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Re: [MW:9539] Duplex stain less steel certificates misses nitrogen content

By Materials & Welding
Replied below to yor queries.
Regards,
Ajay
From: murugesan jeyaraman <jmurugesan@gmail.com>
To: materials-welding@googlegroups.com
Sent: Fri, January 28, 2011 5:17:07 AM
Subject: [MW:9532] Duplex stain less steel certificates misses nitrogen content

Dear all
 
I reviewed a Material certificate for Duplex SS, Plate A240 UNS S31803 and found Nitrogen content .08 – 0.2% as required by ASME sec II part A is not at all mentioned in the certificate. As vessels are fabricated and welded I issued a NCR to manufacturer.

 

Vessel manufacturer are going to ask Mill about this.

 

1) My question is how come a Mill certificate misses an essential element of composition required by the code?  If the Mill comes with a reply that it is a clerical error to miss the Nitrogen content, and re-issue a certificate, can we accept it as genuine?

It may happen, sometimes the Mill misses to include such information. I believe, if the Mill re-issues the certificate afte correction, then you can accept it.

 

2) Is nitrogen content can be analysed by PMI or any other analyzing method in a lab test. Because the vessel fabricator say they are going to do lab test, for this.

The vessel manufacturer may have left over materials of same heat, which can be chemically tested at lab's for more perfect analysis or even by PMI as suggested by Mr. Karthik.

 

Please share your experiences and opinion about this.

 

Thanks

 

Murugesan

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