Effect of Microstructure and Texture Evolution During Variable Gauge Rolling on Mechanical Properties of Tailor Rolled Blanks

In this study, anisotropic elastic and plastic mechanical properties of a tailor rolled blank (TRB) with thickness ratio of 0.52 (1 mm/1.9 mm), have been fully studied. To gain a deeper insight into anisotropic mechanical behavior of the studied TRB, continuous changes in microstructure and crystallographic texture of a dual phase steel caused by variable gauge rolling (VGR) were investigated on several points (on RD–ND plane) along longitudinal direction with the aid of EBSD observations. Analysis of grain boundary (GB) maps revealed that ferrite grain refinement is occurred during VGR so that the average ferrite grain size decreases from 4.1 µm for the thicker side to 2.2 µm for the thinner side. Furthermore, it was found out that substructure density is more intense within smaller ferrite grains. Evaluation of inverse pole figures as well as orientation distribution function maps showed that texture of thicker side comprises {001}〈110〉 and {112}〈110〉 components along \( \alpha \)-fiber. In addition, it was revealed that orientations of {111}〈110〉 and {111}〈112〉 along \( \gamma \)-fiber strengthen along VGR direction by further increase in thickness reduction near thinner side. Accordingly, unprecedented gradual changes in mechanical properties with respect to these changes in microstructure and texture, were obtained. Finally, the correlation between in-plane anisotropic mechanical properties [Young’s modulus (E), yield stress (YS), ultimate tensile stress (UTS) and total elongation] of the studied tailor rolled blank with microstructure and deformation texture was interpreted.