Texture, local misorientation, grain boundary and recrystallization fraction in pipeline steels related to hydrogen induced cracking

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.

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Effect of effective grain size and grain boundary of large misorientation on upper shelf energy in pipeline steels

Journal of Wuhan University of Technology-Mater Sci Ed ◽

10.1007/s11595-016-1417-5 ◽

2016 ◽

Vol 31 (3) ◽

pp. 606-610 ◽

Cited By ~ 3

Author(s):

Xiaoli Zhang ◽

Zhiqiang Jiang ◽

Shixian Li ◽

Jiwei Fan

Keyword(s):

Grain Size ◽

Grain Boundary ◽

Shelf Energy ◽

Pipeline Steels ◽

Effective Grain Size

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Stress Corrosion Cracks in Pipeline Steels

10.32545/encyclopedia201906.0002.v1 ◽

2019 ◽

Author(s):

Mohammad Ali Mohtadi Bonab

Keyword(s):

Grain Boundary ◽

Crack Propagation ◽

Grain Boundaries ◽

Stress Corrosion ◽

Coincidence Site Lattice ◽

Rolling Plane ◽

Pipeline Steels ◽

Factors Affecting ◽

Boundary Character ◽

Grain Boundary Character

The demand for pipeline steels has increased in the last several decades since they were able to provide an immune and economical way to carry oil and natural gas over long distances. There are two important damage modes in pipeline steels including stress corrosion cracking (SCC) and hydrogen induced cracking (HIC). The SCC cracks are those cracks which are induced due to the combined effects of a corrosive environment and sustained tensile stress. The present review article is an attempt to highlight important factors affecting the SCC in pipeline steels. Based on a literature survey, it is concluded that many factors, such as microstructure of steel, residual stresses, chemical Composition of steel, applied load, alternating current (AC) current and texture, and grain boundary character affect the SCC crack initiation and propagation in pipeline steels. It is also found that crystallographic texture plays a key role in crack propagation. Grain boundaries associated with {111}//rolling plane, {110}//rolling plane, coincidence site lattice boundaries and low angle grain boundaries are recognized as crack resistant paths while grains with high angle grain boundaries provide easy path for the SCC intergranular crack propagation. Finally, the SCC resistance in pipeline steels is improved by modifying the microstructure of steel or controlling the texture and grain boundary character.

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Hydrogen Induced Cracking in Pipeline Steels

CORROSION ◽

10.5006/1.3593931 ◽

1984 ◽

Vol 40 (7) ◽

pp. 330-336 ◽

Cited By ~ 29

Author(s):

A. Brown ◽

C. L. Jones

Keyword(s):

Pipeline Steels ◽

Hydrogen Induced Cracking

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Model of Parameters Controlling Resistance of Pipeline Steels to Hydrogen-Induced Cracking

CORROSION ◽

10.5006/1056 ◽

2014 ◽

Vol 70 (1) ◽

pp. 87-94 ◽

Cited By ~ 3

Author(s):

A. Traidia ◽

A.M. El-Sherik ◽

S. Duval ◽

G. Lubineau ◽

J. El-Yagoubi

Keyword(s):

Pipeline Steels ◽

Hydrogen Induced Cracking

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The Micro Structural Characteristic Parameters of High Grade Pipeline Steel and its Mechanical Properties

Volume 3: Materials and Joining; Pipeline Automation and Measurement; Risk and Reliability, Parts A and B ◽

10.1115/ipc2006-10256 ◽

2006 ◽

Cited By ~ 2

Author(s):

Xiaoli Zhang ◽

Chuanjing Zhuang ◽

Lingkang Ji ◽

Yaorong Feng ◽

Wenzhen Zhao ◽

...

Keyword(s):

Mechanical Properties ◽

Grain Boundary ◽

Grain Boundaries ◽

Pipeline Steel ◽

Structural Parameters ◽

Large Angle ◽

Lower Bainite ◽

Granular Bainite ◽

High Grade ◽

Pipeline Steels

The microstructure of high grade pipeline steels, including X65, X70, X80, X100, were studied by SEM and EBSD, respectively. It was found that the microstructures of high grade pipeline steels were composed of lower bainite, granular bainite and acicular ferrite. The phases of kinds of pipeline steels were composed of Fe3C, retained austenite and ferrite. And their percentage content, grain size and its distribution were studied respectively also. These micro structural parameters were correlated to the mechanical properties of kinds of pipeline steels. Furthermore, all kinds of angles of grain boundaries were studied, and the relationship between the angles of grain boundaries and mechanical properties was obtained. It was shown that as the improving of the steel grade, the grain boundary including small angle and large angle increased. And only when grain boundary was greater than 15 degree, it was effective to the toughness behavior.

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