| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel plate to be cut with a laser, which stably shows excellent laser sectility and enables the unmanned driving of a laser cutting machine in the nighttime, and to provide a manufacturing method therefor. SOLUTION: The slab of the steel plate includes, by mass%, 0.03-0.50% Cu, 0.02-0.50% Ni while satisfying the expression of mass ratio Ni/Cu≥0.5, and further 0.05% or more Si. The method for manufacturing the steel plate comprises the steps of: heating the above slab so that the surface temperature can reach or exceed a melting point of the Cu-Ni alloy having the same composition as the Ni/Cu mass ratio in the above steel, at least for a period of time when the slab is heated; cooling the heated slab until the surface temperature drops to the melting point of the Cu-Ni alloy or lower; then removing the scale by spouting water onto the slab; and hot-rolling the descaled slab into a predetermined plate thickness. The manufactured steel plate acquires a scale/metal mixture layer with a thickness of 5 to 30μm, which consists of the surface scale layer and a mixture layer that exists in the vicinity of a boundary between the scale layer and a steel base metal and contains metallic fine particles formed of the Fe-Cu-Ni-based alloy dispersed in the scale. COPYRIGHT: (C)2006,JPO&NCIPI
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