Method for continuous pickling of steel materials on a treatment line
AssigneeUgine S.A.
InventorsPaul Didier, Dominique Henriet
Life of this patent
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Abstract
A method for pickling steel materials, in particular continuously on a treatment line, comprising a shot-blasting operation, a preparation operation, a pickling operation and a passivation operation, in which line the preparation operation is carried out by bringing the materials into contact with at least one 2 to 10N sulphuric acid solution, and in which line the pickling operation is carried out by bringing the materials into contact with at least one solution containing 1 to 10% by weight of hydrofluoric acid and Fe.sup.2+ and Fe.sup.3+ ions. No figure.
Claims16
Method for pickling steel materials consisting essentially of a shot-blasting operation, a preparation operation and then at least one pickling operation and at least one passivation operation, characterized in that the preparation operation is carried out by bringing the materials into contact with at least one 2 to 10N sulphuric acid solution at a temperature higher than 50.degree. C., the metals content being below the saturation level, and in that the pickling operation is carried out by bringing the materials into contact with at least one solution which has a temperature of between 40.degree. and 95.degree. C. and consists essentially of 1 to 10% by weight of hydrofluoric acid, and Fe.sup.2+ and Fe.sup.3+ such that the Fe.sup.3+ ion concentration is between 1 and 190 g/l and that the redox potential is between -200 and +800 mV, this potential being measured using a platinum electrode with respect to an Ag/AgCl electrode.
Dependencies are inferred from the claim text.