Joshua E. Jackson

REAL‐TIME LOW FREQUENCY IMPEDANCE MEASUREMENTS FOR DETERMINATION OF HYDROGEN CONTENT IN PIPELINE STEEL

The assessment of hydrogen content in pipeline steel is an essential requirement to monitor loss of pipe integrity with time and to prevent failures. The use of pipeline steels of increasing strength significantly reduces the threshold hydrogen concentration for hydrogen cracking. Cathodic protection and corrosion processes both contribute to accumulation of hydrogen as a function of time, which may eventually meet the cracking criteria. New and unique methodologies based on electronic property measurements offer the pipeline industry advanced non‐destructive tools to provide quantified in‐situ hydrogen content measurements in real‐time. The use of low frequency impedance measurements as a non‐contact sensor has been demonstrated for real‐time determination of hydrogen content in coated pipeline steel specimens in the laboratory. Scale‐up to field measurements is in progress, and the development and use of a field sensor are discussed.

THE FUTURE OF MICROSTRUCTURAL CHARACTERIZATION: AN ELECTRONIC METALLOGRAPHY LABORATORY

The ability to assess microstructure through quantitative nondestructive evaluation is possible through intelligent use of combinations of intrinsic property measurements. A microstructure rule must be developed to identify the number of measurements necessary to characterize phases and their topology. This paper suggests rules and new methods to classify materials based on electronic structure and response to physical perturbations. An electronic metallographic laboratory that can rapidly characterize materials in‐situ on functional or structural materials is in our future.

ASSESSING RESIDUAL STRESS ON MACHINED URANIUM USING NONDESTRUCTIVE THERMOELECTRIC POWER COEFFICIENT AND INDUCED IMPEDANCE MEASUREMENTS

A nondestructive assessment of the residual stress on machined uranium surfaces is provided by the correlation of thermoelectric power coefficient and induced impedance measurements. Thermoelectric power measurements utilize a contact nondestructive probe to assess defects in the near surface. Thermoelectric power measured with a high impedance nanovoltmeter is very sensitive to effective mass of the electron, which is a measure of perturbations of the periodic lattice such as strain. Induced impedance analysis utilizes a non‐contact nondestructive coil probe arrangement that can measure various depths into a material depending on the frequency induced. Induced impedance measures the change in electron scatter from a material that arises from lattice defects and periodic lattice strains. Uranium specimens were four‐point bend tested to achieve known surface stresses, which were measured by thermoelectric power and induced impedance to achieve a uranium stress calibration curve. Following calibration, the ...

DEVELOPMENT OF ELECTROMAGNETIC TECHNIQUES FOR HYDROGEN CONTENT ASSESSMENT IN COATED LINEPIPE STEEL

With the introduction of new higher strength steels operating at higher pressure, the need for characterization of hydrogen content in high strength steel pipelines is timely for the pipeline industry. The higher‐strength steel pipelines have higher susceptibility to hydrogen damage. Through the use of low‐frequency induced current impedance measurements, a new non‐contact sensor has been developed for real‐time determination of diffusible hydrogen content in coated pipeline steel. A measurement scheme to separate variables associated with pipelines is discussed. This electromagnetic technique allows for a rapid, non‐destructive assessment of hydrogen accumulation in coated steel line pipe and thus an evaluation of the pipeline integrity.

Development of Graded-Architecture Mullite Thermal Barrier Coating on Mo-Si-B Turbine Materials

A unique organic electrodeposition technique has been developed which allows rapid, smooth, and consistent coating application at low temperatures, low voltages, and with no pollutants. Precursor coatings of Aluminum, Al-Si, and Al-Mullite have been applied to Mo-Si-B turbine materials through immersion deposition and organic electrolytic cathodic deposition in an ionic liquid. These coatings were applied in protective atmosphere boxes and followed by low-temperature annealing to create a graded precursor layer. A graded precursor layer is desirable to minimize thermal shock, improve adhesion and achieve oxidation protection. The reactions across the interface region were characterized to assist in creation of the proper graded precursor layers for mullite formation. The optimal coating deposition method and composition has been assessed. High-temperature oxidation is being performed to form graded corrosion-resistant mullite thermal barrier coatings. The optimum deposition, annealing, and oxidation parameters will be characterized to achieve the proper thickness and compositional gradient of the thermal barrier coating. Coatings with various compositions and compositional gradients in the Mo-Si-B substrate and mullite layer are being assessed in a high-temperature simulated burner environment. Additional protective layers, such as barium-strontium-alumino-silicate (BSAS) are being developed to extend service life.Copyright

Development of a Novel Electromagnetic Quantitative Residual Stress Sensor for Characterization of Steel Pipeline Mechanical Damage

Nondestructive residual stress mapping of damage in pipeline steel has been demonstrated as a new approach for pipeline integrity management. The handheld system for rapid characterization pipelines has been used on dents and wrinkles, two of the most common forms of mechanical deformation. The ability to compare residual stresses with design stresses will allow for a much more accurate criteria for use in fitness-for-service and improved modeling of pipeline stresses. As the capabilities of in-line inspection technologies continue to improve, operators are often faced with thousands of indications that require examination. Accurate assessment of residual stresses will provide a more effective method of combatting the most common form of pipeline failures, mechanical damage.The residual stresses associated with the mechanical damage forms the basis for the nucleation and growth of cracks at areas with the highest residual stresses. Quantitative, real-time knowledge of the through-thickness residual stress levels associated with the mechanical damage will enable enhanced Risk-Based Inspection and drastically improve pipeline integrity. The development of a non-destructive, quantified residual stress measurement system to evaluate the damage severity on pipeline steels through the structural coatings (without any removal) will enable improved integrity assessment and reduce the number of unnecessary removal and replacement activities. The development of a real-time, through-thickness residual stress sensor to assess steel pipeline mechanical damage is presented in this paper.Copyright

A FUNDAMENTAL ANALYSIS OF LOW FREQUENCY IMPEDANCE PHENOMENON: APPLICATION TO HYDROGEN CONTENT ASSESSMENT OF COATED LINEPIPE STEEL WELDMENTS

Nondestructive hydrogen content assessment of coated linepipe steel weldments via low frequency impedance measurements has been realized both in the laboratory and the field. A fundamental analysis of the plausibility of localized hydrogen‐induced lattice strain detection in linepipe steel through low frequency impedance measurements is presented. Theoretical explanations of low frequency impedance measurements include free electron theory, quantum mechanics, and RKKY theory.

Development of a Non-Contact Hydrogen Sensor for Coated Pipeline Steel Weldments

Only a few parts per million of hydrogen are needed to produce detrimental results in higher strength pipeline steels. The cost of removal and subsequent replacement of a pipeline coating is high; thus a working hydrogen detector for field measurements must operate through the pipeline coating. An in-field sensor must utilize technology that provides rapid (or real-time) non-contact nondestructive measurements. Nondestructive low frequency impedance measurements can be used to determine hydrogen content in operating pipeline steel and weldments as well as through structural coatings. Low frequency impedance measurements have been correlated to hydrogen content in pipeline steel both in the laboratory and in the field. The use of real-time low frequency impedance measurements to monitor hydrogen content in coated steel weldments is presented.© 2010 ASME

ASSESSMENT OF MAGNETOCORROSION BY MAGNETIC AND IMPEDANCE MEASUREMENTS

Magnetocorrosion is the altered corrosion behavior, including changes in hydrogen ingress, experienced in the presence of a magnetic field. Laboratory electrochemical hydrogen charging measurements in the presence of a magnetic field indicate a significant increase in magnetocorrosion (including hydrogen content, pitting, and cracking) compared to unmagnetized charging. This research evaluated the thermodynamics and kinetics of corrosion, and evaluated the correlation of magnetocorrosion to microstructure, mechanical properties, and magnetic properties. Proposed thermodynamic models including the effects of spin alignment, magnetostriction, and solute‐strain have been developed.

Engineered Weld Design: Are Composite Welds Likely in the Future?

Utilizing alternating welding process parameters, deposition practices, and welding consumables, particularly during multiple pass welding, it is possible to improve a variety of weld metal properties. There are available a number of phenomena occurring during welding that allow weld metal designers the ability to generate macro- and micro-structural features amenable to implementation of composite theory. These phenomena include solidification microsegregation during dendrite growth, gas-metal reactions between the selected alternating shielding gas composition and weld pool, and solidification microstructural orientation during welding. Additional methods of producing composite welds including specially designed weld compositions, weld metal solidification modification by arc pulsing, and dual wire deposition may be utilized to achieve single pass and multipass composite weld metal deposition. Composite welds are a potential method to solve challenging demands such as high-toughness at low temperature, creep strength at high temperature, and customized design for corrosion, wear, or cracking resistance.