Strain-aging-assisted localized corrosion of a mill-scaled X-65 pipeline steel

CORROSION ◽  
10.5006/3721 ◽  
2021 ◽  
Author(s):  
Shidong Wang ◽  
Lyndon Lamborn ◽  
Karina Chevil ◽  
Erwin Gamboa ◽  
Weixing Chen
Keyword(s):  
Strain Aging ◽  
Unsolved Problem ◽  
Pipeline Steel ◽  
Galvanic Corrosion ◽  
Steel Substrate ◽  
Localized Corrosion ◽  
Oxide Scales ◽  
Pipeline Steels ◽  
Stress Cycles ◽  
Vital Factor

This investigation was designed to study whether strain aging could assist localized corrosion of pipeline steels under realistic conditions, which is an unsolved problem in the evaluation of strain-aging-induced stress corrosion cracking of pipeline steels in the field. It was found that the corrosion severity was significantly aggravated after strain aging because of the increase in yield strength and the transformation of oxide scales on the steel surface. These variations caused by strain aging lead to lesser exfoliation and longer life of the oxide scales under cyclic loading in air and during subsequent corrosion exposure, which enhances the galvanic corrosion between oxide scales and the steel substrate. The composition of oxide scales, mechanical properties of steels, and magnitude of the stress cycles, which could all impact localized corrosion, were studied. The findings of this investigation suggest that the severe localized corrosion leading to crack initiation is a vital factor for the higher SCC susceptibility of pipeline steels associated with strain aging, in addition to the enhanced hydrogen embrittlement as usually believed.

Corrosion Resistance of Dissimilar GTA Welds of Pipeline Steel and Super Duplex Stainless Steels in Synthetic Brine

CORROSION ◽  
10.5006/3746 ◽  
2021 ◽  
Author(s):  
Víctor Vargas ◽  
Apolinar Albiter-Hernandez ◽  
Marco Dominguez Aguilar ◽  
Gerardo Altamirano-Guerrero ◽  
Cuahtemoc Maldonado
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Pipeline Steel ◽  
Localized Corrosion ◽  
Nickel Wire ◽  
Super Duplex Stainless Steel ◽  
Gas Tungsten Arc ◽  
Dissimilar Welds ◽  
Super Duplex Stainless Steels

The effect of weld passes and single V grove designs, on the corrosion resistance of dissimilar welds of a low alloy steel and a super-duplex stainless steel, was studied in synthetic brine. Welds were manufactured in argon by gas tungsten arc (GTA) technique and joined by a high nickel wire of super-duplex stainless steel. Samples of weld regions were characterized by composition scans, electrochemical measurements, micro-hardness and scanning electron microscopy. In X52/ER2594, a transition region (TR) of grain boundaries type II and a band of martensite were formed. The base metal of X52 underwent the highest corrosion rate and localized corrosion occurred in the heat affected zone. Interface ER2594/25Cr7Ni and 25Cr7Ni showed the presence of pitting near intermetallics.

scholarly journals Strain Aging Behavior of Microalloyed Low Carbon Seamless Pipeline Steel

2016 ◽  
Vol 56 (1) ◽  
pp. 126-131 ◽  
Author(s):  
Qianlin Wu ◽  
Zhonghua Zhang ◽  
Yaoheng Liu
Keyword(s):  
Strain Aging ◽  
Pipeline Steel ◽  
Low Carbon ◽  
Aging Behavior

scholarly journals The Pitting Susceptibility Investigation of Passive Films Formed on X70, X80, and X100 Pipeline Steels by Electrochemical Noise and Mott-Schottky Measurements

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Yang Zhao ◽  
Ping Liang ◽  
Yanhua Shi ◽  
Yunxia Zhang ◽  
Tao Yang
Keyword(s):  
Distribution Function ◽  
Electrochemical Noise ◽  
Pipeline Steel ◽  
Stochastic Theory ◽  
Gumbel Distribution ◽  
Passive Films ◽  
Initiation Rate ◽  
Pipeline Steels ◽  
X100 Pipeline Steel ◽  
Pit Initiation

The pitting susceptibility of passive films formed on X70, X80, and X100 pipeline steels was investigated by means of electrochemical noise (EN) and Mott-Schottky measurements. The EN results were analyzed according to the shot-noise theory and stochastic theory. Pit initiation process was analyzed quantitatively using the Weibull distribution function. Pit growth process was simulated by Gumbel distribution function. The experimental results of Mott-Schottky plots showed that the passive films formed on the three pipeline steels displayed an n-type semiconductor character, and the passive film for X100 pipeline steel has the lowest donor density (ND) among the three passive films. The EN results demonstrated that X100 pipeline steel had the lowest pit initiation rate and pit growth probability, which implied that the X100 pipeline steel had the lowest pitting susceptibility.

scholarly journals Galvanic Corrosion Due to a Heterogeneous Sulfate Reducing Bacteria Biofilm

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1116
Author(s):  
Hongwei Liu ◽  
Haixian Liu ◽  
Yuxuan Zhang
Keyword(s):  
Galvanic Corrosion ◽  
Steel Corrosion ◽  
Localized Corrosion ◽  
Cathodic Reaction ◽  
Anodic Reaction ◽  
Sulfate Reducing ◽  
Corrosion Effect ◽  
Desulfotomaculum Nigrificans ◽  
Corrosion Of Steel ◽  
Reducing Bacteria

In this work, the galvanic corrosion behavior of sulfate reducing Desulfotomaculum nigrificans biofilm-covered and uncovered carbon steel was investigated using various electrochemical measurements. The results showed that the bare specimen in the abiotic solution functions as the anode; whereas the biofilm-covered specimen in the SRB-containing solution functions as the cathode after two electrodes being coupled. The anodic reaction of specimen in the biotic solution containing SRB was inhibited; whereas the cathodic reaction was considerably promoted after coupling. Hence, localized corrosion of specimen in the abiotic solution was observed due to the galvanic corrosion effect. SRB could still accelerate steel corrosion even after coupling, but the results indicate that the contribution of SRB to steel corrosion decreased. The localized corrosion of steel in the SRB-containing environments not only involved the SRB biofilm, but also a galvanic corrosion effect. The flow of electrons from the anodic dissolution of Fe in the abiotic solution to the SRB cells of cathodic area decreased the acceptance capacity of electrons by SRB from steel beneath biofilm. As a result, the steel corrosion beneath SRB biofilm decreased after coupling.

Guidelines for Production of API Pipelines Steels Suitable for Hydrogen Induced Cracking (HIC) Service Applications

2010 ◽  
Author(s):  
Douglas G. Stalheim ◽  
Bernhard Hoh
Keyword(s):  
Mechanical Property ◽  
Natural Gas ◽  
Pipeline Steel ◽  
Steel Production ◽  
The Other ◽  
Corrosion Mechanism ◽  
Pipeline Steels ◽  
Hydrogen Induced Cracking ◽  
Oil And Natural Gas ◽  
Sour Service

Worldwide oil and natural gas reserves can be classified as either sweet or sour service. The sour service classified oil and natural gas reserves contain some level of H2S making the product flowing through a steel pipeline corrosive. Due to this, the majority of the oil and natural gas reserves that have been drilled are of the sweet service nature. However as demand continues and supplies change, many of the remaining oil and natural gas reserves contain the H2S component and are of a sour service nature. These oil and natural gas reserves containing the H2S component through a corrosion mechanism will allow for diatomic hydrogen — in the presence of moisture — to disseminate to monatomic hydrogen and diffuse into the pipeline steel microstructure. Depending on the microstructure and level of cleanliness the monatomic hydrogen can become trapped at areas of high residual stress, recollect to diatomic hydrogen and creating partial pressures that exceed the tensile strength of the steel resulting in cracking. Therefore transmission pipelines are being built to transport sour service oil or natural gas requires steels with hydrogen induced cracking (HIC) resistance. Alloy designs, steel making processing, continuous casting, plate or strip rolling, pipe forming, and last not least corrosion testing are all key components in producing pipeline steels that are resistant to HIC applications and meeting the NACE TM0284 specifications. However, producing steels that have good HIC performance do not necessarily meet other mechanical property requirements such as strength and YT ratios. Balance has to be achieved to meet not only the HIC requirements but the other required mechanical properties. Mastering this complex HIC process poses a serious challenge to pipe producers and their primary material suppliers. The capability of producing HIC steel grades according to critical specifications and/or standards clearly distinguishes excellent steel producers from good steel makers. This paper will discuss the basics of the hydrogen induced cracking phenomenon, the requirements of the NACE TM0284 specification and give guidelines for steel production of API pipeline steels that not only can meet the specification requirements the NACE testing but also fulfill the other mechanical property requirements.

Experimental Investigation of Ductile Tearing Properties for API X70 and X80 Pipeline Steels

2005 ◽  
Author(s):  
Mauri´cio Carvalho Silva ◽  
Eduardo Hippert ◽  
Claudio Ruggieri
Keyword(s):  
Pipeline Steel ◽  
Standard Procedure ◽  
Tensile Tests ◽  
Compact Tension ◽  
Propagation Path ◽  
Pipeline Steels ◽  
Ductile Tearing ◽  
Resistance Curves ◽  
Unloading Compliance ◽  
Fracture Specimens

This work presents an investigation of the ductile tearing properties for API 5L X70 and X80 pipeline steels using experimentally measured crack growth resistance curves (J-R curves). Testing of the pipeline steels employed compact tension (C(T)) fracture specimens to determine the J-R curves based upon the unloading compliance method using a single specimen technique in accordance with the ASTM E1820 standard procedure. Conventional tensile tests and Charpy V-Notch tests were also performed to determine the mechanical and impact properties for the tested materials. Severe splitting running parallel with the crack propagation path with varied lengths was observed in all tested fracture specimens, particularly for the API X80 material. The occurrence of splits makes the determination of JIc and resistance curves more difficult, as delamination of interfaces positioned normal to the crack front decreases the effective thickness of the test piece, inducing plane stress conditions deep inside the specimen. This experimental characterization provides additional toughness and mechanical data against which the general behavior of X70 and X80 class pipeline steel can be compared.

scholarly journals Effects of LaAlO3 and La2O2S inclusions on the initialization of localized corrosion of pipeline steels in NaCl solution

2020 ◽  
Vol 177 ◽  
pp. 151-156 ◽  
Author(s):  
Yanhui Hou ◽  
Gang Xiong ◽  
Linli Liu ◽  
Guangqiang Li ◽  
Nele Moelans ◽  
...  
Keyword(s):  
Localized Corrosion ◽  
Nacl Solution ◽  
Pipeline Steels
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