L52336 Weld Design Testing and Assessment Procedures for High-strength Pipelines Curved Wide Plate Tests

A variety of mechanical property tests are performed in the design, construction and maintenance phase of a pipeline. Most of the tests are performed by use of small-scale specimens with size typically in the range of a few inches to tens of inches (1 in = 25.4 mm). There are numerous test labs capable of performing most small-scale tests. These tests can be performed effectively under a variety of conditions, e.g., test temperature, strain rate, and loading configuration. More importantly, most routine small-scale tests are performed in accordance with national and international standards, ensuring the consistency of testing procedures.

To confirm pipeline designs and validate material performance, it is desirable to test girth welds under realistic service conditions. Full-scale tests can incorporate certain realistic features that small-scale specimens cannot. However, these tests can be time-consuming and expensive to conduct. Very few labs can perform the tests, even with months of start-up and preparation time. There are no generally accepted, consistent test procedures among different test labs. The data acquisition and post-processing may differ from lab to lab, creating difficulties in data comparison. Full-scale tests can only be performed under selected conditions as a supplemental tool to the small-scale tests.

The work described in this report focuses on the development of test procedures and instrumentation requirements for curved-wide-plate (CWP) tests. The results of this work can be used for:

Developing a test methodology to measure the physical response of a finite-length surface-breaking flaw to axial loads applied to a girth welded line pipe section,
Determining the appropriate instrumentation to fully characterize the global stress/strain response of the CWP specimen during loading,
Evaluating the applicability of the test methodology for sub-ambient temperatures, and
Developing a standardized test procedure for CWP testing with a wide range of test parameters.