Indian Welding Journal

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Challenges Involved in Qualifying Butt Weld of Dissimilar Materials and Dissimilar Thicknesses for Subsea Connectors System


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1 Aker Powergas Subsea Pvt Ltd, Hinjewadi, Pune – 411057, India
     

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This paper describes the challenges encountered during qualification of butt welds of dissimilar materials and dissimilar thicknesses for diverless subsea Tie-in-connection systems. These connections are designed for flowlines, umbilical and jumper spools for a temperature range of: -22° to + 135°C, and for a pressure range of 138 bar to 371 bar, and operating at a depth of 240m.

To achieve the minimum required strength of the welded joint configuration, tapered weld joint with a taper angle of 14°7' was selected. The specimen could have failed in conventional tensile testing. The problem was overcome by using the as welded geometry for tensile testing.

Establishment of technique for performing UT of dissimilar thickness&material weld joint was a challenge. Technique for UT was established by preparing a new reference block of same material and dimensions. For this complex welded joint, special probes were used to perform UT.


Keywords

Welding, Dissimilar Welding, Under Water Application, Testing.
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  • DNV-OS-F101:2010 - Submarine Pipeline Systems

  • C. D. Lundin, "Dissimilar Metal Welds - Transition Joints Literature Review", 1982

  • Barry Messer, Shawn Seitz, Doug Roth, "Selection of dissimilar metal welds in severe environments for today's petrochemical plants" 2007

  • T. W. Nelson, J.c. Lippold & M. J. Mills, "Nature and evaluation of the fusion boundary in ferritic-austenitic dissimilar metal welds" Part 2,2000

  • ASMEB31.3 - Process Piping.

  • ASTM E370 - Standard Test Method and Definitions for Mechanical Testing of Steel Products.

  • ISO 15156 - Petroleum and natural gas industries Materials for use in H2S-containing Environments in oil and gas production

  • ISO 17636-1 - Non-destructive testing of welds Radiographic testing - Part 1

  • ISO 17640 - Non-destructive testing of welds Ultrasonic testing - Techniques, testing levels, and assessment


Abstract Views: 390

PDF Views: 9




  • Challenges Involved in Qualifying Butt Weld of Dissimilar Materials and Dissimilar Thicknesses for Subsea Connectors System

Abstract Views: 390  |  PDF Views: 9

Authors

Vijay Tayade
Aker Powergas Subsea Pvt Ltd, Hinjewadi, Pune – 411057, India
Milind Darje
Aker Powergas Subsea Pvt Ltd, Hinjewadi, Pune – 411057, India

Abstract


This paper describes the challenges encountered during qualification of butt welds of dissimilar materials and dissimilar thicknesses for diverless subsea Tie-in-connection systems. These connections are designed for flowlines, umbilical and jumper spools for a temperature range of: -22° to + 135°C, and for a pressure range of 138 bar to 371 bar, and operating at a depth of 240m.

To achieve the minimum required strength of the welded joint configuration, tapered weld joint with a taper angle of 14°7' was selected. The specimen could have failed in conventional tensile testing. The problem was overcome by using the as welded geometry for tensile testing.

Establishment of technique for performing UT of dissimilar thickness&material weld joint was a challenge. Technique for UT was established by preparing a new reference block of same material and dimensions. For this complex welded joint, special probes were used to perform UT.


Keywords


Welding, Dissimilar Welding, Under Water Application, Testing.

References





DOI: https://doi.org/10.22486/iwj%2F2017%2Fv50%2Fi1%2F137779