[MW:5842] FW: 5836] PMI using Spectroscope JR on SDSS(F53) flanges

Dear Satyaprakash,

As per API-578 , a variety of PMI test methods are available to determine the identity of alloy materials.The primary methods accepted by API are  portable X-ray fluorescence (XRF), portable optical emission spectroscopy and laboratory chemical analysis.As you must be aware  XRF can not detect all elements.Elements lighter than sulfur (S) can not be detected using portable XRF.Therefore, this technique can not be used to detect carbon (C). An optical emission spectrograph is useful to check for all the required elements, including carbon. Any burn damage resulting from the usage of the emission spectrograph shall be removed by grinding prior to inspection acceptance.

Looking at the attached picture, the spots where PMI was done looks intensely dark.However sometimes pictures could be overblown. I would think the following may be of help:-

1. Grind off all the spots.
2. If possible perform  hardness check on all the PMI spots and adjacent base metal. If the reading are close then there is not issue.
3. As an additional requirement, take  acetate replica on one sample spot per flange.The replica should cover the PMI spot and adjacent base metal.If there is no discrepancy of microstructure then there is no metallurgical damage.

 

If the above tests are a success, then pickle and passivate the ground areas as per the applicable specification.

 

If there  are any concerns i.e for deeper marks, a skin cut for machining may be recommended.However as stated below if pencil grinding is able to remove all then, machining would be not be required.

 

Hope this would help you.

 

Thanks.

 

Pradip Goswami,P.Eng.

Welding & Metallurgical Engineer/Specialist

Ontario Power Generation Inc.

Email-pgoswami@sympatico.ca,

pgoswami@quickclic.net

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From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of TK, Sathyaprakash
Sent: Saturday, July 03, 2010 3:30 AM
To: materials-welding@googlegroups.com
Subject: [MW:5836] PMI using Spectroscopr JR on SDSS(F53) flanges

One of our flange vendors have used Sptroscope JR  for performing PMI on SDSS (ASTM A182 F53) flanges.

It is violating two of our requirements

1.       Our purchase requisitions wants vendor to remove any PMI marks before supplying the items to us, vendor did not comply

2.       Our construction specification  allows us only XRF machines for PMI, we did not take this into consideration while approving vendor’s  PMI procedure.

 

Vendor has advised the marks shall only be removed by grinding and their pickling and passivation which was shown as the last stage in the manufacturing ITP was not able to remove the marks.

 

Now that the items are at our site Please advise

1.       If there is any adverse metallurgical effect on the SDSS material because of the sparking on the surface?

2.       We have tried removing the spark marks by touching it by pencil grinder and is getting removed is that advisable?

 

 

Regards,

Sathyaprakash

 

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