Experience of P93 manifold welding under fabrication conditions

ABSTRACT

A test manifold of grade P93 is welded under shop fabrication conditions. Raw materials include pipe and forgings. Welding processes used are GTAW and SMAW. Weld joints involve heavy wall butt welds and branch joints. Welded joints are subjected to different heat treatment cycles to assess the effect on the materials’ properties. Welding experiences and mechanical test results in relation to PWHT and ageing are discussed. Tensile test results comply with the requirements. Achieving impact toughness requirements appears to be challenging, however improvements are expected through further optimisation of heat treatment and welding procedures.

KEYWORDS:

• Grade P93
• welding
• mechanical properties
• thermal ageing

Acknowledgments

We like to thank Dr. T.U. Kern from Siemens-Energy Global GmbH & Co. KG, Germany, for his support and providing the data on the ageing tests.

Disclosure statement

No potential conflict of interest was reported by the author(s).