Min ZHOU
金属学报(英文版)
The microstructures and mechanical properties of three X80 pipeline steel plates were investigated in this study. The plates were hot rolled by two stages, and cooled by three different cooling schedules to obtain different microstructures and mechanical properties. Transmission electron microscope (TEM) was used to observe the microstructure. The results indicated that the amount of polygonal ferrite (PF) and quasi-polygonal ferrite (QPF) decreased with decreasing of the finish cooling temperature (FCT), while the amount and size of M-A islands were larger. Relaxation promoted the Charpy V-notch (CVN) impact toughness at -20 ℃, but not the drop weight tear testing (DWTT) property at -15 ℃, and decreased the strength of the steel.
关键词:
Microstructure
,
mechanical properties
,
cooling schedule, relaxation
