Surface-treated zinc-coated steel sheet and method for producing same

Abstract

Provided is a surface-treated zinc-coated steel sheet which can exhibit excellent resistance to darkening even after being subjected to a severe ironing process such as a continuous high-speed press molding process and has excellent oil repellency. A surface-treated zinc-coated steel sheet provided with a zinc-coated steel sheet and a surface-treated coating film that is formed on the surface of the zinc-coated steel sheet and contains fluororesin particles, wherein a molten fluororesin region, which is formed as the result of the melting of the fluororesin particles, exists on the surface-treated coating film at an area ratio of 40% or more relative to the whole area of the surface-treated coating film, and the number density of unmolten fluororesin particles in the molten fluororesin region is 50 particles/10 [mu]m2 or less.

Description

technical field [0001] The present invention relates to a surface-treated galvanized steel sheet, and in particular to a surface-treated galvanized steel sheet that has both excellent black spot resistance and oil repellency and can be applied to motor housings and the like without coating. Moreover, this invention also relates to the manufacturing method of the said surface-treated galvanized steel sheet. Background technique [0002] A surface-treated galvanized steel sheet (hereinafter, also simply referred to as "steel sheet") in which the surface of a galvanized steel sheet is surface-treated for the purpose of improving corrosion resistance or the like is used in various fields. For example, in recent years, chromate-free surface-treated galvanized steel sheets provided with a surface-treated film not containing hexavalent chromium have been widely used in home appliances, components of OA equipment, electrical components of automobiles, and the like. [0003] When us...

AI Technical Summary

Problems solved by technology

When the lubricating oil in the bearing part is insufficient due to the leakage of lubricating oil, it will cause the noise and vibration of the motor, and in the worst case, it will cause the motor to fail

[0010] Compared with organic-based coatings, surface-treated coatings mainly composed of inorganic components as described in Patent Documents 1 and 2 have the property that lubricating oil spreads easily on the surface of steel sheets, and they have problems when applied to motor housings.

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