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 -
3688 views
Technical Discussions
Mulianto Sinaga
NDT Inspector, -
-, Indonesia, Joined Sep 2009, 4

Mulianto Sinaga

NDT Inspector, -
-,
Indonesia,
Joined Sep 2009
4
14:38 Feb-06-2010
yoke pole spacing

Dear all,

I want to know what's the affect of pole spacing of yoke if I open the pole too close?

 
 Reply 
 
Godfrey Hands
Consultant,
PRI Nadcap, United Kingdom, Joined Nov 1998, 305

Godfrey Hands

Consultant,
PRI Nadcap,
United Kingdom,
Joined Nov 1998
305
14:55 Feb-06-2010
Re: yoke pole spacing
In Reply to Mulianto Sinaga at 14:38 Feb-06-2010 (Opening).

Hi Mulianto,
If you open the poles up too far, then the magnetic field between the poles may not be enough to detect the cracks you need to find.
If you keep them too close together, there are two risks
1. You will get a smaller coverage, so need to test next test much closer
2. You may saturate with magnetism and cause too big a background to see cracks.

That's a very simple explanation. Hope it helps.

Godfrey

 
 Reply 
 
Jim Draper
Consultant, ASNT Level III MT PT RT VT
Draper NDT, USA, Joined Jul 2009, 99

Jim Draper

Consultant, ASNT Level III MT PT RT VT
Draper NDT,
USA,
Joined Jul 2009
99
17:23 Feb-06-2010
Re: yoke pole spacing
In Reply to Godfrey Hands at 14:55 Feb-06-2010 .

Mulianto,

I use a Parker DA 200 probe. My manual recomends 5 to 6 inches between the legs. Here is a link to a PDF of the manual. I hope this helps.

http://www.parkreshcorp.com/pdfopinstr/DA200.pdf

 
 Reply 
 
ezio
Other, Retired ex Laboratory Technical Manager
OMECO Research Centre, Italy, Joined Sep 2008, 275

ezio

Other, Retired ex Laboratory Technical Manager
OMECO Research Centre,
Italy,
Joined Sep 2008
275
20:28 Feb-06-2010
Re: yoke pole spacing
In Reply to Mulianto Sinaga at 14:38 Feb-06-2010 (Opening).

You can see the effect with a simple specimen: a plate 50x250x20 mm with a subsurface 1-1,5 mm hole on the side. Good look, ciao, ezio

 
 Reply 
 
rama
NDT Inspector, -
Kuwait, Joined Jan 2010, 13

rama

NDT Inspector, -
Kuwait,
Joined Jan 2010
13
08:59 Feb-07-2010
Re: yoke pole spacing
In Reply to Mulianto Sinaga at 14:38 Feb-06-2010 (Opening).

Pole spacing too close means the magnetic field between the the poles will be greater and it leads to non relevant indications named as banding.

 
 Reply 
 
RENATO BANAGA
Engineering,
Philippine Nuclear Research Institute (PNRI), Philippines, Joined Jul 2005, 8

RENATO BANAGA

Engineering,
Philippine Nuclear Research Institute (PNRI),
Philippines,
Joined Jul 2005
8
11:24 Feb-08-2010
Re: yoke pole spacing
In Reply to rama at 08:59 Feb-07-2010 .

Hi, Mulianto,

Making your Yoke pole spacing too close will create too much sensitivity due to the increase in the magnetic field strenght and that creates unnecessary indications. On the otherhand, making your pole spacing too far would provide lesser magnetic field strenght (lesser sensitivity).
So it is better for you to established your own correct pole spacing by doing some experimentation using same material of the same thickness with a known artificial defect and with that you can make your own appropriate MT procedure.

Renato Banaga

 
 Reply 
 

Product Spotlight

SITEX CPSERIES

Teledyne ICM’s CPSERIES has been designed with a view to revolutionizing the handling and perfor
...
mances of portable X-Ray sets. Despite having managed to halve the weight of similar portable X-Ray generators available on the market (while continuing to provide the same power output), the SITEX CPSERIES generators feature a shutter, a laser pointer, a beryllium window, an aluminum filter and two integrated diaphragms (customized sizes are available upon request). Without compromising the robustness and reliability for which ICM products are renowned, the small size and light weight of the SITEX CPSERIES will radically change the way that you perform your RT inspections. And you will see a positive impact in terms of both quality and return on investment (ROI).
>

HARDNESS TESTER TKM-459CE combi

TKM-459CE combi applies 2 methods of hardness control: UCI and Leeb. It provides high-accuracy tes
...
ting of metals and alloys as well as items of different sizes and configurations, their hardened layers and galvanic coatings. Device represents results in HB, HRC, HV and others. Shock-, dust- and water-proof housing with intuitive software make this gauge easy to use in all working conditions.
>

Ultrasonic Squirter/Gantry System

TecScan’s NDT Ultrasonic Gantry Systems are industrial Squirter scanners designed for non-destru
...
ctive quality testing and raster scanning of large structures and parts. The Gantry Systems are usually composed of an Industrial Mechanical Scanner and a Control Room with System Workstation.
>

NEW! The PragmaPro Instrument Platform

The PragmaPro is based on a modular cartridge technology and supports various NDT instrument modal
...
ities such as UT, PAUT, ECT and many more. This new platform is based on a machined, powder-coated aluminum frame for shock-proofness, best sealing qualities and maximum heat dissipation. This is practical to extend the outdoor temperature range and/or to extend the power injected in the transducers. The PragmaPro is aiming at a very wide range of applications, such as weld scanning, corrosion mapping and composite testing.
>

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