High-efficiency fast-heating annealing of a cold-rolled dual-phase steel

• Fast-heating annealing process was applied to dual-phase steels.
• Improved mechanical properties were obtained in fast-heating processed DP steel.
• Strong interaction between ferrite recrystallization and austenite formation occurs.
• Fast-heating process demonstrates potential for industrial production.

In the present work, fast-heating annealing was performed on a cold-rolled Fe–0.07C–1.7Mn–0.429Si dual-phase steel. In contrast to commercial conventional continuous annealed steel, 6.6% higher ultimate tensile strength and 14.1% greater elongation were obtained. Transmission electron microscopy observations reveal the incomplete ferrite recrystallization, the formation of bainite and fine fiber-like martensite in fast-heating processed dual-phase steel. High-efficiency simplified fast-heating annealing process demonstrates great potential for large-scale production.