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US 6,645,306 B2Granted
Hydrogen peroxide pickling scheme for stainless steel grades
AssigneeAK Steel Corporation
InventorsVijay N. Madi, Jerald W. Leeker, Clayton A. Van Scoy
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Abstract
The present invention relates to a process for pickling hot rolled, hot rolled & annealed, and cold rolled & annealed stainless steel strip in a continuous fashion. The process comprises a series of pre-pickling tanks and pickling tanks, and optionally includes a scrubber-brush tank, a de-smutting tank, a filtration unit and a heat exchanger.
Claims23
A process for pickling stainless steel strip in a continuous fashion comprising the steps of:
- a. heating a pre-pickling tank, said pre-pickling tank containing an aqueous pre-pickling solution consisting of sulfuric acid and hydrofluoric acid and immersing said strip in said pre-pickling tank;
- b. immersing said strip in a pickling tank after step a, said pickling tank containing an aqueous pickling solution consisting of sulfuric acid, hydrofluoric acid and stabilized hydrogen peroxide;
- and
- c. removing heat from the pickling solution of step b.
1 more element
A process for pickling hot rolled and annealed stainless steel strip in a continuous fashion comprising the steps of:
- a. heating a pre-pickling tank, said pre-pickling tank containing an aqueous solution consisting of sulfuric acid and hydrofluoric acid, and immersing said strip in said pre-pickling tank;
- and
- b. immersing said strip in a pickling tank, after step a, said pickling tank containing an aqueous solution consisting of sulfuric acid, hydrofluoric acid and from about 5 g/l to less than 10 g/l of hydrogen peroxide.
- c. removing heat from the pickling solution of step b.
1 more element
Dependencies are inferred from the claim text.