| 摘要 |
PROBLEM TO BE SOLVED: To secure a uniform surface skin on which spangle pattern on a galvanized surface is fully eliminated in the manufacture of a galvanized steel sheet. SOLUTION: A skinpass rolling is executed after galvanizing by using dull- rolls having the following surface roughness composed of craters 11 and rims 12 formed with an electronic beam dull working. That is, the opening diameter (D) of the crater: 30-180μm, the distance (L) between the adjacent craters: 1.5D-3D (wherein, L<=180μm) and the height (R) of the rim: >=2μm. The above skinpass rolling is not necessary to excess rolling load. The general rolling reduction condition (the extending ratio of the steel sheet: about 0.5-1%) in the skinpass rolling is applied and the full elimination of the spangle pattern can be achieved with one time of the skinpass.
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