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 -

Airstar Inc.
Application of the newest technologies, such as air-coupled ultrasound, digital instrumentation, signal processing, and transducer technology.
700 views
Technical Discussions
Don
Don
05:57 Jan-04-2005
Eddy current sensors for micro defects

Has anybody any experience of using eddy currents for the detection of surface-breaking micro-defects, around 0.1mm in length. I have seen several papers discussing probe designs, but has anybody actually seen or used these in real life ?


    
 
 Reply 
 
Dr.Raimond Grimberg
R & D, Professor
National Institute of R&D for Technical Physics, Romania, Joined Nov 2001, 2

Dr.Raimond Grimberg

R & D, Professor
National Institute of R&D for Technical Physics,
Romania,
Joined Nov 2001
2
02:33 Jan-05-2005
Re: Eddy current sensors for micro defects
----------- Start Original Message -----------
: Has anybody any experience of using eddy currents for the detection of surface-breaking micro-defects, around 0.1mm in length. I have seen several papers discussing probe designs, but has anybody actually seen or used these in real life ?
------------ End Original Message ------------

We have a lot of experience for detecting the microcracks. we use for this, two types of probes:
- microfocussed AC transducers with orthogonal coils
- EC microsensors array and specifically algorithms for localizing the defect.
In the case in which you need details, don't hesitate to contact us.
Best regards,
Raimond Grimberg



    
 
 Reply 
 
Steven Plummer
Steven Plummer
01:56 Jan-18-2005
Re: Eddy current sensors for micro defects
I can see you have a knowledge of non destructive testing could you help me out with a problem. I have a 600mm diameter pressure vessel with a 8mm wall thickness. it is made from large preformed sheets which are welded together. Could anyone tell me the likely modes of failure and the ndt method which should be used? will there be any particular problems that will be encountered.

I would be grateful for your response



    
 
 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
07:23 Jan-22-2005
Re: Eddy current sensors for micro defects
----------- Start Original Message -----------
: I can see you have a knowledge of non destructive testing could you help me out with a problem. I have a 600mm diameter pressure vessel with a 8mm wall thickness. it is made from large preformed sheets which are welded together. Could anyone tell me the likely modes of failure and the ndt method which should be used? will there be any particular problems that will be encountered.
: I would be grateful for your response
------------ End Original Message ------------
Dear Steven,

Greetings. The welds are the weakest area, assuming that the plates were ultrasonically tested for laminations before being pressed and that the pressing did not introduce deep surface cracks on the convex side (which can be checked out by dye penetrant testing and or magnetic particle testing). The welds (I am assuming they are butt welds) should have been tested using liquid penetrant test during the welding and by x-ray radiography finally.

If you are able to, you can rig up an Acoustic Emission Test with a few channels so that during pressurisation, any growing crack will set off AE alarm, so that the pressurisation can be stopped without the welds actually failing.

Best wishes.

Swamy




    
 
 Reply 
 

Product Spotlight

EKOSCAN Phased Array

In order to always fit your needs, EKOSCAN can manufacture any type of UT transducer, either convent
...
ional or Phased Array. As an ISO 9001: 2015 certified company, EKOSCAN is extremely careful as far a material selection and manufacturing processes are concerned. Our probes guarantee our customers the benefits of latest innovations regarding piezo-composite, backing, impedance adaptation layer, etc. Specific probes for hostile environment: high temperature, high pressure, corrosive environment,etc. Specific probes designed to fit your specific application: optimization of every parameter to guarantee you the best detection.
>

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
>

FD800 Bench Top Flaw Detectors

The bench-top FD800 flaw detector range combines state-of-the-art flaw detection with advanced mater
...
ial thickness capabilities. Designed for use in the laboratory these gauges are the tool you need for all your flaw detecting needs.
>

Teletest Focus+

Teletest Focus+ electronics have superior capabilities than rivals on the market. Beyond the usual
...
test features, Focus+ has 24 transmit channels and 24 receive channels, with an additional on-board switching capabilities. The instrument's frequency range is 10–300 kHz.
>

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