Strain Distribution Analysis Using Precise Markers in Cold-Rolled Ultra-Low Carbon Steel

In this study, the strain distribution in grains with a preferred orientation in a cold-rolled steel plate was investigated. This was done by measuring the amount of strain in a region of the material using nanoscale fine markers applied by a focused ion beam (FIB). We obtained the crystal orientations and strain distributions in the same region using scanning electron microscopy-electron backscatter diffraction and the markers made by the FIB during rolling to a 60% to 70% thickness reduction. The method revealed the strain distributions in the grains with the major preferred orientations (cube:{100}<001>; α-fiber:{100}<011>, {211}<011>; γ-fiber:{111}<011>, {111}<211>). The average strains that accumulated in the grains with different major preferred orientations during cold-rolling were almost the same at thickness reduction in the range of 60%–70%. However, the strain distribution width of the γ-fiber grains was approximately twice that of grains with other orientations. These results suggest that the deformation inhomogeneity during rolling is more pronounced for γ-fiber-oriented grains than for grains with other preferred orientations.