STEEL SHEET HAVING GOOD PAINTING IMAGE CLEARITY AND ITS MANUFACTURING METHOD

摘要

PURPOSE:To improve the seizing resistance and painting image clearity of a steel sheet by bringing shapes of a steel sheet surface to have specific wavelength component strength. CONSTITUTION:Uniquely shaped ruggedness are formed on a steel sheet surface by use of a skin pass rolling roll dull finished by high density energy beams such as laser beams. For the sheet having such a surface condition, annular recessed parts 2a act a role as a lubricating oil reservoir and a cut powder catcher in forming operation and produce die seizing preventing effect. Further, many flat parts exist on the surface to restrain irregular reflection and to make image clearity good. A wavelength component strength of the wavelength lambdacontained in the range of 585mum=lambda2,730mum when shapes of the steel sheet is frequency analized is brought to be =0.2. As the result, the dull finished steel sheet having an image clearity similar to that of a bright finished steel sheet is obtained.