Niobium-containing quenching and partitioning processed ultrahigh strength martensite–austenite dual phase steels

Given the strong recent interest in quenching and partitioning processed steels, we present here a study concerning niobium bearing steel with medium carbon content. The quenching and partitioning process leads to an extremely high product of tensile strength and percentage elongation approaching 38 GPa%. The contribution is a cumulative effect of martensite with tempered randomly-oriented laths, small fraction of lower bainite, and a high fraction of retained austenite.