Dear Mr. Pradip,
The straight forward answer is - There is no acceptance criteria in ASME B 31.3 for root oxidation for category M fluid.
No code has identified it is as a defect and so called acceptance / rejection criteria not defined. However, process licensor / consultants have defined various criteria for oxidation of the weld based on expected corrosion resistance of the weld.
In fact, this has been considered as inherent control of a welding process .Weld gets oxidised due to inadequate / improper shielding or contaminated shielding gas. So first remedial action would be to provide the condition, which eventually will results in proper shielding of the weld joint.
Further , when weld gets oxidised, there may be detrimental effect on the weld metal properties. For procedure qualification, the oxidised weld results in failure of bend test also. These oxide layers may be removed by mechanical grinding / pickling passivation etc.
For low and moderate corrosion, for stainless steel, heat tint upto yellow is acceptable. For severe corrosion conditions, the bright shinny (no discoloration) weld is required.
I fully agree with Mr. Vagal's opinion, regarding acceptance standard as WPS to minimum. However, process licensor / consultants recommendations to be followed for rejection of the weld.
With Best Regards,
Jignesh R Rana
Manager - Materials Technology, QA/QC & Standards+
Linde Engineering India Pvt. Ltd.
'Linde House'
Opp: VUDA Office, VIP Road, Karelibaug,Vadodara - 390018, India.
Tel.: +91 265 3056789, Fax: +91 265 2335213 , Mobile: +91 90999 86019
jignesh.rana@linde-le.com, www.linde-india.com
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Shashank Vagal ---05/31/2012 10:50:20 AM---Such welds will be rejected for having failed to meet WPS requirements, to say the least. --- On Wed
From: Shashank Vagal <nach_sam@yahoo.com>
To: materials-welding@googlegroups.com
Date: 05/31/2012 10:50 AM
Subject: Re: [MW:14425] Acceptance criteria for root oxidation
Sent by: materials-welding@googlegroups.com
| Such welds will be rejected for having failed to meet WPS requirements, to say the least. --- On Wed, 30/5/12, pradip kumar sil <pradipsil@gmail.com> wrote: From: pradip kumar sil <pradipsil@gmail.com> Subject: [MW:14419] Acceptance criteria for root oxidation To: materials-welding@googlegroups.com Date: Wednesday, 30 May, 2012, 11:59 PM Dear experts, As per ASME B 31.3 what is the acceptance criteria for the root oxidation in M catagory fluid. Thanks in advance. Regards Pradip -- To post to this group, send email to materials-welding@googlegroups.com To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com For more options, visit this group's bolg at http://materials-welding.blogspot.com/ The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents. |
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The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
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