Pickling Process of Alloy 625 Cold-rolled Sheets

The orthogonal pickling tests for 2 mm-thick 625 alloy cold-rolled sheets were conducted by using the alkali washingmixed acid pickling process. The results showed that the best pickling process for 625 alloy cold-rolled sheets is as follows:Firstly, the sheets should be alkali washed in 80% Na OH + 20% NaNO₃ (w) for 60~120 s at 500~550℃ and then pickled 20% HNO₃+ 4% HF for 30~60 s at 45~50℃. After pickling and finishing, the sheet surfaces of 2 B level could be ganed and performance indexes are equivalent to those of the imported sheets.