Effect of cold rolling reduction on microstructure, mechanical properties, and texture of deep drawing dual-phase (DP) steel

Abstract

In this study, the microstructure, mechanical properties, and texture of deep drawing dual-phase (DP) steel subjected to different cold rolling reductions were characterized via optical microscopy (OM), scanning electron microscopy (SEM), and x-ray diffraction (XRD) techniques. The results revealed that the microstructure of the steel is composed of ferrite and a small amount of martensite after cold rolling annealing. The ferrite grain size varied only slightly with the reduction. In addition, the orientation density along the γ orientation line increased continuously with increasing cold rolling reduction ratio. Similarly, the {112}〈110〉 and {223}〈110〉 components along the α orientation line and the adjacent {554}〈225〉 and {332}〈113〉 components were strongly developed. The ratio of the {111} plane texture volume fraction to that of the {100} plane texture, i.e., V{111}/V{100}, increased initially and then decreased, reaching the optimum value at 75% reduction. The maximum strength of the steel (i.e., 430 MPa) was realized at 55% reduction. However, the best elongation and r values (29.8% and 1.46, respectively) were obtained at 75% reduction.