Process and plant for pickling materials made of steel, in particular stainless steel
AssigneeAndritz-Patentverwaltungs-Gesellschaft m.b.H.
InventorsJovan Starcevic, Erich Mahr
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Abstract
The invention concerns a process for pickling material strips made of steel, in particular stainless steel, where the strip passes through at last one pickling bath with at least one pickling acid. It is above all characterized by the fact that the acid concentration and/or the acid composition is controlled as a function of the material quality, of the pre-treatment and of the operating parameters of the pickling plant. Furthermore, the invention concerns a plant for carrying out the process, where at least two circulation tanks having different acid concentrations and/or acid compositions are provided.
Claims22
Process for pickling material strips made of stainless steel, the stainless steel having a material quality and being subjected to pre-treatment prior to pickling, the process comprising the steps of:
- selecting a mixed acid composed of a combination of hydrofluoric acid and nitric acid, the combination affecting a composition and a concentration of the mixed acid;
- placing a quantity of the mixed acid in at least one pickling path to form a pickling bath;
- and
- passing the strip through the pickling path,
- wherein the composition and concentration of the mixed acid in the pickling bath is selected and automatically, continuously controlled as a function of the material quality, operating parameters of the pickling bath, and the operating parameters of the pre-treatment of the strip.
Process for pickling material strips made of stainless steel, the stainless steel having a material quality and being subjected to pre-treatment prior to pickling, the process comprising the steps of:
- selecting a mixed acid composed of a combination of hydrofluoric acid and nitric acid, the combination affecting a composition and a concentration of the mixed acid, the composition being selected and automatically, continuously controlled as a function of the material quality, operating parameters of the pickling bath, and the operating parameters of the pretreatment of the strip;
- placing a quantity of the mixed acid in at least one pickling path to form a pickling bath;
- and
- passing the strip through the pickling path.
Process for pickling material strips made of stainless steel, the stainless steel having a material quality and being subjected to pre-treatment prior to pickling, the process comprising the steps of:
- selecting a mixed acid composed of a combination of hydrofluoric acid and nitric acid, the combination affecting a composition and a concentration of the mix acid, the concentration being selected and automatically, continuously controlled as a function of the material quality, operating parameters of the pickling bath, and the operating parameters of the pretreatment of the strip;
- placing a quantity of the mixed acid in at least one pickling path to form a pickling bath;
- and
- passing the strip through the pickling path.
A plant for pickling material strips made of stainless steel, comprising:
- pickling bath means for bathing the steel strips in a quantity of pickling acid contained therein, the pickling acid having a combination of feed acids, the combination defining a composition and a concentration of the pickling acid;
- circulation tank means for storing the feed acid, selectively feeding the feed acid to the pickling bath means, and receiving a waste acid from the pickling bath means, the circulation tank means comprising a plurality of circulation tanks in fluid communication with the pickling bath means, each of the circulation tanks containing a feed acid having a composition and concentration that is different from the composition and concentration of the feed acid contained in each other circulation tank, one of the circulation tanks storing a feed acid composed of hydrofluoric acid and another of the circulation tanks storing a feed acid composed of nitric acid;
- and
- control means disposed intermediate the circulation tank means and the pickling bath means for controlling the composition and concentration of the pickling acid by selectively feeding feed acid from one of the circulation tanks or another of the circulation tanks.
Dependencies are inferred from the claim text.