ELECTROGALVANIZED STEEL SHEET AND SURFACE TREATED ELECTROGALVANIZED STEEL SHEET EXCELLENT IN UNIFORMITY OF SURFACE APPEARANCE

摘要

PROBLEM TO BE SOLVED: To produce an electrogalvanized steel sheet excellent in the uniformity of the surface appearance regardless of the microscopic ununiformity of the surface of the base original sheet, in the crystal planes in an optional region of the plated surface, by specifying the orienation properties of each Miller index plane of zinc crystals. ;SOLUTION: In the optional region of the plated surface of an electrogalvanized steel sheet, the orientation property value Z defined by the formula as for the crystal planes obtd. by X-ray diffraction measurement using a Cu-Kα line or the like is regulated to 1.0 to 3.0, where, in the formula, (hk.L): 7 kinds of crystal planes of (00.2), (00.4), (10.3), (10.2), (10.1), (10.0) and (11.0), I(hk.L): the diffraction intensity of the 7 kinds of crystal planes by X-ray diffraction for the electrogalvanizing layer, and I₀(hk.L): the standard x-ray diffraction relative intensity in the above 7 kinds of crystal planes of zinc powder described in ASTM(american society of testing material). This electrogalvanizing preferably is a single layer structure. A covering layer essentially consisting of chromate coating film and a film of organic matter is formed on the surface of the above plating layer as necessary.;COPYRIGHT: (C)1997,JPO