The Isolated Austenite Forming during High-Temperature Cooling and Its Influence on Pitting Corrosion Resistance in S32750 Duplex Stainless Steel
The formation mode of isolated austenite (IA) formed during high-temperature cooling and its effect on pitting corrosion resistance of S32750 DSS were investigated. As the structure formed during the high-temperature cooling process after hot rolling in S32750 duplex stainless steel (DSS), the preci...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-08-01
|
| Series: | Metals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-4701/12/8/1316 |
| _version_ | 1797408895716556800 |
|---|---|
| author | Xiaohan Wu Zhigang Song Jianguo He Zhiyi Bao Han Feng Wenjie Zheng Yuliang Zhu |
| author_facet | Xiaohan Wu Zhigang Song Jianguo He Zhiyi Bao Han Feng Wenjie Zheng Yuliang Zhu |
| author_sort | Xiaohan Wu |
| collection | DOAJ |
| description | The formation mode of isolated austenite (IA) formed during high-temperature cooling and its effect on pitting corrosion resistance of S32750 DSS were investigated. As the structure formed during the high-temperature cooling process after hot rolling in S32750 duplex stainless steel (DSS), the precipitation of isolated austenite (IA) can be considered as the combined production of temperature and cooling rates. IA generated at the ferrite (α) grain boundaries or internal α and performed the K-S crystallographic relation with the α N element enriched in IA. The redistribution of elements not only increased the concentration gradient between α/IA, but also reduced the pitting resistance equivalent number (PREN) of original austenite (γ). Scanning Kelvin probe (SKP) and Gaussian fitting proved that with prolonged corrosion time, the potential difference enlarged and local corrosion aggravated. Measured by the weight loss method, pitting resistance decreased to one-third of the solid solution state due to the existence of IA; following, the quantities, sizes, and depth of corrosion pits increased significantly. In addition to α/γ boundaries and α/α boundaries, corrosion pits preferred to initiate around IA. The IA that appeared at α grain boundaries deteriorated the pitting corrosion resistance severely. Furthermore, original austenite with decreased PREN tended to be corroded. In general, the order of pitting occurrence is displayed as follows: α-γ-IA. |
| first_indexed | 2024-03-09T04:05:12Z |
| format | Article |
| id | doaj.art-1570ae731d624eff9de93a39ff60e0a4 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-09T04:05:12Z |
| publishDate | 2022-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-1570ae731d624eff9de93a39ff60e0a42023-12-03T14:06:57ZengMDPI AGMetals2075-47012022-08-01128131610.3390/met12081316The Isolated Austenite Forming during High-Temperature Cooling and Its Influence on Pitting Corrosion Resistance in S32750 Duplex Stainless SteelXiaohan Wu0Zhigang Song1Jianguo He2Zhiyi Bao3Han Feng4Wenjie Zheng5Yuliang Zhu6School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083, ChinaCentral Iron & Steel Research Institute, Beijing 100081, ChinaCentral Iron & Steel Research Institute, Beijing 100081, ChinaCentral Iron & Steel Research Institute, Beijing 100081, ChinaCentral Iron & Steel Research Institute, Beijing 100081, ChinaCentral Iron & Steel Research Institute, Beijing 100081, ChinaCentral Iron & Steel Research Institute, Beijing 100081, ChinaThe formation mode of isolated austenite (IA) formed during high-temperature cooling and its effect on pitting corrosion resistance of S32750 DSS were investigated. As the structure formed during the high-temperature cooling process after hot rolling in S32750 duplex stainless steel (DSS), the precipitation of isolated austenite (IA) can be considered as the combined production of temperature and cooling rates. IA generated at the ferrite (α) grain boundaries or internal α and performed the K-S crystallographic relation with the α N element enriched in IA. The redistribution of elements not only increased the concentration gradient between α/IA, but also reduced the pitting resistance equivalent number (PREN) of original austenite (γ). Scanning Kelvin probe (SKP) and Gaussian fitting proved that with prolonged corrosion time, the potential difference enlarged and local corrosion aggravated. Measured by the weight loss method, pitting resistance decreased to one-third of the solid solution state due to the existence of IA; following, the quantities, sizes, and depth of corrosion pits increased significantly. In addition to α/γ boundaries and α/α boundaries, corrosion pits preferred to initiate around IA. The IA that appeared at α grain boundaries deteriorated the pitting corrosion resistance severely. Furthermore, original austenite with decreased PREN tended to be corroded. In general, the order of pitting occurrence is displayed as follows: α-γ-IA.https://www.mdpi.com/2075-4701/12/8/1316pitting corrosionelemental redistributionduplex stainless steelscanning Kelvin probespecific interface |
| spellingShingle | Xiaohan Wu Zhigang Song Jianguo He Zhiyi Bao Han Feng Wenjie Zheng Yuliang Zhu The Isolated Austenite Forming during High-Temperature Cooling and Its Influence on Pitting Corrosion Resistance in S32750 Duplex Stainless Steel Metals pitting corrosion elemental redistribution duplex stainless steel scanning Kelvin probe specific interface |
| title | The Isolated Austenite Forming during High-Temperature Cooling and Its Influence on Pitting Corrosion Resistance in S32750 Duplex Stainless Steel |
| title_full | The Isolated Austenite Forming during High-Temperature Cooling and Its Influence on Pitting Corrosion Resistance in S32750 Duplex Stainless Steel |
| title_fullStr | The Isolated Austenite Forming during High-Temperature Cooling and Its Influence on Pitting Corrosion Resistance in S32750 Duplex Stainless Steel |
| title_full_unstemmed | The Isolated Austenite Forming during High-Temperature Cooling and Its Influence on Pitting Corrosion Resistance in S32750 Duplex Stainless Steel |
| title_short | The Isolated Austenite Forming during High-Temperature Cooling and Its Influence on Pitting Corrosion Resistance in S32750 Duplex Stainless Steel |
| title_sort | isolated austenite forming during high temperature cooling and its influence on pitting corrosion resistance in s32750 duplex stainless steel |
| topic | pitting corrosion elemental redistribution duplex stainless steel scanning Kelvin probe specific interface |
| url | https://www.mdpi.com/2075-4701/12/8/1316 |
| work_keys_str_mv | AT xiaohanwu theisolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel AT zhigangsong theisolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel AT jianguohe theisolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel AT zhiyibao theisolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel AT hanfeng theisolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel AT wenjiezheng theisolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel AT yuliangzhu theisolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel AT xiaohanwu isolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel AT zhigangsong isolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel AT jianguohe isolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel AT zhiyibao isolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel AT hanfeng isolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel AT wenjiezheng isolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel AT yuliangzhu isolatedausteniteformingduringhightemperaturecoolinganditsinfluenceonpittingcorrosionresistanceins32750duplexstainlesssteel |