Critical issues in hydrogen assisted cracking of structural alloys

Gangloff, Richard P.

doi:10.1016/b978-008044635-6.50015-7

Cited by 57 publications

(48 citation statements)

References 30 publications

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“…Les études expérimentales de ces phénomènes sont nombreuses. On pourra se reporter aux revues publiées sur ces phénoménologies [1][2][3]. Si la description des manifestations macroscopiques est bien établie, on ne dispose pourtant pas aujourd'hui d'un cadre général permettant de quantifier et prédire ces effets.…”

Section: Introductionunclassified

Couplage hydrogène - plasticité dans les matériaux cubiques à faces centrées

Delafosse

2009

PlastOx 2007 - Mécanismes Et Mécanique Des Interactions Plasticité - Environnement

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Résumé. Les interactions entre hydrogène en solution solide et plasticité sont étudiées et modélisées du point de vue de la métallurgie physique et de la théorie élastique des défauts discrets dans les cristaux cubiques à faces centrées. Des essais de vieillissement statique permettent d'évaluer quantitativement l'interaction élastique entre dislocations mobiles et atmosphères de solutés dans le nickel et dans un alliage binaire nickel-chrome. Les principes du couplage élastique entre solutés et dislocations sont rappelés et la notion d'indice d'écrantage des interactions de paires est introduite. Cette notion permet d'évaluer les effets de l'hydrogène sur l'énergie de ligne des dislocations, la tension de ligne, la contrainte critique d'activation de sources de Franck-Read, la stabilité des jonctions et la distance de séparation entre partielles qui gouverne le glissement dévié. Des essais de traction sur des monocristaux orientés pour le glissement simple permet d'évaluer les effets macroscopiques du couplage hydrogène -plasticité. L'observation par microscopie électronique à transmission des structures de déformation permet de mettre en évidence le glissement dévié comme étant le mécanisme élémentaire de plasticité le plus fortement affecté par la présence d'hydrogène en solution. Ces résultats sont discutés sous l'angle des mécanismes de rupture par effets de l'hydrogène.

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Section: Introductionunclassified

Couplage hydrogène - plasticité dans les matériaux cubiques à faces centrées

Delafosse

2009

PlastOx 2007 - Mécanismes Et Mécanique Des Interactions Plasticité - Environnement

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“…As the amount of hydrogen absorbed increased by a decrease in pH or an increasing cathodic current, the time to failure at constant load (Snape, 1967) and the performance in an SSRT (Kawashima et al, 1976) decreased accordingly. Likewise, as the diffusible hydrogen content increases, the threshold stress intensity for hydrogen cracking decreases (Gangloff, 2003;Gerberich & Chen, 1975). Therefore, if Ni had any effect on promoting hydrogen absorption, Ni additions could potentially translate into a lower SSC resistance.…”

Section: Effect Of Nickel On Hydrogen Absorption Diffusion and Trapmentioning

confidence: 99%

Sulfide stress cracking of nickel-containing low-alloy steels

et al. 2014

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Low-alloy steels (LAS) are extensively used in oil and gas (O&G) production due to their good mechanical properties and low cost. Even though nickel improves mechanical properties and hardenability with low penalty on weldability, which is critical for large subsea components, nickel content cannot exceed 1-wt% when used in sour service applications. The ISO 15156-2 standard limits the nickel content in LAS on the assumption that nickel concentrations above 1-wt% negatively impact sulfide stress cracking (SSC) resistance. This restriction excludes a significant number of high-strength and high-toughness alloys, such as Ni-Cr-Mo (e.g., UNS G43200 and G43400), Ni-Mo (e.g., UNS G46200), and Ni-Cr-Mo-V grades, from sour service applications and can be used only if successfully qualified. However, the standard is based on controversial research conducted more than 40 years ago. Since then, researchers have suggested that it is the microstructure that determines SSC resistance, regardless of Ni content. This review summarizes the advantages and disadvantages of nickel-containing LAS in terms of strength, weldability, hardenability, potential weight savings, and cost reduction. Likewise, the state of knowledge on the effect of nickel on hydrogen absorption as well as SSC initiation and propagation kinetics is critically reviewed.

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“…Different relationships were proposed to express the effect of tensile stresses on solubility. [25][26][27][28] As is schematically shown in Fig. 2, the crack propagates when a critical concentration of atomic hydrogen is reached at a certain point of the material.…”

Section: Hydrogen Embrittlement Mechanismsmentioning

confidence: 99%

“…Due to the previously mentioned facts, an intensive effort has been done to understand the involved mechanisms and hundreds of papers have been published. [8][9][10][11][12][13][14] Despite those efforts, hydrogen embrittlement mechanisms continue to be widely discussed and different theories have been proposed. However, a generally recognized common feature of all the theories that attempt to explain embrittlement in nonhydride former materials is that some critical concentration of hydrogen must be reached at a potential crack site for failure to initiate.…”

Section: Hydrogen Embrittlement Mechanismsmentioning

confidence: 99%