Microstructures and Corrosion/Localised Corrosion of Stainless Steels, Incoloy and Their Weldments in Nitrite-Containing Chloride Environments
Prompted by the unexpected observation of the pitting of the weldments of a highly corrosion- and pitting-resistant duplex stainless steel, SAF2507, in chloride solutions with nitride addition, the pitting and corrosion resistance of SAF2507 and its weldments were investigated in chloride solutions...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-03-01
|
| Series: | Materials |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1996-1944/17/6/1336 |
| _version_ | 1797240180304773120 |
|---|---|
| author | R. K. Singh Raman W. H. Siew |
| author_facet | R. K. Singh Raman W. H. Siew |
| author_sort | R. K. Singh Raman |
| collection | DOAJ |
| description | Prompted by the unexpected observation of the pitting of the weldments of a highly corrosion- and pitting-resistant duplex stainless steel, SAF2507, in chloride solutions with nitride addition, the pitting and corrosion resistance of SAF2507 and its weldments were investigated in chloride solutions with and without different levels of nitrite. The Incoloy 825 and 316L austenitic stainless steels were included for the purpose of developing a comparative appreciation. The microstructures of the weldments were characterised, and 316L showed a profound influence of nitrite addition in inhibiting pitting, while ‘meta-stable’ pitting transients that were clearly visible in the chloride solution without nitrite were absent when nitrite was added. Both the parent metal and the weldment of SAF2507 had similar pitting potential (E<sub>p</sub>) in 0.1 M NaCl without nitrite, which was the highest E<sub>p</sub> among the three alloys tested. Additions of nitrite at low concentrations had an inhibitive effect on pitting, whereas higher nitrite contents had a deleterious effect on pitting resistance. On the other hand, Incoloy 825 showed a trend of E<sub>p</sub> ennoblement with an increasing nitrite content of 0.1 M NaCl, and the weldment underwent greater ennoblement. Moreover, 316L showed a trend similar to Incoloy 825; however, the E<sub>p</sub> ennoblements were significantly more pronounced for both the weldment and the base metal of 316L. |
| first_indexed | 2024-04-24T18:03:20Z |
| format | Article |
| id | doaj.art-41c10ea7535b4f10975c83d0beeb7155 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-04-24T18:03:20Z |
| publishDate | 2024-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-41c10ea7535b4f10975c83d0beeb71552024-03-27T13:52:34ZengMDPI AGMaterials1996-19442024-03-01176133610.3390/ma17061336Microstructures and Corrosion/Localised Corrosion of Stainless Steels, Incoloy and Their Weldments in Nitrite-Containing Chloride EnvironmentsR. K. Singh Raman0W. H. Siew1Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, AustraliaDepartment of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, AustraliaPrompted by the unexpected observation of the pitting of the weldments of a highly corrosion- and pitting-resistant duplex stainless steel, SAF2507, in chloride solutions with nitride addition, the pitting and corrosion resistance of SAF2507 and its weldments were investigated in chloride solutions with and without different levels of nitrite. The Incoloy 825 and 316L austenitic stainless steels were included for the purpose of developing a comparative appreciation. The microstructures of the weldments were characterised, and 316L showed a profound influence of nitrite addition in inhibiting pitting, while ‘meta-stable’ pitting transients that were clearly visible in the chloride solution without nitrite were absent when nitrite was added. Both the parent metal and the weldment of SAF2507 had similar pitting potential (E<sub>p</sub>) in 0.1 M NaCl without nitrite, which was the highest E<sub>p</sub> among the three alloys tested. Additions of nitrite at low concentrations had an inhibitive effect on pitting, whereas higher nitrite contents had a deleterious effect on pitting resistance. On the other hand, Incoloy 825 showed a trend of E<sub>p</sub> ennoblement with an increasing nitrite content of 0.1 M NaCl, and the weldment underwent greater ennoblement. Moreover, 316L showed a trend similar to Incoloy 825; however, the E<sub>p</sub> ennoblements were significantly more pronounced for both the weldment and the base metal of 316L.https://www.mdpi.com/1996-1944/17/6/1336weldmentsduplex stainless steelsIncoloycorrosionlocalised corrosion |
| spellingShingle | R. K. Singh Raman W. H. Siew Microstructures and Corrosion/Localised Corrosion of Stainless Steels, Incoloy and Their Weldments in Nitrite-Containing Chloride Environments Materials weldments duplex stainless steels Incoloy corrosion localised corrosion |
| title | Microstructures and Corrosion/Localised Corrosion of Stainless Steels, Incoloy and Their Weldments in Nitrite-Containing Chloride Environments |
| title_full | Microstructures and Corrosion/Localised Corrosion of Stainless Steels, Incoloy and Their Weldments in Nitrite-Containing Chloride Environments |
| title_fullStr | Microstructures and Corrosion/Localised Corrosion of Stainless Steels, Incoloy and Their Weldments in Nitrite-Containing Chloride Environments |
| title_full_unstemmed | Microstructures and Corrosion/Localised Corrosion of Stainless Steels, Incoloy and Their Weldments in Nitrite-Containing Chloride Environments |
| title_short | Microstructures and Corrosion/Localised Corrosion of Stainless Steels, Incoloy and Their Weldments in Nitrite-Containing Chloride Environments |
| title_sort | microstructures and corrosion localised corrosion of stainless steels incoloy and their weldments in nitrite containing chloride environments |
| topic | weldments duplex stainless steels Incoloy corrosion localised corrosion |
| url | https://www.mdpi.com/1996-1944/17/6/1336 |
| work_keys_str_mv | AT rksinghraman microstructuresandcorrosionlocalisedcorrosionofstainlesssteelsincoloyandtheirweldmentsinnitritecontainingchlorideenvironments AT whsiew microstructuresandcorrosionlocalisedcorrosionofstainlesssteelsincoloyandtheirweldmentsinnitritecontainingchlorideenvironments |