Texture evolution of ferrite steel during anisotropic tensile deformation studied by neutron diffraction

中性子回折を用いた異向引張変形中のフェライト鋼の集合組織変化

徐 平光   ; 鈴木 徹也*; 山中 啓輔*; 秋田 貢一

Xu, P. G.; Suzuki, Tetsuya*; Yamanaka, Keisuke*; Akita, Koichi

The high strength pipeline steels with resistance to strain-aged hardening are being required in the permafrost ground or seismic region because the local buckling deformation (a phenomenon related to the anisotropic plastic deformation) may occur during the production or the service of pipeline and plate steels. The 2% pre-strain deformation led to a certain residual strain occurring in the steel and such strain did not disappear after 423K ageing treatment, suggesting that the strain-aged anisotropy should be related to the pre-strain induced crystallographic characteristics. Here, the change in bulk texture during the anisotropic tensile deformation was investigated with MUSASI-L neutron diffractometer. The texture of the sample along the pre-strained direction became stronger at {110}001 and {001}110 orientation components at a small strain and then the ferrite grains rotated to {110}001 orientation component. On the other hand, the texture of the sample perpendicular to the pre-strained direction showed only little rotation to {110}001 texture component until the 2.0% tensile strain, and then the ferrite grains rapidly rotated to {110}001 orientation component.