PR350-214509-R01 Test Options for Enhanced Welding Procedure Qualification

There have been a number of notable girth weld failures in newly constructed pipelines in North America, Asia, and South America. The primary contributors to the North America incidents have been identified as (1) weld strength undermatching, (2) heat-affected zone softening, and (3) elevated stress-strain in the affected girth welds. This project is a continuation of previous PRCI supported work and JIP with a particular focus on addressing the first two contributors through enhanced girth welding procedure qualification.

Three test options for enhanced welding procedure qualification are proposed, including

– All-weld-metal tensile (AWMT) test,

– Non-instrumented cross-weld tensile (CWT) test, and

– Instrumented cross-weld tensile (ICWT) test.

These test options are intended as supplemental requirements to the qualification requirements in applicable standards. Adding some of the test options and associated acceptance criteria in welding procedure qualification should minimize the possibility of excessive weld strength undermatching and HAZ softening, thus leading to production welds having greater strain tolerance than that could be achieved without such tests.

It is recognized that adding additional tests and qualification requirements can increase the complexity of welding procedure qualification processes. However, adding at least one of the test options is necessary to minimize the possibility of low strain failures of girth welds in newly constructed pipelines, including CO2 and H2 pipelines. The pipeline industry can benefit from enhanced safety and public trust.