Fig. 13.4 Transverse cross section of a dual-phase steel containing C = 0.09%, Mn = 1%, and Nb = 0.03%. Ferrite (F) and martensite (M). Ferrite grain size: 5 μm. Etchant: nital. SEM, SE. Courtesy of ArcelorMittal Tubarão, ES, Brazil. More

Fig. 13.5 Transverse cross section of a dual-phase steel containing C = 0.09%, Mn = 1%, and Nb = 0.03%. Ferrite (F) and bainite (B), with some pearlite (P). Ferrite grain size: 3 μm. Etchant: nital. SEM, SE. Courtesy of ArcelorMittal Tubarão, ES, Brazil. More

Fig. 13.6 Dual-phase steel. Ferrite and some martensite areas with retained austenite. Etchant: nital 4% followed picral 4%. Courtesy of ArcelorMittal Tubarão, ES, Brazil. More

Fig. 13.13 Equilibrium austenite volume fraction for the dual-phase steel in Fig. 13.11 . The experimentally measured Ac 1 and Ac 3 are included. For 7 °C and 60 °C/s (13 °F and 110 °F/s) the transformation temperatures did not change significantly. Source: Ref 6 More

Fig. 13.14 (Part 1) Microstructural evolution of a dual phase steel hot rolled, cold worked, and subjected to austenitization inside the critical zone for the times and temperatures indicated in (a), (b), and (c). Etchant: LePera. Martensite: light; ferrite: gray; pearlite: dark. (d), (e More

Fig. 13.14 (Part 2) Microstructural evolution of a dual phase steel hot rolled, cold worked, and subjected to austenitization inside the critical zone for the times and temperatures indicated in (a), (b), and (c). Etchant: LePera. Martensite: light; ferrite: gray; pearlite: dark. (d), (e More

Fig. 7.12 Microstructure of a dual-phase steel sheet showing the results of deformation by shearing. (a) Correct dual-phase microstructure away from the shear burr. (b) Shear burr region where pools of retained austenite have transformed to martensite by the plastic deformation. Arrows More

Fig. 8.18 A dual-phase steel showing epitaxial ferrite (new ferrite) at prior austenite grain boundaries. The epitaxial ferrite formed when the steel was heated into the two-phase region. Austenite formed at the grain boundaries, and ferrite transformed epitaxially on the old ferrite upon More

Fig. 8.36 Epitaxial ferrite in a dual-phase steel. The epitaxial ferrite is surrounding regions of martensite (dark-appearing constituent) (see arrows). Matrix is ferrite. Sodium metabisulfite tint etch. 1000× More

Fig. 12.16 Schematic diagram that illustrates dual-phase steel processing (dashed line) to produce ferrite (F)-martensite (M) microstructures and TRIP steel processing (solid line) to produce ferrite-bainite (B)-austenite (A) and martensite microstructures after intercritical annealing. Source More

Fig. 12.18 Dislocation substructure in a 0.06% C-Mn-Si dual-phase steel intercritically annealed at 810 °C (1490 °F) and cooled at 60 °C/s (110 °F/s). (a) High dislocation density in ferrite adjacent to a martensitic area (black) and (b) in ferrite removed from martensitic areas. Transmission More

Fig. 1.8 Micrograph of AISI DF090T dual-phase steel showing a microstructure consisting of ferrite (light etching constituent) and a small amount of martensite (dark etching constituent). Etched in 4% picral. 500× More

Fig. 3.9 Microstructure of a typical dual-phase steel bar consisting of martensite (dark) in a matrix of ferrite (light). 2% nital etch. 1000× More

Fig. 20.16 Microstructure of dual-phase steel. Source: Ref 17 More

Fig. 5.6 Temperature changes during continuous annealing of dual-phase steel sheets. M s , martensite start temperature. Source: Ref 5.3 More

Fig. 5.7 Continuous annealing line process for producing coated dual-phase steel. F, ferrite; B, bainite; P, pearlite; M, martensite. Adapted from Ref 5.6 More

Fig. 7-24 Microstructure typical of those of dual phase steels. The steel contained 0.06% C and 1.5% Mn and was water quenched from 760°C. (Adapted from G.R. Speich, in Fundamentals of Dual-Phase Steels , The Metallurgical Society, Warrendale, PA (1981), Ref 10 ) More

Fig. 13.16 Engineering stress-strain curves of three grain sizes of dual-phase steels. UFG, ultrafine grain; FG, fine grain; CG, coarse grain; d f , ferrite grain size. Source: Ref 13.8 More