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 -

897 views
Technical Discussions
Ehsan
Ehsan
06:11 Mar-09-2009
Circular shot current calculation

Dear All,
as per ASTM for circular shot NI=K/(L/D).
but i am not very clear at the time of calculating L/D for many parts Viz Crankshaft/Camshafts/spindles and other difficult geometry components.
your valuable responce are awaited.

Thanks

Ehsan

 
 Reply 
 
Michel Couture
NDT Inspector,
consultant, Canada, Joined Sep 2006, 891

Michel Couture

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
891
15:49 Mar-09-2009
Re: Circular shot current calculation
In Reply to Ehsan at 06:11 Mar-09-2009 (Opening).

Ehsan,

Andreas brought a valid point. But one thing I would like to mention to all who do MT is the formulas given in ASTM E709 and E1444 are in my opinion only guidleine or starting point if you will. On factor we never really consider in our calculation is: "permeability".

For this reason, when I taught MT, I used to tell my students the calculations are only a starting point. I would always magnetised my parts using a lower amperage than what my calculation showed me. Always, verify with my pie gauge or QQI to ensure you are getting the proper magnetisation. You will be surprise at how low the amperage is compare to calculations. Other things to consider when doing MT is particle mobility and background.

One other thing, whenever you do MT, try to picture the part as being a straight piece of round stock. You were talking about a crackshaft, well how long would it be if it was straight?

Remember, always verify your magntisation with a QQI or pie gauge.

Cheerio's

I hope this will be of help.

 
 Reply 
 
Andreas
NDT Inspector, Specially in the oilfield
Tuboscope Vetco(Deutschland)Gmbh, Germany, Joined Oct 1999, 131

Andreas

NDT Inspector, Specially in the oilfield
Tuboscope Vetco(Deutschland)Gmbh,
Germany,
Joined Oct 1999
131
19:17 Mar-09-2009
Re: Circular shot current calculation
In Reply to Michel Couture at 15:49 Mar-09-2009 .

The E 709 eveen state that is only a guideline and you should verify the field by a "gausmeter" , correct would be a Tesla meter to use correct SI units.
I like the so called "Burmah-Castrol strip" , it shows you the magnitude and direction of the field.
If you see the three indication on the strip ,the field is 2.4 kA/m or greater (2 - 6 kA/m is required by EN specs).If not placed perpendicular (90° ) to the applied magnetic ,then no indication will be shown.

 
 Reply 
 

Product Spotlight

Conformable wedge transducer

The conformability is obtained with a flexible membrane filled with water between the transducer and
...
the inspected component. The coupling between the membrane and the component requires a small quantity of water or couplant. The conformable wedge combines the acoustic performance of immersion technique with good coupling and low attenuation.
>

IntraPhase Athena Phased Array System

The Athena Phased Array system, manufactured by WesDyne NDE Products & Technology, consists of a pha
...
sed array acquisition system and PC running IntraSpect software. A PC is used to perform acquisition, analysis and storage of the data. System hardware is capable of operating up to four data sets with any combination of phased array or conventional UT probes. NOW AVAILABLE IN 64-64 CONFIGURATION.
>

PAUT Probes

Typical Phased Array probes have frequencies between 1MHz and 20MHz and the number of wafers is 10
...
to 128. M2 Electronics offers customers conventionally ultrasound probes and the ability to provide high-precision Phased Array Ultrasound Probes of up to 256 wafers. We can also customize the probe for our customers to meet the specific application requirements of the user.
>

Ultrasonic Probe Recharacterization Service

NDT Systems offers a comprehensive Aftercare and Recharacterization Service for all our ultrasonic
...
probes. The Recharacterization Service is fully compliant with International ASTM E1065 Standard Guide (and other applicable standards) and offers complete documentation, traceable to the ASTM E1065 Standard. For more details or to schedule Recharacterization Services contact ndtsales@ndtsystems.com
>

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