A Systematic Material Evaluation Program for High Grade Line Pipe Materials

TransCanada Pipelines has decades of experience in both research and application of high grade materials in its pipeline systems. This evolution process has led to a unique way for the company to understand and evaluate high grade materials including X80, X100 and X120. As part of its pipeline construction quality management system, TransCanada has launched a systematic material evaluation program that, in addition to its pipe material specifications which were built on top of relevant CSA standards, specifies procedures for qualification and evaluation of line pipe materials. Consequently, a multi-tiered pipe material quality control system is established. The material evaluation program consists of both management procedures and technical procedures. This paper is to present the framework and the major components of the technical procedure. Due to the specific mechanical properties of high grade line pipe materials and their specific features of applications, material testing matrix is defined to evaluate not only the pipe body material but also girth welds made with modern pipeline welding technologies. For X80 pipes, while the program is concentrated for material qualification based on stress-based design requirements, a “further look” into the material properties is taken to evaluate the suitability of the pipe products to be applied under strain-based design conditions. For X100 and higher grade pipes, a full research test matrix is defined to explore the applicability of the material in strain-based design conditions, particularly the northern development design conditions.