| 摘要 |
PROBLEM TO BE SOLVED: To provide a thick steel plate excellent in scale adhesion and method for manufacturing the same.SOLUTION: A steel raw material containing C:0.03-0.20%, Si:0.05-0.5%, Mn:0.5-2.0%, P:0.030% or less, S:0.02% or less, Al:0.10% or less by mass % and having composition consisting of the remainder Fe and inevitable impurities is heated at temperature of 950-1200°C, and after that, performed hot rolling to be made into a thick steel plate, descaled by high pressure water whose collision pressure becomes 1.5-4.0 Mpa at temperature of 650-900°C by surface temperature after the hot rolling, and accelerated cooling is started within 10s. The accelerated cooling to become 50°C/s or more by average cooling speed between the start of cooling and 650°C by surface temperature is performed to cooling stop temperature at which steel plate surface temperature after recuperation becomes 650°C or lower. Thus, the steel raw material becomes to have average scale thickness: less than 10μm, porosity: 5% or less, and interfacial peeling area ratio between a scale and ground iron: 15% or less. |
