Process for the acid pickling of stainless steel products
US5690748A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 10, 1993 |
| Grant date | Nov 25, 1997 |
| Priority date | — |
| Expiry date | Nov 10, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23G1/08
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The invention relates to a process for pickling stainless steel products, in which the pickling bath used has as its initial composition, HF.gtoreq.10 g/l, dissolved ferric iron (Fe.sup.3+).gtoreq.15 g/l, and water=balance. During the pickling operation(s), the redox potential of the bath is monitored and maintained between +100 mV and +350 mV by oxidation of the bath, if necessary, by at least one or several addition(s) of oxidant to the bath. The process of the invention applies particularly to the industrial pickling of stainless steel sheets and strips, in which it is possible to avoid the use of nitric acid and the resulting pollution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.