Mechanical properties of dual-phase steel with long, fibrous martensite

Dual-phase steel with long fibrous martensite was obtained by rolling at the intercritical annealing temperature after different annealing times. The high strength and low ductility of the as-rolled steel are caused by the fibrous nature of the martensite and by work-hardening during the latter stages of rolling depending on the finishing rolling temperature. Annealing can improve the ductility through recrystallisation and also by changes to the martensite morphology. The as-rolled steel shows two distinct work-hardening processes with different exponents, whereas a single exponent can describe the work-hardening of the annealed steel.