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 -

663 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 ?


    
 
 
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



    
 
 
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



    
 
 
S.V.Swamy
Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex , India, Joined Feb 2001, 786

S.V.Swamy

Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex ,
India,
Joined Feb 2001
786
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




    
 
 

Product Spotlight

High Resolution Industrial CT System for Small/Medium Size Parts Inspection

The YXLON FF35 CT computed tomography system is designed to achieve extremely precise inspection res
...
ults for a wide range of applications. Available in a single or dual tube configuration, it is perfect for very small to medium size parts inspection in the automotive, electronics, aviation, and material science industries.
>

Exertus Dual 120

The Exertus Dual 120 Projector has the ability to accept Iridium 192 sources or Selenium 75 source
...
s. This projector incorporates design and safety features that make it flexible, compact and lightweight. The Projector is lighter than most of its competitors. It incorporates an improved source channel, based on a new helicoidal design, which makes maintenance easier. The helicoidal design also allows smoother movement of the source assembly inside the device, making it easier for the operator and improving safety. The Projector also has a unique safety feature not found in competitive products. The source assembly locking mechanism is triggered by the source holder capsule at the front of the source assembly, thereby always assuring the operator that the source has returned to the safe position. The Exertus Dual 120 is ISO3999:2004 compliant.
>

Wireless TOFD scanner

Quick, accurate and highly reproducible welds testing. The System operates wirelessly and is compat
...
ible with any type of Windows based Laptop, Desktop or Tablet.
>

PROlineTOP Plug & Play Ultrasonic inspection device

As Plug & Play solution it units all control and operation elements in a small housing and therefo
...
re replaces the typical control cabinet...
>

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