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Microstructure and Thickness Effects on Impact Behavior and Separation Formation in X70 Pipeline Steel

Published

Author(s)

Emily B. Mitchell, Enrico Lucon, Laurie E. Collins, Amy J. Clarke, Kester D. Clarke

Abstract

In an effort to optimize the transportation of oil and gas, the pipeline industry is developing large diameter, thick-walled pipelines that can withstand low temperatures and high pressures. In this study, three American Petroleum Institute grade X70 steel plates of similar chemistry, ranging in thickness from 13.5 mm-22 mm, were subjected to drop-weight tear and Charpy V-notch tests to determine the effects of plate thickness and microstructure on the formation of separations and on impact behavior. The severity of separations was generally dictated by constraint imposed by drop-weight tear test specimen thickness, and microstructural banding was not found to promote separation formation, but the three microstructures exhibited different separation behavior. Separations were observed most frequently when the fracture plane was parallel to the rolling direction. This study also found that previously developed empirical relationships between Charpy V-notch and drop-weight tear tests appear to no longer apply to the type of advanced high strength and toughness steels investigated.
Citation
JOM Journal of the Minerals Metals and Materials Society

Citation

Mitchell, E. , Lucon, E. , Collins, L. , Clarke, A. and Clarke, K. (2021), Microstructure and Thickness Effects on Impact Behavior and Separation Formation in X70 Pipeline Steel, JOM Journal of the Minerals Metals and Materials Society, [online], https://doi.org/10.1007/s11837-021-04562-9, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=928885 (Accessed May 18, 2024)

Issues

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Created April 5, 2021, Updated October 12, 2021