scholarly journals Stress Corrosion Cracks in Pipeline Steels

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.

scholarly journals Effects of Different Parameters on Initiation and Propagation of Stress Corrosion Cracks in Pipeline Steels: A Review

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 590 ◽  
Author(s):  
M.A. Mohtadi-Bonab
Keyword(s):  
Grain Boundary ◽  
Crack Propagation ◽  
Grain Boundaries ◽  
Stress Corrosion ◽  
Coincidence Site Lattice ◽  
Rolling Plane ◽  
Pipeline Steels ◽  
Boundary Character ◽  
Grain Boundary Character ◽  
Initiation And Propagation

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.

A Microtexture-Microstructure Model to Simulate Intergranular Stress Corrosion Crack Propagation in Pipeline Steel

2010 ◽  
Author(s):  
M. A. Arafin ◽  
J. A. Szpunar
Keyword(s):  
Grain Boundary ◽  
Crack Propagation ◽  
Stress Corrosion ◽  
Pipeline Steel ◽  
Monte Carlo Model ◽  
Distribution Functions ◽  
Electron Backscattered Diffraction ◽  
Intergranular Stress Corrosion ◽  
Boundary Character ◽  
Grain Boundary Character

Electron backscattered diffraction (EBSD) investigations were carried out to obtain the microtexture, grain boundary character, and physical microstructural parameters, such as the grain size and grain shape distributions, of API X65 pipeline steel that experienced extensive intergranular stress corrosion cracking (IGSCC). The orientation distribution functions (ODF) and the grain boundary character distributions (GBCD) of the cracked and crack-arrest microstructures were obtained from the EBSD data of the corresponding regions. First, a Voronoi algorithm based microstructure reconstruction model has been utilized to generate model microstructure that resembles the experimentally observed ones. Subsequently, a Markov Chain–Monte Carlo model, coupled with the grain boundary character and orientation dependent vulnerability statistics, has been employed to simulate the crack propagation behavior. The simulation results are in good agreement with the experimental observations.

Metal precipitation at grain boundaries in silicon: Dependence on grain boundary character and dislocation decoration

2006 ◽  
Vol 89 (4) ◽  
pp. 042102 ◽  
Author(s):  
T. Buonassisi ◽  
A. A. Istratov ◽  
M. D. Pickett ◽  
M. A. Marcus ◽  
T. F. Ciszek ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Character ◽  
Grain Boundary Character ◽  
Metal Precipitation

Application of Microdiffraction in Sem for Assessing Intrinsic Materials Susceptibility to Intergranular Corrosion and Stress Corrosion Cracking

1997 ◽  
Vol 3 (S2) ◽  
pp. 573-574
Author(s):  
G. Palumbo ◽  
E.M. Lehockey ◽  
P. Lin
Keyword(s):  
Grain Boundary ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Service Failure ◽  
Coincidence Site Lattice ◽  
Corrosion Cracking ◽  
Polycrystalline Materials ◽  
Materials Synthesis ◽  
Intergranular Cracking ◽  
Grain Boundary Character

Intergranular degradation processes (e.g., corrosion, stress corrosion cracking) are a frequent cause of premature and unpredictable service failure of engineering components. Since these processes cause component failure via propagation through the intercrystalline network, they are strongly dependent upon the distribution of specific grain boundary structures in the material. Previous studies have shown that grain boundaries crystallographically described by low Σ (Σ≤29) Coincidence Site Lattice (CSL) relationships can often selectively display a high resistance (and often immunity) to corrosion and fracture. Recent advances in automated microdiffraction techniques (e.g., EBSP) in SEM have now made it possible to readily evaluate grain boundary character distributions in conventional polycrystalline materials. by utilizing this technique, and by formulating and applying simple stochastic models for the propagation of intergranular cracking and corrosion processes, the opportunity now exists for (1) improved component lifetime prediction, and (2) the optimization of materials synthesis techniques to yield intergranular-degradation resistant microstructures.

SEM-ECP Analysis of Grain-Boundary Character Distribution in Polycrystalline Materials

1996 ◽  
Vol 54 ◽  
pp. 354-355
Author(s):  
Tadao Watanabe
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Migration ◽  
Polycrystalline Materials ◽  
Grain Boundary Character Distribution ◽  
Boundary Character ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Boundary Character Distribution

As demonstrated early 1980’s (1), the scanning electron rnicrocopy-electron channelling pattern (SEM-ECP) technique is very powerful in determination of orientation of individual grains and the character of grain boundaries in polycrystalline materials. Figure 1(a) and (b) show SEM and ECP images of a grain boundary in polycrystal line iron-6.5 mass % silicon ribbon produced by rapid solidification and subsequent annealing. We can intuitively recognize from the SEM-ECP image that the character of the boundary is of <100> tilt type with about 7° misorientation angle. This kind of direct observation is very useful for a study of grain boundary migration and grain growth.This paper discusses advantages of the SEM-ECP technique for the precise determination of the character of grain boundary and for statistical analysis of grain boundaries to bridge roles of individual grain boundaries and bulk properties in a polycrystal. The new microstructural parameter associated with grin boundary termed “grain boundary character distribution (GBCD)” which was introduced by the present author (2,3) and has been utilized in designing and engineering grain boundaries in order to produce desirable and/or high bulk performance in polycrystalline materials (4,5). GBCD describes the type and the frequency of different types of grain boundaries, ie. random general boundaries and special boundaries like low-angle boundaries and low Σ coincidence boundaries.

Grain Boundary Engineering: Progress and Challenges

2007 ◽  
Vol 539-543 ◽  
pp. 3389-3394 ◽  
Author(s):  
Wei Guo Wang
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Electron Backscatter Diffraction ◽  
Coincidence Site Lattice ◽  
Grain Boundary Character Distribution ◽  
Grain Boundary Engineering ◽  
Special Boundaries ◽  
Grain Boundary Character ◽  
Proposed Model ◽  
Backscatter Diffraction

The progress of grain boundary engineering (GBE) is overviewed and the challenges for further investigations emphasized. It points out that, the electron backscatter diffraction (EBSD) reconstruction of grain boundaries, which gives the information of connectivity interruption of general high angle boundaries (HABs), is more significant than purely pursuing high frequency of so-called special boundaries. The criterion for the optimization of grain boundary character distribution (GBCD) needs to be established. The energy spectrum and the degradation susceptibility of grain boundaries of various characters including HABs and low Σ（Σ≤29） coincidence site lattice (CSL) needs to be studied and ascertained. And finally, the newly proposed model of non-coherent Σ3 interactions for GBCD optimization are discussed.

The Potential of HAZ Property Improvement through Control of Grain Boundary Character in a Wrought Ni-Based Superalloy

2010 ◽  
Vol 654-656 ◽  
pp. 488-491 ◽  
Author(s):  
Hyun Uk Hong ◽  
In Soo Kim ◽  
Baig Gyu Choi ◽  
Hi Won Jeong ◽  
Seong Moon Seo ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Solution Treatment ◽  
Crystallographic Analysis ◽  
Treatment Temperature ◽  
Solution Treatment Temperature ◽  
Slow Cooling ◽  
Grain Coarsening ◽  
Boundary Character ◽  
Grain Boundary Character

The effects of grain boundary serration on grain coarsening and liquation behavior in simulated weld heat-affected-zone (HAZ) of a wrought Ni-based superalloy Alloy 263 have been investigated. Recently, the present authors have found that grain boundary serration occurs in the absence of adjacent coarse γ' particles or M23C6 carbides when a specimen is direct-aged with a combination of slow cooling from solution treatment temperature to aging temperature. This serration leads to a change in grain boundary character as special boundary based on the crystallographic analysis demonstrating that the grain boundaries tend to serrate to have specific segments approaching to one {111} low-index plane at a boundary. The present study was initiated to investigate the interdependence of the serration and HAZ property with a consideration of this serration as a potential for the use of a damage-tolerant microstructure. It was found that the serrated grain boundaries suppress effectively grain coarsening, and are highly resistant to liquation cracking in HAZ due to their lower tendency to be wetted and penetrated by the liquid phase. These results reflect closely a significant decrease in interfacial energy as well as grain boundary configuration by the serration.

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