scholarly journals Hydrogen Accumulation and Distribution in Pipeline Steel in Intensified Corrosion Conditions

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1409 ◽  
Author(s):  
Anatolii I. Titov ◽  
Aleksandr V. Lun-Fu ◽  
Aleksandr V. Gayvaronskiy ◽  
Mikhail A. Bubenchikov ◽  
Aleksei M. Bubenchikov ◽  
...  
Keyword(s):  
Pipeline Steel ◽  
Xrd Analysis ◽  
Impact Testing ◽  
National Standards ◽  
Adsorbed Hydrogen ◽  
Steel Pipeline ◽  
Tension Tests ◽  
Optical Spectrometry ◽  
Hydrogen Accumulation ◽  
Methane Dissociation

Hydrogen accumulation and distribution in pipeline steel under conditions of enhanced corrosion has been studied. The XRD analysis, optical spectrometry and uniaxial tension tests reveal that the corrosion environment affects the parameters of the inner and outer surface of the steel pipeline as well as the steel pipeline bulk. The steel surface becomes saturated with hydrogen released as a reaction product during insignificant methane dissociation. Measurements of the adsorbed hydrogen concentration throughout the steel pipe bulk were carried out. The pendulum impact testing of Charpy specimens was performed at room temperature in compliance with national standards. The mechanical properties of the steel specimens were found to be considerably lower, and analogous to the properties values caused by hydrogen embrittlement.

Acoustic Emission Study of Corrosion Fatigue and Fatigue for API 5L X70 Gas Pipeline Steel

2011 ◽  
Vol 138-139 ◽  
pp. 635-639
Author(s):  
Z.H. Hanafi ◽  
Nordin Jamaludin ◽  
Shahrum Abdullah ◽  
M.F.M. Yusof ◽  
M.S.M. Zain
Keyword(s):  
Acoustic Emission ◽  
Fatigue Test ◽  
Corrosion Fatigue ◽  
Pipeline Steel ◽  
Petroleum Industry ◽  
Fatigue Behaviour ◽  
Pressure Vessels ◽  
Uniform Corrosion ◽  
Smooth Specimen ◽  
Steel Pipeline

Acoustic emission is a very important test among non-destructive tests, and it has been applied for the detection of failures in various types of equipment in the petroleum industry, such as pressure vessels, tanks and pipelines. In this study, the effect of pre-existing uniform corrosion on the corrosion fatigue specimen and smooth specimen on fatigue behaviour of API 5L X70 steel pipeline in long life range was investigated by using acoustic emission in fatigue test. The presence of pre-existing uniform corrosion specimen, produces by 4 month immersion in sulphuric acid, H2SO4 (concentration 0.2 ml H2SO4 in 5000 ml deionized water ). Fully reverse (R = -1) constant amplitude fatigue test were done in corrosion fatigue and smooth specimen in different stress amplitudes. It was found that, effect of pre-existing uniform corrosion significantly reduced the fatigue life of the steel pipeline. The correlations of accumulative AE counts for corrosion fatigue higher than fatigue test because of the mechanisms of possible AE sources due to corrosion.

Effects of Heat Treatment Process on Mechanical Properties of X70 Grade Pipeline Steel Bends

2015 ◽  
Vol 727-728 ◽  
pp. 322-326 ◽  
Author(s):  
Shi Lu Zhao ◽  
Zhen Zhang ◽  
Lian Chong Qu ◽  
Jun Zhang ◽  
Jian Ming Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Yield Strength ◽  
Thermal Insulation ◽  
Treatment Process ◽  
Pipeline Steel ◽  
Impact Testing ◽  
Air Cooling ◽  
Heat Treatment Process

Effects of heat treatment process of quenching and tempering under different temperature conditions on mechanical properties of X70 grade pipeline steel bends were studied. Brinell hardness, yield strength, tensile strength, elongation and impact absorbing energy of the bends were tested by using hardness tester, cupping machine and impact testing machine, respectively. It shows that the best heat treatment process of the X70 grade pipeline steel bends is quenching at 890 °Cand thermal insulation for 26 min then water cooling followed by tempering at 590 °C and thermal insulation for 60 min then air cooling. Furthermore, the resulting hardness, yield strength, tensile strength, yield ratio, elongation and impact absorbing energy reach HB230, 595 MPa, 725 MPa, 0.82, 28% and 300 J respectively, which has excellent comprehensive mechanical properties.

scholarly journals Sensitivity analysis of the GTN damage parameters at different temperature for dynamic fracture propagation in X70 pipeline steel using neural network

2021 ◽  
Vol 15 (58) ◽  
pp. 442-452
Author(s):  
Abdelmoumin Ouladbrahim ◽  
Idir Belaidi ◽  
Samir Khatir ◽  
Erica Magagnini ◽  
Roberto Capozucca ◽  
...  
Keyword(s):  
Neural Network ◽  
Pipeline Steel ◽  
Fem Analysis ◽  
Maximum Load ◽  
Impact Testing ◽  
The Neural Network ◽  
Different Temperatures ◽  
Satisfactory Approximation ◽  
Artificial Neural Network Ann ◽  
Growth Of Voids

In this paper, the initial and maximum load was studied using the Finite Element Modeling (FEM) analysis during impact testing (CVN) of pipeline X70 steel. The Gurson-Tvergaard-Needleman (GTN) constitutive model has been used to simulate the growth of voids during deformation of pipeline steel at different temperatures. FEM simulations results used to study the sensitivity of the initial and maximum load with GTN parameters values proposed and the variation of temperatures. Finally, the applied artificial neural network (ANN) is used to predict the initial and maximum load for a given set of damage parameters X70 steel at different temperatures, based on the results obtained, the neural network is able to provide a satisfactory approximation of the load initiation and load maximum in impact testing of X70 Steel.            

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

2012 ◽  
Author(s):  
Angelique N. Lasseigne ◽  
Kamalu M. Koenig ◽  
Joshua E. Jackson
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Real Time ◽  
Stress Measurement ◽  
Pipeline Steel ◽  
Mechanical Damage ◽  
Steel Pipeline ◽  
Stress Sensor ◽  
Integrity Assessment ◽  
Rapid Characterization

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.

Electrochemical and Tension Tests Behavior of API 5L X60 Pipeline Steel in a Simulated Soil Solution

2013 ◽  
Vol 755 ◽  
pp. 153-161 ◽  
Author(s):  
Luis M. Quej-Aké ◽  
Ricardo Galván-Martínez ◽  
Antonio Contreras-Cuevas
Keyword(s):  
Carbon Steel ◽  
Strain Rate ◽  
Soil Solution ◽  
Electrochemical Impedance ◽  
Pipeline Steel ◽  
Failure Process ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Tension Tests ◽  
Before And After

In this work electrochemical impedance spectroscopy (EIS) and slow strain rate tests (SSRT) were used for the evaluation of API 5L X60 carbon steel in contact with a simulated soil solution called NS4. EIS monitoring before and after performing the tension tests was carried out. SSRT were carried out in NS4 solution at room temperature to simulate dilute ground water that has been found associated with stress corrosion cracking (SCC) of low carbon steel pipelines. A strain rate of 1x10-6 sec-1 was used. According to the analysis of SSRT, the X60 pipeline steel is highly resistant to SCC. In order to perform the electrochemical test, two working electrodes were considered, a complete specimen, before the SSRT and a fractured specimen after the SSRT. The analyses of results show that the electrochemical response was different in each samples. The corrosion rate (CR) obtained by the two corrosion techniques revealed that the CR of the fractured specimen was higher than the CR of the complete specimen. This behavior is attributed to the fact that the fractured specimen present a high degree of tortuosity and this condition activate the corrosion process. In addition, according to the cathodic Tafel slope, the reduction reacction was influenced by a difusion process. A combine fracture type in SSRT was observed: ductil and brittle with a transgranular appearance. Some pits and internal cracks close to the fracture zone were observed. The failure process and mechanism of X60 steel in NS4 solution are controlled by dissolution and hydrogen embrittlement.

Microstructure and Toughness Properties of Subcritically, Intercritically and Supercritically Heat Affected Zones in X80 Pipeline Steel

2010 ◽  
Vol 154-155 ◽  
pp. 1850-1854 ◽  
Author(s):  
Sadegh Moeinifar
Keyword(s):  
Pipeline Steel ◽  
Charpy Impact ◽  
Initiation Site ◽  
Impact Testing ◽  
Peak Temperature ◽  
Coarse Grained ◽  
X80 Pipeline Steel ◽  
Brittle Phase ◽  
Charpy Impact Testing ◽  
Second Peak

The objective of this paper is to study the influence of second peak temperature during simulated welding on properties of the subcritically (S), intercritically (IC) and supercritically (SC) reheated coarse grained heat affected (CGHAZ) zones. This involved heating to a first peak temperature (TP1) of 1400 °C, then reheating to different second peak temperatures (TP2) of 700, 800 and 900 °C with a constant cooling rate of 3.75 °C/s. Toughness of the simulated reheated CGHAZ regions were assessed using Charpy impact testing at 0 and -50 °C. The blocky and connected M/A particles, along prior-austenite grain boundaries, act as a brittle phase for the initiation site of the brittle fracture. Charpy impact results indicated that IC CGHAZ had less absorbed energy with higher transition temperature and hardness.

Micromechanics of Hydrogen Transport and Embrittlement in Pipeline Steels

2006 ◽  
Author(s):  
Mohsen Dadfarnia ◽  
Petros Sofronis ◽  
Ian Robertson ◽  
Brian P. Somerday ◽  
Govindarajan Muralidharan ◽  
...  
Keyword(s):  
Steady State ◽  
Large Scale ◽  
Pipeline Steel ◽  
Hydrogen Effect ◽  
Hydrogen Transport ◽  
Material Microstructure ◽  
Central Production ◽  
Hydrogen Accumulation ◽  
Diffusion Of Hydrogen ◽  
Transient And Steady State

The technology of large scale hydrogen transmission from central production facilities to refueling stations and stationary power sites is at present undeveloped. Among the problems which confront the implementation of this technology is the deleterious effect of hydrogen on structural material properties, in particular at gas pressure of 1000 psi which is the desirable transmission pressure suggested by economic studies for efficient transport. To understand the mechanisms of hydrogen embrittlement our approach integrates mechanical property testing, TEM observations, and finite element modeling. In this work a hydrogen transport methodology for the calculation of hydrogen accumulation ahead of a crack tip in a pipeline steel is outlined. The approach accounts for stress-driven transient diffusion of hydrogen and trapping at microstructural defects whose density evolves dynamically with deformation. The results are analyzed to correlate the level of load in terms of the applied stress intensity factor with the time after which hydrogen transport takes place under steady state conditions. The transient and steady state hydrogen concentration profiles are used to assess the hydrogen effect on the mechanisms of fracture as they depend on material microstructure.

Effect of nanoclay addition on mechanical and thermal behavior of vinyl ester based nanocomposites obtained by casting

2014 ◽  
Vol 11 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Harun Sepet ◽  
Necmettin Tarakçıoğlu
Keyword(s):  
Vinyl Ester ◽  
Testing Machine ◽  
Impact Resistance ◽  
Xrd Analysis ◽  
Impact Testing ◽  
Homogeneous Distribution ◽  
Mechanical And Thermal Properties ◽  
The Matrix ◽  
Nanoclay Content ◽  
Dsc Curves

This paper presents the experimental study of mechanical and thermal properties of organically modified montmorillonite clay (Nanoclay) (0, 1, 2, 3, 4 and 5 wt.%) in the vinyl ester matrix by ultrasonic stirrer. The changes in mechanical properties are investigated by using tensile and impact testing machine. It was found that the addition of nanoclay particles significantly improved tensile properties of pure vinyl ester, but impact properties of pure vinyl ester were affected negatively with the nanoclay content in the nanocomposite. It was found that the absorbed energy and impact resistance of the nanocomposites decreased with increasing the nanoclay content. DSC curves showed the glass transition temperature change in the nanoclay reinforced vinyl ester nanocomposites as compared to the pure vinyl ester. XRD analysis was performed to identify the structure of nanocomposites. SEM results showed the change in fracture surface morphology of nanoclay reinforced vinyl ester nanocomposite. Also, homogeneous distribution of nanoclays in the matrix was showed by SEM micrographs. This observation helped in identifying the morphology of the nanocaly in the vinyl ester matrix.

Effect of Cold-Wire Addition in the TSAW Process on Microstructure and Mechanical Properties of the HAZ of X70 Microalloyed Pipeline Steel

2016 ◽  
Author(s):  
Mohsen Mohammadijoo ◽  
Stephen Kenny ◽  
Laurie Collins ◽  
Hani Henein ◽  
Douglas G. Ivey
Keyword(s):  
Mechanical Properties ◽  
Heat Affected Zone ◽  
Pipeline Steel ◽  
Microstructural Analysis ◽  
Research Work ◽  
High Heat ◽  
Impact Testing ◽  
Microalloyed Steels ◽  
Cold Wire ◽  
High Heat Input

Microalloyed steels can achieve a good combination of strength and toughness through appropriate alloy design and thermomechanical controlled processing (TMCP). However, the mechanical properties can deteriorate as a result of the high heat input and thermal cycles that the steel experiences during welding. It is generally accepted that the portion of the heat affected zone (HAZ) adjacent to the fusion line, i.e., the coarse grain heat affected zone (CGHAZ), which is characterized by coarse grains and martensite-austenite (M-A) constituents, is the region with poorer toughness relative to the rest of the steel. In the present research work, modification to the conventional tandem submerged arc welding (TSAW) process is carried out by the addition of a cold wire during welding (CWTSAW), which induces changes to the geometry and properties of the weld joint. Microstructural analysis, mechanical property investigation and geometry analysis indicate overall improvement in the weld and the HAZ properties after cold wire addition. These improvements are explained in terms of an increase in the deposition rate and a decrease in the amount of heat introduced to the weldment. An X70 microalloyed steel was welded using both TSAW and CWTSAW processes. Charpy-V-notch impact testing and microhardness testing showed improvement in the HAZ mechanical properties for CWTSAW samples relative to TSAW samples. Microstructural analysis, using both optical microscopy and scanning electron microscopy (SEM), indicated the formation of finer prior austenite grains (PAG) and less M-A constituent within the CGHAZ of the CWTSAW samples. These improvements are due to lower actual heat introduced to the weldment and a relatively faster cooling rate.

Microstructure and Mechanical Properties of Joints of X100 Line Pipe by Submerged Arc Welding

2013 ◽  
Vol 310 ◽  
pp. 139-144 ◽  
Author(s):  
Min Zhang ◽  
Liang Yang
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Shear Fracture ◽  
Pipeline Steel ◽  
Testing Machine ◽  
Fracture Morphology ◽  
Impact Testing ◽  
Granular Bainite ◽  
Line Pipe ◽  
The Impact

The microstructure, mechanical properties, fracture morphology and crystal texture of pipeline steel X100 welded joints were investigated using optical electron microscope, scanning electron microscope, tensile and impact testing machine. The results show that, the texture of X100 line pipe mainly consists of acicular ferrite and granular bainite in weld zones, the microstructure of HAZ is coarser, which lead to softening and embrittlement. The fusion line is clear between outer weld and inner weld. The tensile strength of welded joint gets to 803 MPa, which is about 94.81% of the base materials. The impact energy at -10°C is more than 120J, and the average of percent shear fracture appearance at -10°C is up to 85%, is ductile fractures.

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