Coherent Sour Toughness Testing Across NACE Regions: Data Analysis Across Multiple Projects, Sources, and Environments With Guidance to Consistently Measure Meaningful Lower Bound Toughness Results

Abstract Sour fracture performance of line pipe steel and welds is a critical input for projects that are designed for sour production environments. Challenges with characterizing a materials fracture response in sour environments are numerous, with both limited global testing resources and sensitivity of the test outcome to test variables. As no codified test procedure currently exists for sour service fracture toughness testing, industry projects often rely on historical experiences of the specific test labs while trying to achieve results that align with project timelines. Understanding the factors that impact toughness results along with ensuring consistent execution can play a crucial role in project success. In this paper, we study a database of sour fracture toughness tests spanning 14 projects over 10 years with the goal improving efficiency and consistency in sour fracture toughness testing. The database is analyzed to demonstrate various relationships between sour toughness testing parameters. Testing guidance is provided regarding specimen type, thickness, coating, loading rate, soak time, and notch location. The provided guidance will simplify and shorten most sour toughness testing programs. The presented analysis also provides the type of information needed to make informed decisions regarding sour fracture toughness across NACE regions earlier in project design.