Lubricant film coated steel sheet with excellent phosphatability and method for producing same
AssigneeKabushiki Kaisha Kobe Seiko Sho
InventorsMasatoshi Iwai, Hiroaki Nakano
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Abstract
A lubricant film coated steel sheet having excellent phosphatability, in accordance with the present invention, is a lubricant film coated steel sheet produced by forming a coating containing silicic acid or silicate on a steel sheet or a plated steel sheet, wherein the surface roughness of the steel sheet or the plated steel sheet is 0.5 to 1.5 .mu.m as the centerline-average roughness RA and the PPI (cut-off value of 1.25 .mu.m) thereof is 75 to 300; and the content of silicic acid or silicate in the coating is 1 to 200 mg/m.sup.2 as corrected into dried SiO.sub.2 weight or the coating ratio of the coating is 1 to 60%.
Claims16
A lubricant film coated steel sheet having excellent phosphatability, produced by forming a coating containing silicic acid or silicate on a steel sheet or a plated steel sheet, having micro-fine recesses and protrusions on the surface thereof,
- wherein the surface roughness of the steel sheet or the plated steel sheet, prior to coating, is 0.5 to 1.5 .mu.m as the centerline-average roughness RA and the total number of peaks of a size above 1.25 .mu.m per 1-cm length PPI thereof is 75 to 300;
- and
- the content of silicic acid or silicate in the coating is 1 to 200 mg/m.sup.2 as corrected into dried SiO.sub.2 weight or the covered ratio of the coating is 1 to 60%.
Dependencies are inferred from the claim text.