Process for surface treatment of stainless steel sheet

A process for surface treatment of a stainless steel sheet comprising dipping a stainless steel sheet having a bright annealing film or a passive film in a treatment solution and carrying out cathodic treatment under conditions of 1 to 600 A-sec/dm.sup.2 integrated current density and 0.degree. to 90.degree. C. solution temperature, said treatment solution containing 0.1 to 70.0% by weight of phosphoric acid and 0.1 to 10.0% by weight of a molybdate.

A process for surface treatment of a stainless steel sheet by dipping such a sheet having a bright annealing film or a passive film in a treatment solution and carrying out cathodic treatment thereof comprising the steps of performing said cathodic treatment in two steps, the first step comprising dipping a stainless steel sheet having a bright annealing film or a passive film in a treatment solution containing 0.1 to 50.0% by weight of phosphoric acid, 0.1 to 10.0% by weight of chromic acid, and 0.1 to 2.0% by weight of a member selected from the group consisting of magnesium oxide, sodium silicate and mixtures thereof and carrying out cathodic treatment under the conditions of 1 to 600 A-sec/dm.sup.2 integrated current density and 0.degree. to 90.degree. C. solution temperature, and a second step comprising dipping the stainless steel sheet treated in the first step in a treatment solution containing 0.1 to 70% by weight of phosphoric acid and 0.1 to 10.0% by weight of a molybdate and carrying out cathodic treatment under the conditions of 1 to 600 A-sec/dm.sup.2 integrated current density and 10.degree. to 90.degree. C. solution temperature.

A process for surface treatment of a stainless steel sheet by dipping such a sheet having a bright annealing film or a passive film in a treatment solution and carrying out cathodic treatment thereof comprising the steps of performing said cathodic treatment in two steps, the first step comprising dipping a stainless steel sheet having a bright annealing film or a passive film in a treatment solution containing 0.1 to 70% by weight of phosphoric acid and 0.1 to 10.0% by weight of a molybdate and carrying out cathodic treatment under the conditions of 1 to 600 A-sec/dm.sup.2 integrated current density and 10.degree. to 90.degree. C. solution temperature, and a second step comprising dipping the stainless steel sheet treated in the first step in a treatment solution containing 0.1 to 50.0% by weight of phosphoric acid, 0.1 to 10.0% by weight of chromic acid, and 0.1 to 2.0% by weight of a member selected from the group consisting of magnesium oxide, sodium silicate and mixtures thereof and carrying out cathodic treatment under the conditions of 1 to 600 A-sec/dm.sup.2 integrated current density and 0.degree.to 90.degree. C. solution temperature.