpendicular to the axis in all cases, but it becomes most important as the pipe diameter gets smaller (especially on diameters under 25 mm or 1 inch).

--Tom Nelligan




 
 Reply 
 
Raúl Navarrete
Consultant, teacher ndt inspector
METAL-MET, C.A., Venezuela, Joined Jul 2000, 8

Raúl Navarrete

Consultant, teacher ndt inspector
METAL-MET, C.A.,
Venezuela,
Joined Jul 2000
8
02:00 Mar-02-2001
Re: UT Thickness Testing
: When taking UT readings on pipe using a dual probe, why is it prefered to keep the axis of the probe perpindicular to the axis of the pipe being tested.
.

This is also due the correction pattern. When you hold the probe parallel to the pipe axis, the way of the sound will follow the curve of the pipe diameter. If you hold it perpendicular to the axis, the path way will be on a straight pattern, not folloing any curve. So the correction to be made (because is a dual transducer) is easier and accurate than the another one. So that is why you MUST use the probe with its axis perpendicular to the pipe axis.



 
 Reply 
 

Product Spotlight

Robotic laser shearography enables 100% inspection of complex, flight-critical composite structures

An article in “Composites World Magazine” showcases Non Destructive Testing of aero-structures
...
with Laser Shearography. Over the years Dantec Dynamics has supplied many solutions for the aerospace industry. Referring to specific customer projects several of these cases are examined to outline the advantages of using Laser Shearography for automated defect detection.
>

MUSE Mobile Ultrasonic Equipment

The MUSE, a portable ultrasonic imaging system, was developed for in-field inspections of light-weig
...
ht structures. The MUSE consists of a motor-driven manipulator, a water circulation system for the acoustic coupling and a portable ultrasonic flaw detector (USPC 3010). The MUSE provides images of internal defects (A-, B-,C- and D-scan).
>

FMC/TFM

Next generation for Phased Array UT is here now with FMC/TFM! Have higher resolution imaging, impr
...
oved signal to noise ratio, characterize, size and analyze defects better with access to several wave mode views and save raw FMC data for higher quality analysis.  Some of the benefits are:
  • Beautiful Image! Easier to understand what you're looking at
  • Completely focused in entire image or volume
  • Much easier to define setups before inspection
  • Easier to decipher geometry echoes from real defects
  • Oriented defects (e.g. cracks) are imaged better
  • See image from different wave modes from one FMC inspection
  • FMC data can be reprocessed/analyzed without going back to the field
>

NOVO Armor 15 & NOVO Armor 22

The Armor Kit Contains the NOVO Armor, which provides additional mechanical protection to the NOVO 1
...
5WN & NOVO 22WN Detectors, the Armor Stand and a traveling soft cover. - Newest shock absorbent technology case - Water resistant design - Supports wired & wireless communication - Multiple positioning options - Tripod connection using the Built-in 1/4” threads - Simple Detector battery replacement
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window