| Title |
Grain Refinement by Severe Deformation using ECAP in 0.15%C Steel |
| Authors |
신동혁(Dong Hyuk Shin),오개희(Kae Hee Oh),김우진(Woo Jin Kim),주웅용(Wung Yong Choo) |
| Abstract |
Experiments were conducted on 0.15%C steel with an initial grain size of ∼40 ㎛ for obtaining an ultra-fine grain structure and enhanced tensile properties. ECA pressing was successfully conducted at 200℃ by designing the channel angle and the arc of curvature at the outer point of intersection of two channels properly. The Vickers hardness increased significantly by a factor of 1.6 even with a single pass. Subsequently, the hardness increased slightly after second pass. The microstructure was refined after a single pass and consisted of parallel bands of elongated subgrains. These subgrains were developed to fine grains by repeating the pass. At least for 0.15%C steel, it was possible to achieve equiaxed fine grains of ∼0.5 ㎛ by applying 2 passes such that the sample was rotated by 180℃ in the second pass. |