Method of making austenitic stainless steel sheet
US6149744A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1998 |
| Grant date | Nov 21, 2000 |
| Priority date | — |
| Expiry date | Oct 23, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC25F1/06
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
Method of making a hot-rolled steel sheet having superior surface appearance, free of surface patterns and uneven glossiness from an austenitic stainless steel slab containing about 0.03 percent by weight or more of Cu, about 0.03 percent by weight or more of V, and about 0.01 percent by weight or more of Mo under any of the following conditions: (A) pickling in a nitric-hydrofluoric acid solution containing about 20 to 100 g/l of nitric acid and about 100 to 300 g/l of hydrofluoric acid; (B) controlling nitric-hydrofluoric acid content in response to the iron ion content in the solution; (C) a preliminary pickling step prior to finishing pickling; (D) grinding about 2 .mu.m or more of the surface after preliminary pickling and prior to finishing pickling; (E) causing counterflow with a relative flow rate of 0.5 to 5.0 m/sec on the sheet surface during finishing pickling; (F) adding sulfuric acid or sulfurous acid as a hydrogen ion source to the nitric-hydrofluoric acid solution; and (G) electrolysing during finishing pickling such that the ratio of the cathodic electrolysis time to the anodic electrolysis time is about 3 or more.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.