Modeling the crystallographic texture of of ferritic/martensitic steel during rolling: the level and anisotropy of strength properties

Abstract

This paper presents the results of studies of the level and anisotropy of strength properties in ferritic / martensitic steel during warm rolling based on the data on crystallographic texture. The features of texture formation processes in the initial and UFG samples subjected to flat rolling are analyzed by the method of texture analysis and computer modeling. In particular, the analysis of the orientation distribution function (ODF) made it possible to establish the change in the main preferential orientations (Brass, Goss, Copper, Cube, TC, Y, Z and Rotated Cube) depending on the degree of reduction. It is shown that in flat rolling, a stable rolling texture is formed only after 70 % reduction, at which H {001}<011>, Goss {001}<110>, Cube {100}<001> and TC {255}<511> orientations become the main ones. At high degrees of flat rolling, the sharpness of the above textural maxima increases, which is accompanied by the activation of a smaller number of slip systems, and the misorientations between adjacent grains become predominantly high-angle ones. Within the framework of modeling of crystallographic textures, deformation mechanisms were established, two-dimensional projections of yield contours, Young's module and Lankford coefficients (r-value) were constructed. In particular, the results of computer simulation of the yield contours of steel after tempering the coarse-crystalline and UFG states showed that at low degrees of flat rolling reduction, an increased level of anisotropy of strength properties is associated with the residual crystallographic texture in the workpiece, and an increase in the degree of flat rolling leads to alignment of the strength anisotropy in sheets. It was found that the quantitative ratio of the main textural components of the type H {001}<011>, Goss {001}<110>, Cube {100}<001> and TC {255}<511> during rolling determine the anisotropy of the strength properties of steel.