ORGANIC COATING STEEL SHEET EXCELLENT IN CORROSION RESISTANCE, CORROSION RESISTANCE AFTER ALKALINE DEGREASING AND COATING PROPERTIES

摘要

PROBLEM TO BE SOLVED: To provide a zinc-plated steel sheet which has a chemical conversion coating being safe and nonpolluting in a manufacturing process and further in a process of the use and which is excellent in white rust resistance, the white rust resistance after alkaline degreasing and coating adhesion. ;SOLUTION: This steel sheet has an Si-Al composite oxide coat wherein an Al/(Al+Si) ratio is 0.01-0.8 in a molar ratio and further which contains a silane coupling agent in the ratio of 0.001-10 to the Si, in the coating build-up of 2-5000 mg/m² in terms of the Si and the Al in total, on the surface of a zinc-plated steel sheet and further has an organic resin coat or an organic composite silicate coat in a coat thickness of 0.1-3 μm on the surface of the composite oxide coat. Thereby the organic coating steel sheet excellent in corrosion resistance, the corrosion resistance after alkaline degreasing and coating properties can be obtained.;COPYRIGHT: (C)1998,JPO