Effect of Heating Rate on the Kinetics of Austenite Formation in Low-carbon High-strength Steels Annealed in the Intercritical Region

摘要

Austenite formation during intercritical annealing was studied in a low-carbon dual phase steel. Different heating rates, annealing temperatures, and holding times were applied to determine their effect on the kinetics of austenitization. The effect of these process parameters on the final microstructures and mechanical properties were also investigated using a fixed cooling rate after corresponding annealing treatment. It was found that heating rate affects austenite formation kinetics during both continuous heating and following isothermal holding and the effect is more pronounced at lower temperatures. It was found that heating rate and temperature of intercritical annealing have a stronger effect on the tensile strength of the steel than to the holding time. Both high annealing temperatures and long holding times minimize the strength difference caused by a variable heating rate.