About this Abstract |
| Meeting |
MS&T26: Materials Science & Technology
|
| Symposium
|
Developments in Plate and Line Pipe Steels
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| Presentation Title |
Microstructure and Mechanical Properties of Weld Heat-Affected Zones in High Strength Pipeline Steels for Sour and Hydrogen Service Applications |
| Author(s) |
Lawrence Cho, Santigopal Samanta, Chen Ni, Andrew LeBoeuf, Zhenzhen Yu, Kip O. Findley |
| On-Site Speaker (Planned) |
Lawrence Cho |
| Abstract Scope |
There is a strong interest in using higher-strength pipeline steels to accommodate higher operating pressures in the oil and gas industry, including sour and hydrogen service applications. However, the impact toughness and fracture resistance of the weld heat-affected zones (HAZs) of high-strength pipeline steels are critical concerns in demanding service conditions, including hydrogen-rich environments. Industry standards commonly limit HAZ hardness to specified values to avoid localized high-hardness regions, based on the assumption that these regions may exhibit poor toughness. The present work investigates the microstructural influence on hardness, impact toughness, and gaseous hydrogen embrittlement properties of simulated HAZs in high-strength (X65 to X80) pipeline steels. In particular, bainite- and martensite-containing microstructures in HAZs exhibit significantly increased hardness and reduced impact and fracture toughness compared to the base metal. This work introduces a rapid post-weld heat treatment strategy to create HAZ microstructures with an improved balance between hardness and toughness. |