Effect of cooling rate on the microstructure and mechanical properties of a low-carbon low-alloyed steel

Abstract Heavy plate steels with bainitic microstructures are widely used in industry due to their good combination of strength and toughness. However, obtaining optimal mechanical properties is often challenging the complex multiple phase constitutions caused by different cooling rates through thickness. Here, both conventional advanced microstructural characterization techniques which bridge meso- atomic-scales were applied investigate how microstructure/mechanical property-relationships a low-carbon low-alloyed steel affected transformations during continuous cooling. Mechanical tests show that yield increases monotonically when increase up 90 K/s. The present study shows this associated decrease volume fraction polygonal ferrite (PF) refinement substructure degenerated upper bainite (DUB). fine DUB substructures feature C-rich retained austenite/martensite-austenite (RA/M-A) constitutes decorate elongated micrograin boundaries ferrite. A further observed needle-shaped cementite precipitates form water quenching within micrograins. Pure martensite islands on lead decreased ductility. implications for thick section processing discussed based findings work.