Fine-grained dual-phase steels fabricated via cold-rolling ferrite-martensite structure and subsequent intercritical annealing

Abstract

A proposed alternative method for processing dual phase (DP) steels is the utilization of a cold-rolled duplex ferrite-martensite structure, followed by intercritical annealing. The obtained results demonstrate the feasibility of this approach in producing a desirable microstructure. The microstructure consists of ferrite grains with an average size of less than 6 μm, along with a uniformly distributed fine martensitic phase. Treatment of the steels using this alternative route results in improved strength-ductility properties and a greater work-hardening exponent. These steels exhibit an excellent combination of mechanical properties with tensile strength of 866.69 MPa, total elongation of 24.40%, and the product of tensile strength and total elongation of exceed 20 GPa%.