Abstract: The toughness of pipeline materials, particularly in fracture toughness, is important for assessing the fitness-for-service of pipelines. With the advent of ultra-high resolution inline inspection (ILI) tools, the demand for fracture toughness data has risen. Current approaches to obtain fracture toughness include performing cutouts and destructive testing, leveraging existing databases, and nondestructive evaluation (NDE). A previous PPIM paper (Huang, et al., 2024) [1] demonstrated an innovative NDE method called planing-induced microfracture and validated the method for estimating fracture toughness using a lab prototype that splits a sample into two halves. Based on this successful validation, a portable field tool, Blade Toughness Meter (BTM), has been developed. The field instrument is a significant advance as it directly attaches to a pipe to perform surface preparation and surface testing in-situ. The instrument first creates raised testing surfaces by machining called “islands” on the pipe surface and then planes these islands with specially designed blades with a central opening. A true microcrack forms within the central opening, and fractured ligaments left on the chip and substrate are scanned. This paper focuses on describing the material response during the test as it relates to the fracture toughness property. The fracture surfaces examined using a scanning electron microscope (SEM) show increasing ductility features as toughness increases. The laser scanning data from these fracture surfaces show direct correlation to toughness. With these recent findings, the analytics to provide toughness results are being developed and blind-tested.
