Characterization of Modern High Toughness Steels for Fracture Propagation and Arrest Assessment- Phase II

Main Objective

The continuation of the project in Phase II will finalize the three-dimensional constitutive model and prepare that model to be input into the structural model of the medium scale test geometry. A ductile running crack is preceded by a large plastic process zone, and knowing the material properties of steel in the process zone, the structural model can be used to predict whether a running crack would have sufficient driving force to propagate. The objective in this phase will be to determine the material properties of the steel in the process zone and inform the constitutive model. The scope for this effort will only include X70 to meet funding and schedule needs.

Public Abstract

The development of high toughness linepipe materials is reducing the relevance of current material test methods and their application to design. Current fracture mechanics models, plastic collapse schemes and test methods are inadequate to determine the crack arresting capacity of a particular steel alloy/linepipe component. Furthermore, relatively inexpensive tests that are quick to perform are simply not available to accurately assess the fracture behavior of today's high strength and high toughness linepipe steels.