Server maintenance is scheduled for Saturday, December 21st between 6am-10am CST.

During that time, parts of our website will be affected until maintenance is completed. Thank you for your patience.

Menu
Search
Filters
Close
Menu

11268 Control of Preferential Weld Corrosion of X65 Pipeline Steel in Flowing Brines Containing Carbon Dioxide

Picture for 11268 Control of Preferential Weld Corrosion of X65 Pipeline Steel in Flowing Brines
Available for download
Product Number: 51300-11268-SG
ISBN: 11268 2011 CP
Author: Mylene Martinez, Khaled Alawadhi, Michael Robinson, Graham Nelson and Andrew MacDonald
Publication Date: 2011
$0.00
$20.00
$20.00
This paper investigates the effectiveness of two typical oilfield corrosion inhibitors in controlling preferential weld corrosion of X65 pipeline steel in artificial seawater saturated with carbon dioxide at one bar pressure. A rotating cylinder electrode apparatus was designed so that weld metal, heat affected zone and parent material could be tested in high shear stress conditions. The galvanic currents flowing between the weld regions were recorded using zero-resistance ammeters and their self-corrosion rates were obtained by linear polarization resistance measurements.

In uninhibited conditions, the weld metal and heat affected zone were cathodic to parent material and no localised corrosion occurred. However, 30 ppm of inhibitor caused a current reversal at low shear stress, resulting in preferential corrosion of the weld metal. At high shear stress, the currents increased and further reversals occurred. The inhibitors were more effective in controlling the self-corrosion rates of the parent material than weld metal and heat affected zone. Total corrosion rates were calculated from the sum of the galvanic and self-corrosion contributions and the efficiencies of the two inhibitors were compared. It was concluded that preferential weld corrosion was caused by unstable conditions in which the inhibitor film was removed selectively from weld metal and heat affected zone but remained effective on the parent material.

Key words: weld corrosion, carbon steel, inhibitor, carbon dioxide
This paper investigates the effectiveness of two typical oilfield corrosion inhibitors in controlling preferential weld corrosion of X65 pipeline steel in artificial seawater saturated with carbon dioxide at one bar pressure. A rotating cylinder electrode apparatus was designed so that weld metal, heat affected zone and parent material could be tested in high shear stress conditions. The galvanic currents flowing between the weld regions were recorded using zero-resistance ammeters and their self-corrosion rates were obtained by linear polarization resistance measurements.

In uninhibited conditions, the weld metal and heat affected zone were cathodic to parent material and no localised corrosion occurred. However, 30 ppm of inhibitor caused a current reversal at low shear stress, resulting in preferential corrosion of the weld metal. At high shear stress, the currents increased and further reversals occurred. The inhibitors were more effective in controlling the self-corrosion rates of the parent material than weld metal and heat affected zone. Total corrosion rates were calculated from the sum of the galvanic and self-corrosion contributions and the efficiencies of the two inhibitors were compared. It was concluded that preferential weld corrosion was caused by unstable conditions in which the inhibitor film was removed selectively from weld metal and heat affected zone but remained effective on the parent material.

Key words: weld corrosion, carbon steel, inhibitor, carbon dioxide
Product tags
Also Purchased
Picture for 05277 Preferential Weld Corrosion: Effects of
Available for download

05277 Preferential Weld Corrosion: Effects of Weldment Microstructure and Composition

Product Number: 51300-05277-SG
ISBN: 05277 2005 CP
Author: Chi-Ming Lee and Paul Woollin, TWI Ltd.
$20.00
Picture for Evaluation of Preferential Weld Corrosion Susceptibility and Its Mitigation in Slightly Sour Conditions
Available for download

Evaluation of Preferential Weld Corrosion Susceptibility and Its Mitigation in Slightly Sour Conditions

Product Number: 51315-5640-SG
ISBN: 5640 2015 CP
Author: Ray Case
Publication Date: 2015
$20.00

Preferential Weld Corrosion (PWC) susceptibility was studied in a slightly sour wet gas piping system using electrochemical methods based on the “hockey puck” technique. Several corrosion inhibitors were evaluated to assess their performance in suppressing PWC.
Picture for 05276 Corrosion Loop Studies of Preferential Weld
Available for download

05276 Corrosion Loop Studies of Preferential Weld Corrosion and Its Inhibition in CO2 Environments

Product Number: 51300-05276-SG
ISBN: 05276 2005 CP
Author: Egil Gulbrandsen and Arne Dugstad, Institute for Energy Technology
$20.00
Categories
Industry
Recently viewed
Popular tags
View all

Association for Materials Protection and Performance

© AMPP All Rights Reserved.
Membership Terms of Content Use
Contact Customer Support