Skip Navigation Minerals Management Service Minerals Management Service MMS Home pagesSearchMMS Topic IndexAbout MMSWhat’s NewOffshore Energy and Minerals Management United States Department of the Interior
TA&R Home PageTA&R International Home PagesTA&R Oil Spill Research HomeTA&R Research Projects HomeTA&R Workshops HomeTA&R Safety Home
Project Number 576
Date of Summary June 3, 2008
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. This third phase 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).  During phase I, 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 further test analysis to (in)validate the findings using actual field conditions under a Joint Industry Project.
Progress

To determine the effect of a magnetic field on hydrogen content in pipeline steel, a series of cathodic hydrogen charging experiments were performed on steel grade X52. A series of experiments was run with a magnetic field of 0.6 T and second series without the influence of a magnetic field.  The results indicate that a magnetic field has a significant effect on the amount of absorbed hydrogen concentration in pipeline steel. The results obtained from the experiments completed during this research are in good agreement with the experimental results obtained by Sanchez (see F.J. Sanchez, “An Assessment of Magnetization Effect on Hydrogen Induced Cracking For Thick Walled Pipelines”, Colorado School of Mines Ph.D. Thesis (2005).

Modeling of the underlying effects of magneto corrosion behavior has coupled electromagnetic perturbations to alterations in the electrochemical behavior, including the Helmholtz and Gouy-Chapman layer. These perturbations result in enhanced anodic and cathodic behavior, resulting in both increase in hydrogen ingress and pitting and cracking behavior.

Findings to date include:

1. A continuous magnetic field has a significant effect on the absorbed hydrogen concentration in pipeline steels.

2. A continuous magnetic field has been observed to alter the nucleation and growth of bubbles on the sample surface and also alter the flow path of the bubbles.

3. The observed electrochemical impedance measurements correspond with the modeling of the magneto corrosion phenomena, and indicate a significant change in the impedance in the presence of a magnetic field.

4. A preliminary field investigation was made to evaluate instrumentation performance and requirements for field experimental assessment.

 

Privacy | Disclaimers | Accessibility | Topic Index | FOIA

Last Updated: 07/28/2008, 01:35 PM