Processing and Properties of Niobium Microalloyed High Strength Quenched and Tempered Structural Steel Plates

摘要

High strength structural steel plates with yield strength values up to 690 MPa and above are typically manufactured by quenching and tempering. The influence of niobium (Nb) microalloying in Quenched and Tempered (Q&T) steel plates are reviewed in this article. Niobium microalloying can significantly improve the strength and toughness of the final plate product ifThermo-Mechanical Controlled Rolling (TMCR) process is adopted during hot rolling. Direct quenching of plates after finish rolling offers further improvement in mechanical properties because, some quantity of niobium in the plate may still be in solution during quenching, thus increasing the hardenability of the plate during quenching and offers potential for precipitation hardening during tempering.