Microstructural and mechanical properties development during quenching-partitioning-tempering process of Nb-V-Ti microalloyed ultra-high strength steel

The applicability of quenching–partitioning–tempering (Q-P-T) treatment to the Nb–V–Ti microalloyed ultra-high strength steel has been investigated by SEM, TEM, XRD examination and mechanical tests. After Q-P process, lath martensite and retained austenite were obtained. Three kinds of carbides have been identified, namely Ti-rich MC, Nb-rich MC and M3C. In addition to tempered martensite and retained austenite, M2C, M7C3 and M23C6 particles...