Re: [MW:35505] Re: Clarification on SS304 Pipe EFW and RF Pad Weld Alignment per ASME Standards

Dear Mr. Vinoth,

Aligning the Extruded Finned Weld (EFW) seam of a pipe with manually welded seam of RF pad in the 

same straight line is generally not recommended as per ASME standards. 

ASME B31.3 and ASME Sec. VIII do not explicitly prohibit it, they emphasize avoiding stress concentration 

points that could lead to failure.

Playing both seams in alignment may create a weak point, increasing a likelihood of crack initiation or failure 

under stress, cyclic loading or thermal expansion.  

Closely aligned seams can make NDE more challenging and may miss incomplete fusion or other defects.

ASME B31.3 (sec. 328.5.4) recommends seams should be staggered to avoid stress risers.

A good engineering practice is to maintain  a 50 mm staggering of the seams based on service conditions and 

material. 

Hence,

1. Off set the seams to minimise the stress concentration.

2. Perform RT, UT, PT to verify the weld integrity if alignment (maintaining the minimum distance) is not possible.

3. Industrial standard recommends a min. of 50 mm or 1.5 to 2 times  the thickness of pipe seam and the RF 

    pad weld for separation to reduce stress concentration. 

4. Otherwise follow client requirements for exact values.

Trust it is clear.

rgds,

C Sridhar.

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On Thu, 3 Apr 2025 at 09:46, Vinoth Kanna <gvinoth43@gmail.com> wrote:

Dear Experts,

I am following up on my earlier emails regarding the alignment of weld seams on SS304 pipes and their reinforcing pads (RF pad). I have not yet received a response and would greatly appreciate your expert opinion on the matter.

To recap: Is aligning the EFW seam of the pipe with the manually welded seam of the RF pad in the same straight line acceptable per ASME standards?

Are there any minimum distance requirements between the pipe seam and the RF pad weld joint, as per the relevant ASME code sections?

Your prompt guidance would be greatly appreciated to ensure compliance with the necessary standards.

Thank you again for your time, and I look forward to your response.

Best regards,
Vinoth G

On Thu, 27 Mar 2025 at 20:23, Vinoth Kanna <gvinoth43@gmail.com> wrote:

Dear Experts,

I would like to seek clarification regarding the alignment of the weld seams on SS304 pipes and their reinforcing pads (RF pad). Referring to the attached photo, the EFW seam of the pipe and the manually welded seam of the RF pad are aligned in the same straight line.

Could you please confirm whether this is acceptable as per ASME standards? Also I would appreciate it if you could specify the relevant ASME code section and highlight if there is any minimum distance requirement between the pipe seam and the RF pad weld joint.

Your expert guidance on this matter will be highly valuable.

Best regards,

Vinoth G

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