The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 25, 1989
Filed:
May. 03, 1988
Applicant:
Inventor:
Gerald Maresch, Modling, AT;
Assignee:
Maschinenfabrik Andritz Actiengesellschaft, Graz, AT;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C25F / ;
U.S. Cl.
CPC ...
2041 / ;
Abstract
In a process for the electrolytic pickling of chromium-containing stainless steel, pickling proceeds initially in an aqueous Na.sub.2 SO.sub.4 solution and subsequently in acid, preferably mixed acid. The CrO.sub.4.sup.2- formed is converted by the addition of reducing agent and acid as a function of the pH value and the redox potential to Cr.sub.2 (SO.sub.3).sub.3 or Cr.sub.2 (SO.sub.4).sub.3. H.sub.2 SO.sub.4 serves as the acid and a substance is used as a reducing agent selected from the group Na.sub.x H.sub.y S.sub.z O.sub.v, wherein x=0 to 2, y=0 to 2, y=1 to 6 and v=2 to 6. The pH value is adjusted to less than three by the addition of acid.