To provide a hot dip galvanized steel sheet excellent in sharpness after painting, as regards the hot dip galvanized steel sheet which is used, for example, by painting it after press-forming it, and the manufacturing method of the same.
The galvanized surface after skin pass rolling is made to satisfy conditions described hereunder by performing the hot dip galvanizing. Wca≤0.6 μm, M≤60%, ppi≥200, d≥1 μm. Where, Wca is the height (μm) of the filtered center-line waviness when the cut-off value of a surface filtered waviness curve is taken as 0.8 mm, M is the area ratio (%) in a part to which skin pass rolling is not applied, and here, M is a value which is determined by the following formula when S0 is the area of the observation visual-field and S1 is the area of a part of the field to which the skin pass rolling is applied, M={(S0-S1)/S0}×100, ppi is the number of the peaks of projecting parts having height of ≥ 5 μm from the center line of a roughness curve per 25.4 mm in length in the direction of the average line of the roughness curve when the cut-off value of the roughness curve is taken as 0.8 mm, and d is the average depth (μm) of dull marks.
JP2003306754A | 2003-10-31 | |||
JP2004035907A | 2004-02-05 | |||
JP2003080302A | 2003-03-18 | |||
JP2006061953A | 2006-03-09 |
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