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 -

Sonatest Ltd
From our three distinct business centres in the UK, USA and CANADA, Sonatest design and produce a leading range of high performance ultrasonic NDT equipment and accessories.
762 views
Technical Discussions
LANRE ALAPINI
NDT Inspector,
NDT TRAINING AND TESTING CENTRE HOUSTON TEXAS USA, Nigeria, Joined Nov 2008, 3

LANRE ALAPINI

NDT Inspector,
NDT TRAINING AND TESTING CENTRE HOUSTON TEXAS USA,
Nigeria,
Joined Nov 2008
3
06:27 Dec-09-2008
flaw checking

can any body explain the term lack of back wall reflection


 
 Reply 
 
James Boaden
Sales,
Midas NDT Systems Ltd., United Kingdom, Joined Jun 2002, 6

James Boaden

Sales,
Midas NDT Systems Ltd.,
United Kingdom,
Joined Jun 2002
6
07:00 Dec-09-2008
Re: flaw checking
----------- Start Original Message -----------
: can any body explain the term lack of back wall reflection
------------ End Original Message ------------

Using ultrasonics, a signal is generated that reflects back from the back surface of a component (when generated outside the component some sound reflects off the front surface and some penetrates, this then reflects off the back surface).

You should always get reflections from the back surface unless something stops the sound reaching it. Lack of back wall reflection dictates that a defect has stopped the sound reaching the back surface and the area of lack of back surface will be the same as the planar area of the defect.


 
 Reply 
 
S.V.Swamy
Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex , India, Joined Feb 2001, 787

S.V.Swamy

Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex ,
India,
Joined Feb 2001
787
07:36 Dec-09-2008
Re: flaw checking
----------- Start Original Message -----------
: can any body explain the term lack of back wall reflection
------------ End Original Message ------------

Lack of back wall reflection or echo means that the transducer is not receiving the ultrasound signal reflected from the back surface (opposite side of the test object). This can happen due to one or more of the following reasons:

It is assumed that the instrument and the probe are working and that the range has been calibrated properly.

Very rough surface resulting in poor coupling

Highly curved surface resulting in sound not entering the test object

Lack of parallelism between the test surface and the back surface, for example a wedge

Sintered material with lot of porosity.

We had some interesting experiences while testing hot rolled austenitic stainless steel plates and tungsten-copper blocks. If any one is interested, I will share. Or I may submit a short case study like paper.

Swamy
NDT Guru





 
 Reply 
 

Product Spotlight

High-end Ultrasonic Flaw Detector with 32:128PR PAUT and 2-ch TOFD: SyncScan 2

SIUI’s newly launched SyncScan 2, is a high-end ultrasonic flaw detector with 32:128PR PAUT and
...
2-ch TOFD, which can maximize your efficiency for PA and TOFD. ● Support PA/TOFD/UT ● 32-ch PA is more suitable for inspection on extra-thick wall and high-attenuation material. ● 32-ch PA and 2-ch TOFD work simultaneously. ● Support PR mode for corrosion inspection.
>

Immersion systems

ScanMaster ultrasonic immersion systems are designed for high throughput, multi shift operation in a
...
n industrial or lab environment. These fully integrated systems provide various scanning configurations and incorporate conventional and phased arrays technologies to support diverse applications, such as inspection of disks, bars, shafts, billets and plates. All of ScanMaster immersion systems are built from high accuracy scanning frames allowing for scanning of complex parts and include a multi-channel ultrasonic instrument with exceptional performance. The systems are approved by all major manufacturers for C-scan inspection of jet engine forged discs. Together with a comprehensive set of software modules these flexible series of systems provide the customer with the best price performance solutions.
>

Semi-Automated Phased Array Immersion System for Small Composite Parts

Turn-key semi-automated system as an improved and affordable solution for inspection of small comp
...
osite parts. Includes support table, immersion tank, scanner, PA instrument, PC, Analysis software, database, wedge management and other options.
>

Aerospace Systems - Automated Ultrasonic Inspection

USL are specialists in the design and manufacture of turnkey ultrasonic inspection systems for aer
...
ospace applications. From monolithic composites to complex honeycomb structures. This video shows just a few examples of what is possible, find out more at: www.ultrasonic-sciences.co.uk
>

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