Novel Insights into Trenching of Ni-Containing Low Alloy Steel in Simulated Sour Conditions with Sodium Thiosulfate

There is interest in using thiosulfate as a simulant for research on the sour corrosion of carbon steel because of its safety compared to the original sour test using H2S gas. The effect of Ni on trenching behavior using a simulated sour solution containing 10−3 M Na2S2O3 with pH 4.0 was investigate...

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Main Authors: Samusawa, Itaru, Shimamura, Junji, Al Helal, Ammar, Sapanathan, Thaneshan
Format: Journal Article
Published: 2025
Online Access:http://purl.org/au-research/grants/arc/LE130100053
http://hdl.handle.net/20.500.11937/97087
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author Samusawa, Itaru
Shimamura, Junji
Al Helal, Ammar
Sapanathan, Thaneshan
author_facet Samusawa, Itaru
Shimamura, Junji
Al Helal, Ammar
Sapanathan, Thaneshan
author_sort Samusawa, Itaru
building Curtin Institutional Repository
collection Online Access
description There is interest in using thiosulfate as a simulant for research on the sour corrosion of carbon steel because of its safety compared to the original sour test using H2S gas. The effect of Ni on trenching behavior using a simulated sour solution containing 10−3 M Na2S2O3 with pH 4.0 was investigated using a four-point bending test in various applied and open-circuit potential conditions. In this study, x-ray diffraction and scanning electron microscopy were used to characterize steel surfaces after testing. The results showed that Ni promotes trenching and is especially favored by anodic constant potential conditions. On the other hand, the amount of H2S generated by the dissociation and reaction of Na2S2O3 with the metal surface during the test was also influenced by Ni content and applied potential. Specifically, the alloying of Ni and the increase in potential promoted H2S formation. Moreover, the H2S concentrations on the steel surface during the tests at pH 4.0 in this study were estimated to correspond to the sour region 0, which is lower than previously reported test at pH 2.7. This indicates that the simulated sour test is more difficult to control H2S concentration than in our earlier sour test with actual H2S gas and found that the amount of H2S generated on each test condition must be taken into consideration carefully when investigating the corrosion behavior in a simulated sour solution containing Na2S2O3. Based on the experimental findings, the trenching mechanism of Ni-containing steel low alloy steel under 10−3 M Na2S2O3 containing acid brines with pH4.0 is proposed.
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institution Curtin University Malaysia
institution_category Local University
last_indexed 2025-11-14T11:47:41Z
publishDate 2025
recordtype eprints
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spelling curtin-20.500.11937-970872025-03-04T02:40:33Z Novel Insights into Trenching of Ni-Containing Low Alloy Steel in Simulated Sour Conditions with Sodium Thiosulfate Samusawa, Itaru Shimamura, Junji Al Helal, Ammar Sapanathan, Thaneshan There is interest in using thiosulfate as a simulant for research on the sour corrosion of carbon steel because of its safety compared to the original sour test using H2S gas. The effect of Ni on trenching behavior using a simulated sour solution containing 10−3 M Na2S2O3 with pH 4.0 was investigated using a four-point bending test in various applied and open-circuit potential conditions. In this study, x-ray diffraction and scanning electron microscopy were used to characterize steel surfaces after testing. The results showed that Ni promotes trenching and is especially favored by anodic constant potential conditions. On the other hand, the amount of H2S generated by the dissociation and reaction of Na2S2O3 with the metal surface during the test was also influenced by Ni content and applied potential. Specifically, the alloying of Ni and the increase in potential promoted H2S formation. Moreover, the H2S concentrations on the steel surface during the tests at pH 4.0 in this study were estimated to correspond to the sour region 0, which is lower than previously reported test at pH 2.7. This indicates that the simulated sour test is more difficult to control H2S concentration than in our earlier sour test with actual H2S gas and found that the amount of H2S generated on each test condition must be taken into consideration carefully when investigating the corrosion behavior in a simulated sour solution containing Na2S2O3. Based on the experimental findings, the trenching mechanism of Ni-containing steel low alloy steel under 10−3 M Na2S2O3 containing acid brines with pH4.0 is proposed. 2025 Journal Article http://hdl.handle.net/20.500.11937/97087 10.5006/4651 http://purl.org/au-research/grants/arc/LE130100053 fulltext
spellingShingle Samusawa, Itaru
Shimamura, Junji
Al Helal, Ammar
Sapanathan, Thaneshan
Novel Insights into Trenching of Ni-Containing Low Alloy Steel in Simulated Sour Conditions with Sodium Thiosulfate
title Novel Insights into Trenching of Ni-Containing Low Alloy Steel in Simulated Sour Conditions with Sodium Thiosulfate
title_full Novel Insights into Trenching of Ni-Containing Low Alloy Steel in Simulated Sour Conditions with Sodium Thiosulfate
title_fullStr Novel Insights into Trenching of Ni-Containing Low Alloy Steel in Simulated Sour Conditions with Sodium Thiosulfate
title_full_unstemmed Novel Insights into Trenching of Ni-Containing Low Alloy Steel in Simulated Sour Conditions with Sodium Thiosulfate
title_short Novel Insights into Trenching of Ni-Containing Low Alloy Steel in Simulated Sour Conditions with Sodium Thiosulfate
title_sort novel insights into trenching of ni-containing low alloy steel in simulated sour conditions with sodium thiosulfate
url http://purl.org/au-research/grants/arc/LE130100053
http://hdl.handle.net/20.500.11937/97087