Numerical Modelling of Hydrogen Assisted Cracking in Steel Welds

Boellinghaus, Thomas; Mente, Tobias; Wongpanya, Pornwasa; Viyanit, Ekkarut; Steppan, Enrico

doi:10.1007/978-3-319-28434-7_18

Cited by 8 publications

(1 citation statement)

References 73 publications

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“…[117,118] This is due to the increase in local hydrogen solubility which promotes the formation of bonds between Fe ions and hydrogen atoms at crack tip when electrons are donated to fill the highest energy-level orbital of Fe. [119,120] On the other hand, HELP is when absorbed hydrogen decreases the projected shear stress from one dislocation to another, in turn lowering the stress required to move a dislocation through obstacles. [121] Finally, the AIDE theory involves adsorbed hydrogen within the first few layers of atoms at crack tip leading to localized HEDE.…”

Section: Overview Of He Mechanisms At Crack Tipmentioning

confidence: 99%

A Review of the Factors That Can Increase the Risk of Sulfide Stress Cracking in Thermomechanical Controlled Processed Pipeline Steels

Hiew Sze Kei,

van Haaften,

Britton

et al. 2023

Adv Eng Mater

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This review aims to improve our understanding of the important factors which influence the susceptibility of thermomechanical controlled processed (TMCP) steels to sulfide stress cracking (SSC). Mechanisms involved in hydrogen embrittlement (HE) from three perspectives are focused on: the microstructure constituents of TMCP steels; environmental factors; and fracture mechanism of SSC. Microstructures are reviewed as they affect the diffusion and trapping of hydrogen that can reduce the resistance to fracture. Environmental factors discussed highlight that when exposed to an aqueous H2S environment, a sulfide layer can form and influence the ingress of hydrogen, and this is affected by pH, temperature, and H2S partial pressure. Fracture is influenced by the nature of the crack tip and the crack tip plastic zone during crack propagation, and hydrogen can significantly affect crack tip growth. This review provides a critical assessment of the interplay between these three factors and aims to provide understanding to enhance our engineering approaches to manage and mitigate against fracture of TMCP steels.

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Section: Overview Of He Mechanisms At Crack Tipmentioning

confidence: 99%

A Review of the Factors That Can Increase the Risk of Sulfide Stress Cracking in Thermomechanical Controlled Processed Pipeline Steels

Hiew Sze Kei,

van Haaften,

Britton

et al. 2023

Adv Eng Mater

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Determination of critical local straining conditions for solidification cracking at laser beam welding by experimental and numerical methods

Bakir,

Gumenyuk,

Rethmeier

2024

Proc Appl Math and Mech

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The phenomenon of solidification cracking has been the subject of numerous research projects over the years. Great efforts have been made to understand the fundamentals of hot cracking. It is generally agreed that solidification cracks form in the solidification range between the liquidus and solidus temperatures under the combination of thermal, metallurgical and mechanical factors. There is still a need to determine the time‐resolved strain distribution in the crack‐sensitive region in order to analyse the local critical conditions for solidification cracking phenomena. This was a strong motivation for the development of a measurement system used in this study to estimate the local strains and strain rates in the zone where the solidification crack is expected to occur. The laser beam welding experiments were conducted using the Controlled‐Tensile‐Weldability test (CTW test) to apply an external strain condition during welding to generate solidification cracks. The CTW test is a test method for investigating the susceptibility of laser‐welded joints to solidification cracking, in which the sample can be subjected to a defined strain at a defined strain rate during welding.In combination with experimental investigations, numerical simulations provide spatially detailed and time‐dependent information about the strain development during the welding process, especially regarding the critical conditions for solidification cracking. Therefore, this tool was also used in the present study to evaluate the accuracy of measurement methods and to estimate experimentally derived values and their concrete influence on the formation of solidification cracks. By integrating experimental methods and numerical simulations, this study investigates the spatially resolved and temporally changing development of strain during welding, with a particular focus on the critical conditions that lead to the formation of solidification cracks. The use of numerical simulations serves a dual purpose by validating the accuracy of measurement methods and examining experimentally determined values for their actual influence on the formation of solidification cracks. A three‐dimensional finite element (FE) model implemented with ANSYS is used to simulate strains and stresses during welding. The credibility of the model was first established by validation using experimental temperature measurements. Subsequently, structural simulations were carried out under external load. The results of the simulations showed commendable agreement with the strain measurements performed using the developed technique.

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