Inspectioneering
Inspectioneering Journal

Lack of Fusion on Socket Weld Joints – A Case Study

By Reynaldo J. Mejias, Mechanical Engineer/API Inspector at Chevron Phillips, and Magredt Tatiana Duran Meneses, Metallurgical Engineer. This article appears in the May/June 2023 issue of Inspectioneering Journal.
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Introduction

Inspecting welds during piping construction is a basic element of a robust QA/QC program. The minimum requirements for inspecting process piping in the petroleum and chemical processing industries are established in ASME B31.3 and other complementary codes and practices. When weld defects or discontinuities are discovered during inspection, it is critical that they are not ignored, misinterpreted, or handled the wrong way.

Socket welds are typically simpler and easier to perform than butt welds. For this reason, the importance or priority of inspection requirements for socket welds may not be taken as seriously following construction. However, complications due to low diameter, geometry, procedure, and qualification of welders have resulted in flaws being overlooked, introducing an increased potential for loss of primary containment and safety incidents.

Therefore, improving the process to clarify welding procedures, verify welder qualifications, and capture important data can improve the integrity of socket welds and help mitigate mechanical integrity risks.

Context

During a refinery turnaround, the fabrication and installation of 316 stainless steel piping was performed. After QA approval, the QC program review was in progress when an unusual issue was discovered. A trend indicating an issue with lack of fusion on socket welds was becoming increasingly evident, and after more data was gathered, it became clear that it was a widespread problem. The QC program required performing radiographic testing (RT) of over 30% of the total socket weld joint to verify that the gap requested for this type of joint per ASME 31 was achieved. After performing the first 98 RTs, 20 welds showed evidence of a common flaw -- lack of fusion in the roots.

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Comments and Discussion

Posted by Ander Lasuen on July 7, 2023
This article is confusing! Topic seems to be... Log in or register to read the rest of this comment.

Posted by Melvin Cappa on August 7, 2023
Well the RT's shows that the pipe has and show... Log in or register to read the rest of this comment.

Posted by Ryan Yang on August 7, 2023
'Lack of fusion on socket welds': weld... Log in or register to read the rest of this comment.

Posted by William MacRitchie on August 7, 2023
The latest edition of ASME B31.3 states that a... Log in or register to read the rest of this comment.

Posted by Andy Anderson on August 8, 2023
I would have certain concerns about performing... Log in or register to read the rest of this comment.

Posted by Chuck Mielke on August 8, 2023 (Edited on August 8, 2023)
Thanks for your work as this is an interesting... Log in or register to read the rest of this comment.

Posted by Ander Lasuen on August 14, 2023 (Edited on August 14, 2023)
Hi again, Lack of penetration is not a concept... Log in or register to read the rest of this comment.

Posted by DEBASIS MITRA on August 25, 2023
Hi, This is an interesting discussion as well a... Log in or register to read the rest of this comment.

Posted by Chuck Mielke on August 28, 2023 (Edited on August 28, 2023)
Thank you for your input as it has been an... Log in or register to read the rest of this comment.

Posted by Ryan Yang on August 28, 2023
The recent ASEM B31.3-2022 Process Piping Errata... Log in or register to read the rest of this comment.

Posted by DEBASIS MITRA on August 28, 2023
Dear Chuck, Good day, Lets make the discussion... Log in or register to read the rest of this comment.

Posted by Omar Alqurashi on September 4, 2023
I am not Inspection matter expert, however i have... Log in or register to read the rest of this comment.

Posted by Ramakrishna Dadi on September 8, 2023
As per the profile RT of small bore inspection... Log in or register to read the rest of this comment.

Posted by DEBASIS MITRA on September 9, 2023
Dear all, Discussions should help all global... Log in or register to read the rest of this comment.

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