Application of Electron Backscatter Diffraction (EBSD) on Facet Crystallographic Orientation Studies in Arctic Steels

摘要

Thick-walled high strength line pipes are being increasingly used forhigh-pressure pipeline operations to improve the transport efficiencyfor natural gas and oil. As an added challenge, pipeline constructionfor natural gas and oil transport is sometimes taking place in severeenvironments such as in the Arctic. Thus, the line pipe must have lowtemperaturetoughness together with high tensile properties. In thiswork, a study of the relationship between the brittle to ductile transitiontemperature and the microstructure in HAZ was carried out by applyingresistant heating weld simulation. The main purpose of the work was toidentify the crystallographic orientation of the cleavage facets in thefracture surface with respect to the rolling direction of the steel. Thesteel selected for this study is API X80 grade. The application ofelectron backscatter diffraction (EBSD) provided a method forinvestigating the crystallography of the fracture facets. The resultsreveal that the crystallographic indices of the cleavage crack planeswere identified to be (001), (110), (211) and (310).