Effect of Cooling Rate on the Precipitation Behavior of Κ-Carbide in Fe-32Mn-11Al-0.9C Low Density Steel

The effect of cooling rate on the precipitation behavior of κ-carbide in Fe-32Mn-11Al-0.9C low density steel was studied using thermal expansion measurements during continuous cooling process. The results show that κ-carbide starts to precipitate at the γ/δ interface as the cooling rate decreases to 3 ℃/s. With a decrease in cooling rate, the content and size of κ-carbide precipitations increases significantly. The nanohardness of austenite slightly decreases with increasing the cooling rate while that of δ-ferrite significantly increases owing to κ-carbide precipitation hardening at the γ/δ interface.