Pickling behavior of 2205 duplex stainless steel hot-rolled strips in mixed solutions of HNO3-HF
Abstract
The pickling behaviour of 2205 DSS hot-rolled strips after annealing and sand blasting was studied in the mixed solutions of HNO3-HF using weight loss rate, surface analysis, corrosion potential, and electrochemical impedance spectroscopy measurements. The pickling rate decreased as the concentration of HNO3 increased in the mixed solutions of x HNO3 + 25 g l-1 HF (x = 40 ∼ 200 g l-1) at 50 °C due to passivation. The passivating effect of HNO3 became weak as its concentration was less than 80 g l-1. The pickling rate increased noticeably when the concentration of HF in the mixed solutions of 120 g l-1 HNO3 + y HF (y = 5 ∼ 80 g l-1) at 50 °C was increased. The dissolution of the metal under the oxide scale may have changed from the passive state to the active state as the HF concentration was higher than 25 g l-1. The pickling dissolution accelerated noticeably as the temperature rose from 40 to 60 °C. With the optimised pickling process, 2205 DSS hot-rolled strips can be pickled industrially with good efficiency and surface topography.
- Publication:
-
Materials Research Express
- Pub Date:
- April 2020
- DOI:
- 10.1088/2053-1591/ab81c0
- arXiv:
- arXiv:2003.08174
- Bibcode:
- 2020MRE.....7d6502P
- Keywords:
-
- 2205 duplex stainless steel;
- HNO3-HF;
- corrosion potential;
- pickling;
- electrochemical impedance spectroscopy;
- Physics - Applied Physics
- E-Print:
- 12 pages, 14 figures,3 tables