Influence of Chemical and Processing Variables on Annealing Response of Cold-Rolled Microalloyed Steels
While effects of aluminum on the properties of vanadium microalloyed steels have been recognized in the past, recent work by Garrison et al. reported an interesting competition between vanadium and aluminum for nitrogen in steels. Aluminum variations were found to influence the mechanical properties of vanadium microalloyed sheet steels in both the hot-rolled condition, as well as after subsequent cold-rolling and annealing (including both batch and continuous annealing processing simulations). Because of the “apparent competition” between aluminum and vanadium for the available nitrogen, a reduced level of aluminum was associated with higher strength levels. Recrystallization during annealing after cold rolling was also suppressed in the low-aluminum steel based on the observed microstructure and property responses to continuous annealing over a range of temperatures. These behaviors were believed to be due to aluminum effects on vanadium carbonitride precipitation strengthening. In the high aluminum steel, AlN was the prominent precipitate, while in the low aluminum steel, V(C, N) was prominent. It was concluded that the increase in aluminum content increases the driving force to form aluminum nitrides. AlN formation in turn decreases the amount of nitrogen in solution to combine with vanadium. Vanadium carbonitride is a potent precipitation strengthener in steels, whereas AlN is not a potent strengthener.
B. A. Blumhardt et al., "Influence of Chemical and Processing Variables on Annealing Response of Cold-Rolled Microalloyed Steels," Proceedings of the International Conference on Microalloyed Steels: Processing, Properties, Microstructure, and Performance (2007, Pittsburg, PA), pp. 277-287, Association for Iron & Steel Technology (AIST), Jul 2007.
International Conference on Microalloyed Steels: Processing, Properties, Microstructure, and Performance (2007: Jul. 16-19, Pittsburg, PA)
Materials Science and Engineering
Keywords and Phrases
Microalloy Steel; Aluminum Nitride; Vanadium Carbonitride; Niobium Carbonitride; Cold Rolling; Batch Annealing
Article - Conference proceedings
© 2007 Association for Iron & Steel Technology (AIST)