The effects of intercritical annealing and subcritical tempering on the mechanical properties and corrosion resistance of mild steel were studied. It was revealed that intercritical annealing followed by quenching resulted in the development of a ferritic-martensitic dual phase (DP) microstructure with high tensile strength, disappearance of the yield-point phenomenon, superior work-hardening b...

The microstructural evolution of Fe–0.2C–5Mn steel during intercritical annealing with holding time for up to 144 hours was examined by TEM and STEM. It was demonstrated by TEM that the martensite lath structure gradually transformed into a lamellar ferrite and austenite duplex structure. The partitioning of manganese from ferrite to austenite was found by STEM. Typical Kurdjumov-Sachs orientat...

A duplex microstructure consisting of allotriomorphic ferrite and austenite at ambient temperature, has been produced in a low–alloy steel, by a simple heat treatment which involves intercritical annealing followed by quenching. The tensile properties obtained are good, with a total elongation of some 28% at an ultimate tensile strength approaching 900MPa. The form of the stress versus strain c...

Microstructures of both as-quenched and intercritical-annealed medium-Mn steel were investigated by transmission electron microscopy to acquire a better understanding ?–? ?–?? martensitic transformations. The orientation relationships among each phases determined as (1¯10)??//(0001)?,[111]??//[112¯0]? for the case sample, (1¯10)??//(1¯11)?//(0001)?,[111]??//[110]?//[112¯0]? respectively. In add...

Dual phase (DP) steels are rapidly becoming more and popular for automotive applications. They offer a weight reduction with combination of energy absorption crash zones. Rails, reinforcements, back panels, cross members, pillars can be given as application examples. DP microstructure consists soft ferrite matrix hard martensite islands. The islands provide strength while the ductile provides f...

A quantitative and automated phase analysis of dual-phase (DP) steel using electron backscatter diffraction (EBSD) was attempted. A ferrite-martensite DP microstructure was produced by intercritical annealing and quenching. An EBSD map of the microstructure was obtained and post-processed for phase discrimination. Band slope (BS), which was a measure of pattern quality, exhibited much stronger ...