WRC 590 PDF

This Bulletin describes research that was jointly funded by the American Petroleum Institute (API) and the Welding Research Council, Inc. (WRC) in support of the joint Fitness-For-Service Standard, API 579-1/ASME FFS-1. It has been well established for several decades that the effective fracture toughness of structural components that contain crack-like flaws can be significantly higher than toughness measured on standard laboratory coupons. The reason for this effect is a relaxation in crack tip triaxiality (i.e., constraint) that occurs in component with predominately membrane loading, as well as components with shallow cracks.