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| Project Number | 576 |
| Date of Summary | September 30, 2009 |
| Subject | Measurement of the Effect of Magnetism on Hydrogen Cracking Susceptibility of Pipeline Steels |
| Performing Activity | Colorado School of Mines (CSM) |
| Principal Investigator | Dr. David Olson |
| Contracting Agency | Minerals Management Service |
| Estimated Completion | August 31, 2010 |
| Description | This research serves to study hydrogen damage susceptibility (i.e., cracking and pitting) of steel pipe due to the effect on magnetism (including remnant magnetism) in combination with cathodic protection. The current phase (Phase III) of research will build on findings made during phase I that ended in December 2005 (TAR Study 487) and Phase II that ended in February 2007 (TAR Study 522). CSM found evidence of hydrogen cracking and surface pitting due to hydrogen absorption from cathodic protection under strong magnetic fields; magnetic levels typically found in many pipeline integrity tools used by industry. Due to concerns for these findings and the implications to industry’s use of internal pipeline inspection integrity tools (i.e., MFL-tools), the DOT and MMS asked that CSM solicit comments from Industry as to CSM’s findings and the need for additional analysis. CSM held a series of meetings for that purpose with representatives from Industry, Academia, the Federal Government (NIST, PHMSA, and MMS) and representatives from the Norwegian Pipeline Industry and based on those discussion received support to proceed with Phase III for further test analysis to (in)validate the findings using actual field conditions under a Joint Industry Project. Due to concerns for these findings and the implication it may have for industry’s continued use of magnetic flux (MFL) tools for internal pipeline inspections, Phase III will focus on further laboratory trials as well as field measurement of MFL inspected pipe to determine actual field measurements. |
| Progress |
The magnetic, mechanical, and magnetocorrosion behavior of pipeline steels
have been measured and the correlations have been described between these
properties. The described results indicate electromagnetic enhanced
corrosion can be a concern in situations in which significant
electromagnetic fields are experienced. From laboratory tests, magnetic flux
leakage testing and other sources of significant magnetic remanence appear
likely to actively raise the hydrogen content and likelihood of
hydrogen-related damage, particularly in older cathodic protected coated
pipelines. Thermodynamic and kinetic models were introduced to assist in
explaining the observed data.
Contractor held a 2-day meeting on September 14 & 15th, 2009 to present their work on this and other studies. Findings reported during meeting include: • Magnetic fields can cause an increase in the corrosion, pitting and cracking behavior, and hydrogen content, • A remanence can exists even at low applied magnetic fields, • Kinetic models (EM stirring), give a possible explanation for the magnetocorrosion behavior, • Shifts in EIS measurements in an applied magnetic field suggests a stirring mechanism in the electrolyte (MHD) and also evidence of scale formation, • Some suggestions of MHD stirring assists in hydrogen ion transport to the steel surface, • Lorentz forces assist in hydrogen transport from the metal surface into the bulk metal, suggesting enhanced hydrogen concentrations. |
| Report | |
| AA (7961 KB PDF) | 1. Measurement of the Effect of Magnetism on Hydrogen Cracking Susceptibility of Pipeline Steels, Progress Report by Dr. David L. Olson, Dr. Brajendra Mishra, and J. A. Boubidoux, Colorado School of Mines, Golden, CO, November 2008. |
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Last Updated:
10/21/2009,
08:21 AM |
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