[MW:12596] RE: 12590] CVN Impact test on 304L 2.77mm thick B31.3 piping

Hi Amit,

ASTM A-370,or ASME SA-370  allows impact test on subside specimens.If you look at Fig-12, A/SA-370 the smallest allowable thickness is 2.5 mm.Table-9 provides the acceptance criteria for various sub size specimens.

You client is right , minus(-) 269 deg C is the ultimate for any material. Although austenitic S.S is generally though to have sufficient DBTT values at this temperature, it's better to prove the same, during fabrication.

B-31.3 concerns are generic, it specifies that impact is not required if the width at the notch is less than 2.5 mm.But the discussion of B-31.3 does not address such low MDMT as -269 Deg C.

If  you have the Mill supplied MTR TESTED AT -269 DEG c ? and the MTR of  welding consumables impact tested @ -269 Deg C, then your client may have some backup document for acceptance.

Thanks.

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist & Consultant
Ontario,Canada.
Email-pgoswami@sympatico.ca,
pgoswami@quickclic.net

-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com]
Sent: Friday, September 30, 2011 1:05 PM
To: Materials & Welding
Subject: [MW:12590] CVN Impact test on 304L 2.77mm thick B31.3 piping

Please I need your assistance:-

I have Helium gas Pipeline 304L to be welded by ER308L ,having MDMT at -269 Degree Centigrade , but the thickness of my Pipe is 2.77mm , Which is exempted from the impact requirements from B31.3 Chapter-III, Table323.2.2 Column B, B-4, Notes -6, Impact test are not required when maximum obtainable charpy specimen has a width along the notch of less than 2.5mm. but my client is not ready to accept that condition/constraint of B31.3. he needs explanation that How the material thickness(2.5mm) will bear that MDMT at -269 Degree Centigrad., even Obtainable charpy specimen is not possible, but How to convince the client the material will have the properties at that temperature.

Thanks & Regards
Posting on behalf of: Amit Pahuja

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