Nb-Microalloying in Next-Generation Flat-Rolled Steels: An Overview

Abstract:

Extensive efforts are underway worldwide to develop new steels with substantial fractions of retained austenite, for lightweight automobile manufacturing and other applications requiring improved combinations of strength and formability. It is likely that microalloying can provide product enhancements in these emerging products, such as Q&P, TBF, medium-Mn TRIP, etc. and this paper examines the expected behavior of niobium using inferences based on published AHSS literature and principles of Nb microalloying. Some benefits of Nb in terms of microstructure refinement and precipitation strengthening have been reported. The potential influences of Nb are complex due to the sensitivity of Nb dissolution and precipitation to chemical composition and processing; differences in the expected role of Nb are pointed out with respect to different product forms produced via hot-rolling or annealing after cold-rolling, and microstructures with or without substantial quantities of primary ferrite. Some issues that warrant further examination are identified, as a deep understanding of Nb microalloying and other fundamental behaviors will be needed to optimize the performance of these next-generation steels.

• Periodical: Materials Science Forum (Volume 879)
• Pages: 1834-1840
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.879.1834
• Online since: November 2016
• Authors: John G. Speer*, Ana L. Araujo, David K. Matlock, Emmanuel de Moor
• Keywords: Microalloying, Niobium, Partition, Plate, Q&P, Quench, Retained Austenite, Sheet, Steel

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