The extension of hydrogen blister-crack array in linepipe steels

Iino, Makio

doi:10.1007/bf02661940

Cited by 47 publications

(15 citation statements)

References 4 publications

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“…As can be seen from Figure 11, maximum stresses are located at the crack tips. It indicates the stresses interacting at this region, which align with the development of cracking due to the interconnection of perpendicular cracks [11]. The above situation agrees with the fracture mechanics postulate, the direction of cracking corresponds to the direction of the main stresses.…”

Section: /31supporting

confidence: 83%

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Analysis of 3D Planar Laminations in a Welded Section of API 5L X52 Applying the Finite Element Method

et al. 2018

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Abstract:The mechanical behavior of API 5L X52 steel with planar type laminations was studied in the present work. Planar laminations were proposed in the base metal (BM), heat affected zone (HAZ) and welding bead (WB). Three-dimensional finite element (FE) models, kinematic hardening and mechanical properties for BM, HAZ, and WB were activated in the finite element program. The results showed that crack propagation corresponds to the direction of the main stress. For a crack length (2a) of 10.01 mm, crack propagation may occur at the right crack tip towards the outer wall of the BM. For 2a of 15.12 mm, crack propagation was located on the right crack tip and propagates to the inner wall. For 2a of 17.12 mm, crack propagation was observed at the left crack tip and propagates to the outer wall in the BM. The results achieved by FEM agree when compared with real laminations in API 5L pipelines.

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Section: /31supporting

confidence: 83%

“…This cracking growth is in the same plane, parallel to the wall of the pipeline [10]. According to Iino [11], a stress state in the vicinity of the crack tip is significantly influenced by the hoop external stress in API 5L pipelines.…”

Section: /31mentioning

confidence: 99%

Analysis of 3D Planar Laminations in a Welded Section of API 5L X52 Applying the Finite Element Method

et al. 2018

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“…Many models [5,7,23] of hydrogen-induced cracking in steel suggest that the hydrogen atoms diffuse to low free energy locations, for example, the interface of matrix and inclusions such as manganese sulfides (MnS). At these locations, the hydrogen atoms can combine to form hydrogen molecules that will exert a pressure on the surrounding steel, resulting in a crack.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3] The hydrogen-induced blisters in medium strength steel during cathodic charging or in contact with wet hydrogen sulphide (H 2 S) has also been widely studied. [4][5][6] The internal fissures are believed to be induced by combination of atomic hydrogen at high concentration resulting in molecular hydrogen formation. [7,8] Furthermore, hydrogen blister or crack appears in many other materials in the absence of external stress if the hydrogen concentration is high enough.…”

Section: Introductionmentioning

confidence: 99%

A Nucleation Mechanism of Hydrogen Blister in Metals and Alloys

Ren

Zhou

Shan

et al. 2007

Metall Mater Trans A

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The nucleation process of hydrogen blister in metals was investigated through experiments and the mechanism was discussed. Small hydrogen blister in charged Ni-P amorphous coating and steel was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The thermodynamics and kinetics of hydrogen and vacancies in metals are analyzed. Further, an approach of the nucleation mechanism of hydrogen blister is proposed as follows. Atomic hydrogen can induce superabundant vacancies in metals. The superabundant vacancies and hydrogen aggregate into a hydrogen-vacancy cluster (small cavity). The hydrogen atoms in the hydrogen-vacancy cluster become hydrogen molecules that can stabilize the cluster. And the hydrogen blister nucleates. The pressure in the small cavity increases as the hydrogen atoms enter the cavity. The cluster, that is, the hydrogen blister nucleus, grows through vacancies diffusing into it under the action of cluster-hydrogen binding energy and hydrogen pressure. When the blister nucleus grows to a critical size C cr cracks will initiate from the wall of the cavity due to the internal hydrogen pressure.

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“…The mechanisms of the formation of the blisters or cracks have been discussed widely [4][5][6] . Most of the mechanisms suggest that hydrogen atoms combine into hydrogen molecules in the interface of second phase and matrix, and the hydrogen molecules produce high hydrogen pressure to induce microcracks.…”

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confidence: 99%

The mechanism of nucleation of hydrogen blister in metals

et al. 2007

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The nucleating, growing and cracking of hydrogen blister have been investigated experimentally and theoretically. The results show that atomic hydrogen induces superabundant vacancies in metals. The superabundant vacancies and hydrogen aggregate into a hydrogen-vacancy cluster (microcavity). The hydrogen atoms in the microcavity become hydrogen molecules which can stabilize the cluster. And the hydrogen blister nucleates. With the entry of vacancies and hydrogen atoms, the blister nucleus grows and the pressure in the cavity increases. When the stress induced by hydrogen pressure on the blister is up to the cohesive strength, cracks will initiate from the wall of the blister.hydrogen blister, vacancy cluster, nucleation, cracking Hydrogen blister or hydrogen crack appears in many materials in the absence of external stress when the hydrogen concentration is high enough [1][2][3] . The mechanisms of the formation of the blisters or cracks have been discussed widely [4][5][6] . Most of the mechanisms suggest that hydrogen atoms combine into hydrogen molecules in the interface of second phase and matrix, and the hydrogen molecules produce high hydrogen pressure to induce microcracks. The propagation and connection of the microcracks induce the formation of the hydrogen blisters or hydrogen cracks. Hydrogen atoms cannot combine into hydrogen molecules which induce hydrogen pressure when there is no interspace to accommodate the hydrogen atoms. Hydrogen atoms can be trapped in pre-existing microvoids or microcracks in a material and become hydrogen molecules. The microvoids or microcracks containing hydrogen molecules become hydrogen blisters (a lacuna full of H 2 in the interior of materials also is called a hydrogen blister in this paper). For some materials with good plasticity and even single crystalline metals, there are neither microvoids nor microcracks in them, but hydrogen blisters or hydrogen cracks can appear if they are charged. How are the lacunas containing H 2 (hydrogen blister) produced?There are abundant supersaturated vacancies in metals quenched from high temperature. The supersaturated vacancies can aggregate into vacancy clusters (microlacuna) and then collapse into dislocation loops or stacking fault tetrahedral [7] . If the supersaturated vacancies can be induced by hydrogen and can aggregate into vacancy clusters to accommodate molecular hydrogen, the hydrogen blisters will be formed during charging. This work is an attempt to confirm this hypothesis through experiments and theoretical analysis. Here a mechanism describing the nucleating, growing and cracking of hydrogen blister in metals is presented.

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The extension of hydrogen blister-crack array in linepipe steels

Cited by 47 publications

References 4 publications

Analysis of 3D Planar Laminations in a Welded Section of API 5L X52 Applying the Finite Element Method

Analysis of 3D Planar Laminations in a Welded Section of API 5L X52 Applying the Finite Element Method

A Nucleation Mechanism of Hydrogen Blister in Metals and Alloys

The mechanism of nucleation of hydrogen blister in metals

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