A Conceptual Model for the Interaction between Carbon Content and Manganese Sulphide Inclusions in the Short-Term Seawater Corrosion of Low Carbon Steel
The critical role of manganese sulphide (MnS) inclusions for the initiation of the short-term growth of pitting or localized corrosion of low carbon steels has long been recognized. Classical results show that pitting probability and pitting severity increases with increased sulphide concentration f...
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MDPI AG
2016-05-01
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| Series: | Metals |
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| Online Access: | http://www.mdpi.com/2075-4701/6/6/132 |
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| author | Robert E. Melchers Igor A. Chaves Robert Jeffrey |
| author_facet | Robert E. Melchers Igor A. Chaves Robert Jeffrey |
| author_sort | Robert E. Melchers |
| collection | DOAJ |
| description | The critical role of manganese sulphide (MnS) inclusions for the initiation of the short-term growth of pitting or localized corrosion of low carbon steels has long been recognized. Classical results show that pitting probability and pitting severity increases with increased sulphide concentration for low carbon steels as a result of magnesium sulphides acting as local cathodes for initiating pitting corrosion. However, the iron carbides (cementite) in steels can also act as local cathodes for initiation of pitting corrosion. Herein it is proposed that there is competition between pits for cathodic area and that this will determine the severity of pitting and general corrosion observed in extended exposures. Preliminary experimental data for immersion exposures of up to 56 days in natural seawater of three low carbon steels show, contrary to conventional wisdom, greater pit depths for the steels with lower S content. However, the pit depth results are consistent with lower C/S ratios. This is considered to support the concept of cathodic competition between C and S. It is proposed that this offers explanations for a number of other phenomena, including the thus far unexplained apparently higher reactivity of some MnS inclusions. |
| first_indexed | 2024-12-11T05:55:47Z |
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| language | English |
| last_indexed | 2024-12-11T05:55:47Z |
| publishDate | 2016-05-01 |
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| spelling | doaj.art-ea832ddfe9d24ac88721c2ae00e4837c2022-12-22T01:18:41ZengMDPI AGMetals2075-47012016-05-016613210.3390/met6060132met6060132A Conceptual Model for the Interaction between Carbon Content and Manganese Sulphide Inclusions in the Short-Term Seawater Corrosion of Low Carbon SteelRobert E. Melchers0Igor A. Chaves1Robert Jeffrey2Centre for Infrastructure Performance and Reliability, The University of Newcastle, Newcastle 2308, AustraliaCentre for Infrastructure Performance and Reliability, The University of Newcastle, Newcastle 2308, AustraliaCentre for Infrastructure Performance and Reliability, The University of Newcastle, Newcastle 2308, AustraliaThe critical role of manganese sulphide (MnS) inclusions for the initiation of the short-term growth of pitting or localized corrosion of low carbon steels has long been recognized. Classical results show that pitting probability and pitting severity increases with increased sulphide concentration for low carbon steels as a result of magnesium sulphides acting as local cathodes for initiating pitting corrosion. However, the iron carbides (cementite) in steels can also act as local cathodes for initiation of pitting corrosion. Herein it is proposed that there is competition between pits for cathodic area and that this will determine the severity of pitting and general corrosion observed in extended exposures. Preliminary experimental data for immersion exposures of up to 56 days in natural seawater of three low carbon steels show, contrary to conventional wisdom, greater pit depths for the steels with lower S content. However, the pit depth results are consistent with lower C/S ratios. This is considered to support the concept of cathodic competition between C and S. It is proposed that this offers explanations for a number of other phenomena, including the thus far unexplained apparently higher reactivity of some MnS inclusions.http://www.mdpi.com/2075-4701/6/6/132manganesesulphidescathodescarboncompetition |
| spellingShingle | Robert E. Melchers Igor A. Chaves Robert Jeffrey A Conceptual Model for the Interaction between Carbon Content and Manganese Sulphide Inclusions in the Short-Term Seawater Corrosion of Low Carbon Steel Metals manganese sulphides cathodes carbon competition |
| title | A Conceptual Model for the Interaction between Carbon Content and Manganese Sulphide Inclusions in the Short-Term Seawater Corrosion of Low Carbon Steel |
| title_full | A Conceptual Model for the Interaction between Carbon Content and Manganese Sulphide Inclusions in the Short-Term Seawater Corrosion of Low Carbon Steel |
| title_fullStr | A Conceptual Model for the Interaction between Carbon Content and Manganese Sulphide Inclusions in the Short-Term Seawater Corrosion of Low Carbon Steel |
| title_full_unstemmed | A Conceptual Model for the Interaction between Carbon Content and Manganese Sulphide Inclusions in the Short-Term Seawater Corrosion of Low Carbon Steel |
| title_short | A Conceptual Model for the Interaction between Carbon Content and Manganese Sulphide Inclusions in the Short-Term Seawater Corrosion of Low Carbon Steel |
| title_sort | conceptual model for the interaction between carbon content and manganese sulphide inclusions in the short term seawater corrosion of low carbon steel |
| topic | manganese sulphides cathodes carbon competition |
| url | http://www.mdpi.com/2075-4701/6/6/132 |
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