EBSD analysis and mechanical properties of low-carbon steel during drawing with shear deformation

Abstract

In the current study, the effect of shear deformation combined with conventional drawing processes on the evolution of the microstructure, texture and mechanical properties of low-carbon steel was investigated using electron backscatter diffraction, Vickers microhardness and tensile test. For that, two samples were drawn with a shear die to 8 (ShD8–23 sample) and 23 % (ShD23–23 sample) of diameter reduction and followed by conventional drawing for a diameter reduction of 23 %, respectively. The results show that the overall grain size reduction was about 9.2 and 12.8 % and a significant increase in low-angle grain boundary fraction of 77.8 and 85.9 % for ShD8–23 and ShD23–23 samples, respectively. A typical <110>//DD fiber containing A {110}<001>, B {110}<111> and C {110}<110> components was formed in both samples. In contrast to the B and C components, the stored energy in the A component, estimated by the Kernel Average Misorientation (KAM) approach, was found to be low and stable with increasing deformation. The ultimate tensile strength of the ShD8–23 and ShD23–23 samples was improved by 49 and 52 %, respectively. The yield strength was increased by 95 and 108 % for ShD8–23 and ShD23–23 samples, respectively. The mechanical properties improvement was related to the deformation and initial microstructure. The contribution of dislocation strengthening, originated from geometrically necessary dislocations, is found to be dominant for the increase of yield strength rather than grain refinement strengthening.