Thursday, January 14, 2010

[MW:4045] Magnetism in SS 304 & 321 after welding

One of my friend is facing a problem, which Im putting to the group as Im not sure about the solution..

SS joints after welding has becoming magnetic ( Ferrite number is not a criteria for these joints) and hence attracted by magnet ( including Socket Joints )- mostly pipe to fitting joints , but his Client is doubting that they are becoming magnetic because it’s root has been welded by CS filler wire- rest passes by SS filler wire.

 This , he insists is done by welder to do the job faster and save purging- as per his past experience in some Gulf project.

There are some thousand of SS joints ( 304, 321 ) in his plant, which is ready.

What can be done, apart from PMI & Ferrite ( on which he doesnt have much faith as they show the reading of the Final pass ) , to convince him about the integrity of the joint without cutting/ drilling / damaging  the joint.

Please share any literature which relates Magnetism to the Welding/ Ferrite percentage.

Welding Processes involved are GTAW (mandatory for all root welding ) and SMAW ( for above 8mm thk )

Thanks & Best Regards,
 
Rishi Raj Singh

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