EP 0494431 B1 19961016 - Method for producing chromate-treated plate steel material
Title (en)
Method for producing chromate-treated plate steel material
Title (de)
Verfahren zur Erzeugung von chromatbehandelten Stahlplatten
Title (fr)
Méthode de production de plaque en acier traitée aux chromates
Publication
Application
Priority
JP 40678590 A 19901226
Abstract (en)
[origin: EP0494431A1] According to the present invention, it is possible to produce a chromate-treated plated steel material which achieves an improved appearance thereof, particularly the minimization of a yellow tint peculiar to chromate, and enhanced corrosion resistance simultaneously and at a lower cost, which has been difficult with a prior art. There is provided a method for producing a chromate-treated plated steel material, comprising the steps of applying on at least one surface of a zinc- or zinc alloy-plated steel material a solution containing 1 to 15% by weight of chromic acid and/or reduced products of chromic acid having trivalent chromium and hexavalent chromium in the proportion of 1/2 to 1/1 by weight as the total amount of metal chromium, colloidal silica, calculated as SiO2, in the proportion of 1/2 to 6/1 of the total weight of chromium, and further 0.1 to 10% by weight of at least one selected from the group consisting of carboxylic acids and/or derivatives thereof, which are stable in said solution, heating and baking said chromate-treated steel material at a temperature ranging from 150 DEG C to 300 DEG C to form a chromate film having hexavalent chromium on the surface thereof in the proportion of 20% or less of the total weight of chromium and having a deposit of 10 to 150 mg/m<2> calculated as chromium.
IPC 1-7
IPC 8 full level
C23C 22/30 (2006.01); C23C 22/27 (2006.01); C23C 22/74 (2006.01)
CPC (source: EP KR)
C23C 22/05 (2013.01 - KR); C23C 22/74 (2013.01 - EP)
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
EP 0494431 A1 19920715; EP 0494431 B1 19961016; DE 69122735 D1 19961121; DE 69122735 T2 19970320; JP H04247882 A 19920903; JP H0733583 B2 19950412; KR 920012519 A 19920727; KR 940004100 B1 19940513
DOCDB simple family (application)
EP 91122028 A 19911220; DE 69122735 T 19911220; JP 40678590 A 19901226; KR 910024701 A 19911226