Surface-treated steel plates and their manufacturing methods

Abstract

The objective is to provide a surface-treated steel sheet and a method for manufacturing the same, which exhibits excellent film corrosion resistance and coating corrosion resistance, even when manufactured without the use of hexavalent chromium, and also possesses a good appearance. To address the aforementioned issues, the surface-treated steel sheet of the present invention comprises: a base steel sheet, and a chromium-containing layer formed on at least one surface of the base steel sheet, characterized in that: the aforementioned chromium-containing layer is composed of a metallic chromium layer and a chromium oxide layer formed on the surface of the metallic chromium layer, the single-sided adhesion amount of the aforementioned chromium oxide layer is 1.0~100.0 mg / m² (in chromium conversion), and it has a thick film portion with a specific area of ​​island-shaped protrusions.

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