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Outline

Procedure qualification requirementsin API 1104 vs. other internationalcodes and standards

Specification of supplementalrequirements

Manual welding options for“susceptible” line pipe material

– Example of wide, tall cap passtechnique

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Procedure Qualification Requirements

For girth welds assessed using workmanship-based acceptance criteria, there is no requirement in API 1104 for the actual strength of the weld to be greater than the actual strength of the pipe material– Cross-weld tensile specimens are allowed to break in the weld as long as they do so above

the specified-minimum tensile strength of the pipe material

In addition, there is no requirement to qualify (or otherwise test) the welding procedure on “project pipe”– It is only necessary to use a procedure that was qualified on the appropriate grade of pipe

(same grade or highest grade within a group)

– Different pipe materials of the same grade can have widely different tensile properties depending on when they were made, the method of manufacture, by whom they were made, etc.

For many applications (e.g., pipelines in non-flat terrain), it is good practice to at least match the actual yield strength of the project pipe

The requirements in many other international codes and standards for pipeline girth welding simply mirror those in API 1104

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Review of Other International Codes and Standards

Tensile testing requirements in the following codes and standards were reviewed and compared with API 1104:

– CSA-Z662-19 – Oil and gas pipeline systems

– BS 4515-1 – Specification for welding of steel pipelines on land and offshore -Part 1: Carbon and carbon manganese steel pipelines

– ISO 13847 – Petroleum and natural gas industries - Pipeline transportation systems - Welding of pipelines

– AS2885.2:2016 – Pipelines - Gas and liquid petroleum. Part 2: Welding

– ASME Section IX – Welding, Brazing, and Fusing Qualifications

Only AS2885.2 requires procedure qualification on project pipe

All allow tensile test specimens to break in the weld if they do so above the specified-minimum tensile strength of the pipe material (or 95% thereof)

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Supplemental Requirements

Just because these industry codes and standards allow the actual strength of the weld to be less than the actual strength of the base material does not mean that this is good practice– The use of good engineering judgement is critical

– User must choose what acceptance criteria is appropriate for a given application, which may be over-and-above the minimum requirements

For large diameter pipelines constructed using modern high strength line pipe materials, supplemental requirements should be incorporated into construction contract documents that require:– Welding procedures to be qualified (or

demonstrated) on project pipe and

– Acceptance criteria for cross-weld tensiletesting should be failure of the specimens inthe base material away from the weld

Particularly for pipelines in hilly terrain orsubject to subsidence or other forms ofground deformation

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Manual Welding Options for “Susceptible” Line Pipe Material

Cellulosic electrodes in conjunction with a wide, tall cap pass

– Seen as a stop-gap measure

LHVD (e.g., E9045 or E10045) electrodes for fill and cap passes

– Seen as a longer term solution

– Can actually result in an increase in productivity over the use of cellulosic-coated electrodes

E8010 electrodes for root pass welding (as opposed to E6010) can also contribute to producing overmatching strength

– Particularly for thinner wall line pipe

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Example of Standard Cap vs. Taller, Wider Three-bead Cap –36 inch diameter by 0.476 inch wall thickness

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Example of Bead Sequence and Dimensions of Wide, Tall Cap Pass

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Amount of offset required for the first bead of a wide, tall three-bead cap - 0.476 inch wall thickness

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Macrograph taken from Weld with Wide, Tall Cap

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Project Specific Go/No-go Gauge for Verifying Cap Height and Width

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Bend Test Specimen that Exhibits Undermatching Strength Weld Metal

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Cross-weld Tensile Specimens and Bend Test Specimens that Illustrate Matching Strength

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