|About this Abstract
||MS&T23: Materials Science & Technology
||Steels for Sustainable Development II
||The Relationship Between Microstructure and Mechanical Properties in the Coarse-grain Heat-affected Zone of Line Pipe Steels
||Sabyasachi Roy, Matthias Militzer, Warren J. Poole
|On-Site Speaker (Planned)
Welding of steel changes the microstructure in the heat-affected zone (HAZ). The coarse-grain HAZ (CGHAZ) is closest to the weld pool and is critical to the integrity of the welded structures, e.g. pipelines. The present work examined the microstructure and tensile properties from laboratory-simulated CGHAZ samples obtained at different cooling rates, for seven line pipe steels. The microstructures were quantified based on the density of high-angle grain boundaries (HAGBs) evaluated using electron backscattered diffraction. Furthermore, Charpy impact toughness and ductile to brittle transition temperatures were measured for a range of HAGB densities, and then linked to the microstructure. It was observed that an increase in the cooling rate for a given steel results in (1) a larger density of HAGBs and (2) an increase in tensile strength. A Hall–Petch–type relationship is proposed to link the yield strength with the HAGB density.