Influence of Tensile Strain on Young’s Modulus in High-strength Cold-rolled Steel Sheets

The change of Young’s modulus accompanying tensile deformation was investigated for an anisotropic high-strength cold-rolled steel sheet with a high Young’s modulus value in the transverse direction and an isotropic steel sheet with no prominent development of texture. The characteristic phenomenon was the decrease in Young’s modulus in the transverse direction by tensile deformation in the transverse direction in the anisotropic steel sheet. The drop of Young’s modulus in the transverse direction was attributable to a decrease in the ODF intensity around {112} . Young’s modulus in the diagonal direction also decreased somewhat as a result of tensile deformation in the rolling and diagonal directions in the anisotropic steel sheet. This change was caused mainly by an increase in ODF intensity around {001} . Young’s modulus in the rolling direction displayed little change as a result of tensile deformation because the texture on the α-fiber and γ-fiber, which were mainly developed in cold-rolled steel sheets, showed an almost constant Young’s modulus in the rolling direction. In the isotropic steel sheet, Young’s modulus showed little change in any direction as a result of tensile deformation. Young’s modulus calculated by the Voigt model had relatively good correspondence with the measured results. Concerning simulation of crystal rotation, the Taylor model indicated that the crystals around the α-fiber from {112} to {111} rotated to the vicinity by tensile deformation in the transverse direction. The remarkable change of Young’s modulus was explained by the crystal rotation simulated by the Taylor model.