Permeable Coatings and CP Compatibility

2002 ◽  
Author(s):  
Tom Jack ◽  
Fraser King ◽  
Yufeng Cheng ◽  
Robert Worthingham
Keyword(s):  
External Surface ◽  
Protective Coatings ◽  
Impact Damage ◽  
Steel Corrosion ◽  
Barrier Properties ◽  
Surface Coatings ◽  
Line Pipe ◽  
Pipe Surface ◽  
High Impedance ◽  
Environmentally Assisted Cracking

Protective coatings applied to the external surface of line pipe are designed to protect the underlying steel from corrosion over the life of the installation. These coatings are usually used in combination with cathodic protection (CP) to ensure that the steel exposed by coating damage or defects remains protected. The ultimate success of this approach very much depends on the nature, performance and failure mode of the coating. Disbondment of a high impedance coating such as a polyolefin tape can block CP while allowing water access to the underlying steel. Corrosion and near neutral pH SCC can result. In contrast, pinholes or impact damage on coatings such as fusion bonded epoxy allow both CP and water to penetrate to the pipe surface. Coatings that become permeable in service such as asphalt enamels similarly allow protection of the pipe despite a general loss of barrier properties. Because no corrosion or environmentally assisted cracking occurs where adequate CP potentials are sustained, these coatings can be regarded as being “CP compatible”.

scholarly journals The influence of concrete substrate moisture condition on the tensile pull-off strength of protective coatings

2018 ◽  
Vol 199 ◽  
pp. 07016
Author(s):  
Sean Kay ◽  
Hans Beushausen
Keyword(s):  
Bond Strength ◽  
Protective Coatings ◽  
Surface Coatings ◽  
Moisture Condition ◽  
Coating Application ◽  
Substrate Saturation ◽  
Coating Durability ◽  
Substrate Moisture ◽  
Moisture Conditions

A range of different surface coatings are available for the protection of concrete surfaces, typically aimed at reducing the ingress of deleterious substances into the concrete and providing adequate aesthetic appeal on patch-repaired elements. The coating systems are usually of high material quality and perform well when applied and maintained correctly. The long-term success of protective surface coatings is largely a function of application procedures. In particular, coating durability with regards to bond strength and crack resistance is dependent on the preparation of the concrete substrate prior to coating application. This research gives insight into the effects a sound, clean and profiled concrete substrate that is subjected to different moisture conditions has on coating bond strength. The influence of three different methods to precondition concrete substrates on the tensile pull-off strength of two commercial coatings, applied to substrate concrete with various strengths was investigated. The moisture condition was found to have a significant influence on the pull-off strength of the coatings, higher degrees of substrate saturation typically resulting in higher strengths. Similarly, with increasing substrate moisture content, the failure mode increasingly shifted towards substrate cohesion failure.

Nonlinear Harmonic Monitoring of Gouged Dents in Pipeline Specimens Under Cyclic Loading

2006 ◽  
Author(s):  
Alfred E. Crouch ◽  
G. Graham Chell
Keyword(s):  
Cyclic Loading ◽  
Signal Strength ◽  
Hazardous Materials ◽  
Line Pipe ◽  
Pipe Surface ◽  
Depth Data ◽  
Southwest Research Institute ◽  
The Us ◽  
Pressure Changes ◽  
Research Institute

The only in-line inspection technology commercially available for quantitative evaluation of gouged dents is the geometry pig which cannot discriminate between gouged and smooth dents and has no sensitivity to re-rounded dents. Southwest Research Institute® (SwRI®), has been funded by the US Pipeline and Hazardous Materials Safety Administration (PHMSA) and the Gas Research Institute (GRI) through the Pipeline Research Council International (PRCI), to determine the capability of the nonlinear harmonic (NLH) method to characterize the severity of gouged dents, including those that have been re-rounded by internal pressure. This paper describes the NLH method and presents a summary of results from previous work involving burst tests of gouged dents in 24” pipe as a precursor to the current work that involves experiments with four pressure chambers made from 12-inch line pipe under cyclic pressure changes. In each case, internal scanner hardware, driven from outside the pipe, deployed NLH probes against the pipe inner surface, the gouges being on the outer surface. Analysis of the mapped NLH signals on the inner pipe surface revealed residual strain patterns in the pipe and the strain anomalies produced by gouging. The strain anomalies clearly indicated the presence of the gouges on the outside surface, even when they had re-rounded. The signal maps also indicated the length and width of the gouges whereas the signal strength indicated the residual depth. Data are presented showing that the NLH method is capable of ranking the severity of pipeline gouged dents and their propensity for failure under cyclic loading.

scholarly journals Investigations of the Deuterium Permeability of As-Deposited and Oxidized Ti2AlN Coatings

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2085 ◽  
Author(s):  
Lukas Gröner ◽  
Lukas Mengis ◽  
Mathias Galetz ◽  
Lutz Kirste ◽  
Philipp Daum ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Physical Vapor Deposition ◽  
Protective Coatings ◽  
High Vacuum ◽  
Barrier Properties ◽  
Reduction Factor ◽  
Ultra High Vacuum ◽  
Max Phase ◽  
Self Healing ◽  
Α Al2o3

Aluminum containing Mn+1AXn (MAX) phase materials have attracted increasing attention due to their corrosion resistance, a pronounced self-healing effect and promising diffusion barrier properties for hydrogen. We synthesized Ti2AlN coatings on ferritic steel substrates by physical vapor deposition of alternating Ti- and AlN-layers followed by thermal annealing. The microstructure developed a {0001}-texture with platelet-like shaped grains. To investigate the oxidation behavior, the samples were exposed to a temperature of 700 °C in a muffle furnace. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) depth profiles revealed the formation of oxide scales, which consisted mainly of dense and stable α-Al2O3. The oxide layer thickness increased with a time dependency of ~t1/4. Electron probe micro analysis (EPMA) scans revealed a diffusion of Al from the coating into the substrate. Steel membranes with as-deposited Ti2AlN and partially oxidized Ti2AlN coatings were used for permeation tests. The permeation of deuterium from the gas phase was measured in an ultra-high vacuum (UHV) permeation cell by mass spectrometry at temperatures of 30–400 °C. We obtained a permeation reduction factor (PRF) of 45 for a pure Ti2AlN coating and a PRF of ~3700 for the oxidized sample. Thus, protective coatings, which prevent hydrogen-induced corrosion, can be achieved by the proper design of Ti2AlN coatings with suitable oxide scale thicknesses.

Investigation of a Steel Local Corrosion in Chloride-Containing Media

2021 ◽  
Vol 872 ◽  
pp. 7-13
Author(s):  
Varvara Rumyantseva ◽  
Viktoriya Konovalova
Keyword(s):  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Protective Coatings ◽  
Aggressive Medium ◽  
Electrochemical Corrosion ◽  
Steel Corrosion ◽  
Chloride Ions ◽  
Local Corrosion ◽  
Local Damage ◽  
Corrosion Of Steel

Aspects of the development of local corrosion on the metal surface under the influence of aggressive media containing chloride ions are presented. The main mechanisms leading to the formation and development of local damage of the surface of metals are described. The process of electrochemical corrosion of steel under the influence of chloride-containing medium is experimentally investigated. By constructing corrosion diagrams, the main indicators of steel corrosion in a 10% sodium chloride solution were determined, which allows one to judge the rate of development of corrosion processes with local damage to the protective coating and the degree of steel resistance depending on the aggressiveness of the medium. It is shown that protective coatings, such as modified phosphate and oxide-phosphate films, prevent the penetration of an aggressive medium to the surface of the protected metal and, accordingly, the anodic dissolution of the metal.

Ring Expansion Testing Innovations: Hydraulic Clamping and Strain Measurement Methods

2020 ◽  
Author(s):  
William Walsh ◽  
Sandeep Abotula ◽  
Bharath Konda
Keyword(s):  
Tensile Testing ◽  
Point Contact ◽  
Ring Expansion ◽  
Hydraulic Pressure ◽  
Stress Strain ◽  
Line Pipe ◽  
Pipe Surface ◽  
Expansion Test ◽  
Round Bar ◽  
Dial Indicator

Abstract Ring expansion testing is one of the three accepted methods in API 5L for the measurement of yield strength for line pipe. The other two are flattened-strap tensile testing and round-bar tensile testing. A novel-concept ring expansion test machine has recently been commissioned which uses hydraulic pressure to clamp the top and bottom pressure-reacting plates rather than a traditional bolting arrangement. The benefit of hydraulic clamping is vastly reduced set-up times. This paper describes the design approach and the pitfalls that were overcome in commissioning the ring expansion test unit. Expansion measurements are taken using two different methods: a chain extensometer and an LVDT with a band wrapping the circumference of the pipe. Both approaches are used simultaneously to generate and compare two stress-strain curves for one pressure test. In addition, a 3-Point contact approach is developed to determine the hoop strain during pipe expansion. The 3-point contact approach is an attempt to infer the full hoop expansion behavior by measuring the radius change over a segment of the circumference. The device has two rollers which contact the pipe surface while a dial indicator midway between measures the radius change. As the pipe expands, the rollers maintain contact with the pipe surface while the dial indicator records the change in radius. Tests are performed on HFI, SAWL, and SAWH pipes ranging in outer diameter from 20-inch (508 mm) to 48-inch (1219 mm) and wall thicknesses from 0.375-inch (9.5 mm) to 0.969-inch (24.4 mm). The differences in the stress-strain behavior of these pipe forms are described and related to the residual-stress profiles generated by their respective manufacturing operations. The comparison to flattened-strap and round-bar tensile results are presented in a companion paper. The results of the 3-Point contact approach show that the radius change during early stages of expansion are not uniform around the pipe circumference and different patterns are observed in the HFI, SAWL, and SAWH pipe forms.

A Finite Element Analysis of Temperature Profiles and Cooling Rates of ERW Pipes during TIG Welding

2013 ◽  
Vol 13 (4) ◽  
pp. 221-232
Author(s):  
Tathagata Bhattacharya ◽  
Asish Bandyopadhyay ◽  
Pradip Kumar Pal
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Temperature Profile ◽  
External Surface ◽  
Tig Welding ◽  
Graphical Form ◽  
Welding Parameters ◽  
Cooling Rates ◽  
Pipe Surface ◽  
Element Modeling

AbstractThe present investigation deals with the determination of temperature profile and subsequent cooling rates of certain points on the external surface of an ERW pipe with the help of ANSYS Finite Element Modeling and Analysis method, under simulated TIG welding conditions. A TIG welding condition for an ERW pipe is first simulated through ANSYS Finite Element Modeling. The physical and material properties along with the dimensions and size of the ERW pipe are all included in the modeling part. The TIG welding arc is simulated as a point heat source of a given power traversing the periphery of the pipe surface during welding. In the ANSYS program, after modeling the TIG welding problem, the same is run in the post – processing analysis part to get the temperature profile along the external surface of the pipe at various time intervals from the start of the welding. The rate of cooling of a few particular nodes on the modeled pipe surface, from the start of welding to the completion of one welding pass is also studied and results are indicated in graphical form. Later, these cooling rates on the modeled pipe surface are compared with those of an exactly similar ERW pipe, physically welded by TIG welding method in the workshop under similar welding conditions and welding parameters.

Corrosion Protective Coatings: Fabrication of Sputtered CeO2-La2O3 and La2O3-CeO2 Bilayers

2019 ◽  
Author(s):  
Domínguez-Crespo Miguel Antonio ◽  
Brachetti-Sibaja Silvia ◽  
Torres-Huerta Aidé ◽  
Onofre Edgar ◽  
López-Oyama Ana ◽  
...  
Keyword(s):  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Protective Coatings ◽  
Barrier Properties ◽  
Average Roughness ◽  
Protection Efficiency ◽  
Substrate Composition ◽  
Deposition Parameters ◽  
Potentiodynamic Curves ◽  
The Relationship

This entry provides a comparative study on the corrosion protection efficiency of Ce, La films as well as Ce/La- and La/Ce-bilayered coatings deposited onto AA7075 and AA6061 substrates by the radio frequency magnetron sputtering technique. The coating thickness ranged from ~12 to 835 nm, which changed with the deposition parameters and substrate composition. The relationship between microstructure, roughness, and electrochemical performance is examined. The reactivity and crystallinity of rare earth (RE) films can be tailored by adjusting the sputtering parameters. Sputtered La films with a thickness of ~390 nm and an average roughness of 66 nm showed the best corrosion protection properties in chloride medium as determined by potentiodynamic curves and electrochemical impedance spectroscopy. The method to obtain RE-bilayered coatings, i.e., La/Ce or Ce/La as well as the substrate composition and applied power, conditioned their inhibition properties. The RE-bilayered coatings displayed better barrier properties than Ce films, which were worser than those featured by La films.

The Role of Soil Data in Pipeline Integrity

2004 ◽  
Author(s):  
James E. Marr ◽  
Neil Bates ◽  
David Portelance ◽  
Scott Farthing
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Measurement Techniques ◽  
Corrosion Cracking ◽  
Soil Survey ◽  
Line Pipe ◽  
Pipe Surface ◽  
Use Of Data ◽  
External Corrosion ◽  
Buried Point

Since the early 20th century, researchers and engineers have been using soils information to address corrosion issues on buried metallic materials. While this area of research was quite active from the 1920’s to the 1950’s, soils related corrosion pipeline research was declining until the mid eighties. For the non-soil scientist this area is complex and disruptive since there is usually no easy equation or consistent answer from buried point to buried point. Historically, the pipeline industry has developed coating systems that effectively place a barrier between the soil environment and the pipe surface. Over time, these coatings can deteriorate to such a level that the environment can either migrate through the coating or come in direct contact with the pipe surface. The second level of protection used in the defense of the pipe from the environment is the cathodic protection (CP) system. These systems can also deteriorate, but they can be monitored through measurement techniques at a given interval. The CP system can provide an adequate level of protection, thus minimizing potential pipeline integrity threats such as external corrosion and stress corrosion cracking. This paper will present a historical overview of the use of soils and soil survey information and will provide an overview our experiences related to the use of data effecting external corrosion and stress corrosion cracking of line pipe steels.

Field Assessment of FBE-Coated Pipelines and the Implications for Stress Corrosion Cracking

2002 ◽  
Author(s):  
Fraser King ◽  
Yufeng Cheng ◽  
Linda Gray ◽  
Brent Drader ◽  
Robert Sutherby
Keyword(s):  
High Performance ◽  
Electrochemical Impedance ◽  
Surface Preparation ◽  
Field Measurements ◽  
Barrier Properties ◽  
Pipe Surface ◽  
Good Surface ◽  
Surface Residual Stresses ◽  
Eis Measurements ◽  
Term Performance

One proposed method for preventing the initiation of SCC on pipelines is through the use of high-performance coatings in conjunction with effective cathodic protection. High-performance coatings include fusion bonded epoxy (FBE), urethanes, liquid epoxies, extruded polyethylene, and multi-layer coatings. This paper reports the results of a CEPA-sponsored project to determine the long-term performance of FBE coatings on underground pipelines using in situ field measurements. The barrier properties of FBE coatings were measured after several years field service using Electrochemical Impedance Spectroscopy (EIS). Measurements were made on four FBE-coated pipelines that had been exposed for periods of between 5 and 20 years. The coatings studied included three different formulations from two different manufacturers. A variety of site, soil and CP conditions were also examined. The combination of EIS measurements and analyses of trapped water samples demonstrated that the FBE coatings continued to perform well after having been exposed for up to 20 years. Although some blistering and disbondment was observed in some cases as a result of poor application and storage procedures, in all cases the pipe surface was still protected either by the coating itself or by the joint action of the CP system and the CP-compatible FBE coating. The results of this study provide strong evidence that FBE-coated pipelines should not be susceptible to the initiation of SCC, due to (i) the barrier properties of the coating, (ii) the CP-compatible nature of the coating, and (iii) good surface preparation techniques that involve the removal of millscale and the introduction of compressive surface residual stresses.

scholarly journals Self-Healing Coating on Aluminium Alloy (AA2014) using a Sol - Gel Process

2021 ◽  
Vol 9 (VI) ◽  
pp. 293-300
Author(s):  
Saurabh Kumar Jha
Keyword(s):  
Aluminium Alloy ◽  
Electrochemical Impedance ◽  
Ph Value ◽  
Sol Gel ◽  
Low Frequency ◽  
Barrier Properties ◽  
Immersion Test ◽  
Self Healing ◽  
High Impedance ◽  
Sol Gel Process

In this paper, a new doping concept has been improved which shows self-healing properties by sustained release of corrosion inhibitors in a carrier system. The anti-corrosive properties of (AA2014) aluminium alloy was tested by electrochemical impedance spectroscopy. The sol-gel coating doped with both inorganic and organic inhibitors gives a satisfying result. Releasing the event of inhibitor depends on the pH value of the corrosion environment. The barrier properties of the best coating divulge by high pore resistance with having high impedance value at low frequency. The immersion test confirmed that double doping concept is valuable also for long immersion test.

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