Effect of Boron Concentration on Dynamic Recrystallization Behavior of Low-Carbon Steel

Abstract

The dynamic recrystallization behavior of low-carbon steel containing three different amounts of boron (0.002, 0.004, and 0.006 wt%) was systematically investigated under various experimental conditions. Low-carbon steel was exposed to temperatures ranging from 900 to 1100 °C, strain rates from 0.1 to 10 s−1, and inspection of the initial austenite grain size at 1150 °C. The resulting stress–strain curves are observed to possess two classifications of behavior, dynamic recovery and dynamic recrystallization, while the initial austenite grain size increases directly proportional to boron concentration. Additionally, the characteristic points of the flow curves were analyzed by regression method in which the peak and critical stresses decreased in response to an increase in boron composition, indicating that a softening effect appears with the addition of boron. On the contrary, peak and critical strains increased as boron content increased, indicating that boron has the ability to delay the onset of dynamic recrystallization. Lastly, the kinetics model of dynamic recrystallization for three boron-treated steels was established.