WET ON WET METHOD AND CHROME-FREE ACIDIC SOLUTION FOR THE CORROSION CONTROL TREATMENT OF STEEL SURFACES

A process for anticorrosion treatment of bare metal surfaces comprising steel surfaces, wherein the bare metal surfaces are contacted with an acidic aqueous solution of a fluoro complex of at least one element M selected from the group B, Si, Ti, Zr and Hf, at least one further component which is selected from among: a buffer system for the pH range from 2.5 to 5.5, nitrate ions, copper ions, silver ions, vanadium or vanadate ions, bismuth ions, magnesium ions, zinc ions, manganese ions, cobalt ions, nickel ions, tin ions, aromatic carboxylic acids with at least two groups containing donor atoms, or derivatives of such carboxylic acids, and silica particles with an average particle size of below 1 mum; and contains no more than 1 mg/l of an organic polymer with allylamine or vinylamine monomers; the metal surfaces are then rinsed with water and thereafter are coated with a cathodically depositable electro-dipcoating.