[MW:4129] RE: 4123] Demagnetization after completion of MPI test

Dear Mr Raghavendra,

The attached ASTM spec(Clause-12) provides brief introduction on demagnetization. From my experiences I have seen that AC magnetic coils can induce a lot less of residual magnetism thatn DC coils. PWHT effectively nullifies residual magnetism as the temperature very close to curie point.

If you have any specific recomemnedations from your client feel free to share the same.I am not posting this ASTM document in the forum due to copyright issues.

Earler I had sent you some information on Reheat cracking in Cr-Mo-V steel welds with SAW welding. Did it fit well into your information requirements. Appreeciating your response.

Thanks

Pradip Goswami, P.Eng
88,Garth Trails Crescent
Hamilton,Ontario, L9B2X1,Canada
Email-pgoswami@sympatico.ca
Email-pgoswami@quickclic.net


-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of PEMMARAJU RAGHAVENDRA
Sent: Thursday, January 21, 2010 7:24 AM
To: materials-welding@googlegroups.com
Subject: [MW:4123] Demagnetization after completion of MPI test

Dear All,

Can any one tell us the various methods / procedure  of demagnetizing the weld after completion of Magnetic particle testing on Ferritic steel welds.

Regards,

Raghavendra 

Larsen & Toubro Limited
www.larsentoubro.com

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