Hydrogen Damage Research Articles

The adverse effect of grain refinement on hydrogen embrittlement in a high Mn austenitic steel

This study presents a novel observation wherein the reduction in grain size (GS) from 20 μm to 1 μm in austenitic steel adversely affects hydrogen embrittlement (HE). The findings indicate an increase in total absorbed hydrogen with grain refinement when subjected to cathodic hydrogen charging. The results demonstrate that even with grain refinement to 1 μm, the primary mode of hydrogen damage remains intergranular, with a significant increase in relative elongation loss (REL%). This phenomenon is attributed to the early nucleation of intergranular hydrogen-induced cracks (HICs) and the accelerated propagation rates of HICs, leading to local stress increments and rapid alloy failure. The accelerated development of HICs is ascribed to the impact of grain refinement on intensified normal stress exerted on grain boundary planes, as well as the suppression of ε-martensite and its positive effect on crack arresting. Besides the enhanced degradation rate of the hydrogen-affected area (HAA) due to grain refinement, the higher ratio of HAA to the entire cross-sectional area was identified as a crucial factor contributing to rapid failure and the inverse effect of grain refinement on HE resistance.

Effects of hydrogen on the fretting wear behavior of laser cladded FeCoCrNiMo0.2 high entropy alloy coating

This study investigates laser-cladded high entropy alloy (HEA) coatings on high-speed train axles to enhance wear resistance under specific fretting conditions. Axles in humid and acidic environments absorb hydrogen, leading to accumulation in grain boundaries, which weakens their structure and causes damage under alternating stress. Despite this, the impact of hydrogen damage on the fretting wear behavior of HEA coatings has not been explored. To address this, we performed fretting wear tests on a laser-cladded FeCoCrNiMo0.2 coating and a GCr15 steel ball friction system, evaluating their performance before and after hydrogen exposure. The results of the study indicate that under a constant load of Fn = 10N and a displacement amplitude of D = 50 μm, the friction coefficient, maximum wear depth, wear volume, and wear rate increased when the system was in the hydrogen charging state compared to the non-hydrogen charging state. Specifically, the friction coefficient increased from 0.60 to 0.93, the maximum wear depth increased from 2.82 μm to 3.63 μm, the wear volume increased from 14.106 × 104μm3 to 22.098 × 104μm3, and the wear rate increased from 28.213 × 10−6 mm/Nm to 36.600 × 10−6 mm/Nm. Under the hydrogen charging state, the friction coefficient, maximum wear depth, wear volume, and wear rate all increased. This is due to hydrogen damage, including the formation of pitting pits and cracks on the surface of the coating, stress concentration, and brittle failure caused by hydrogen infiltration into the material. The presence of hydrogen makes the surface of the coating more prone to detachment, resulting in finer wear debris, deeper grooves, and increased oxidation. These factors accelerate the wear of the coating. This finding will contribute to the development and improvement of advanced surface modification techniques for materials in the hydrogen environment.

Advancing Hydrogen Gas Utilization in Industrial Boilers: Impacts on Critical Boiler Components, Mitigation Measures, and Future Perspectives

This review sets out to investigate the detrimental impacts of hydrogen gas (H2) on critical boiler components and provide appropriate state-of-the-art mitigation measures and future research directions to advance its use in industrial boiler operations. Specifically, the study focused on hydrogen embrittlement (HE) and high-temperature hydrogen attack (HTHA) and their effects on boiler components. The study provided a fundamental understanding of the evolution of these damage mechanisms in materials and their potential impact on critical boiler components in different operational contexts. Subsequently, the review highlighted general and specific mitigation measures, hydrogen-compatible materials (such as single-crystal PWA 1480E, Inconel 625, and Hastelloy X), and hydrogen barrier coatings (such as TiAlN) for mitigating potential hydrogen-induced damages in critical boiler components. This study also identified strategic material selection approaches and advanced approaches based on computational modeling (such as phase-field modeling) and data-driven machine learning models that could be leveraged to mitigate potential equipment failures due to HE and HTHA under elevated H2 conditions. Finally, future research directions were outlined to facilitate future implementation of mitigation measures, material selection studies, and advanced approaches to promote the extensive and sustainable use of H2 in industrial boiler operations.

Influence of hydrogen ingress and capture on the mechanical properties of spray formed 2195 aluminum alloy

The current research has focused on the hydrogen capturing and its impact on the mechanical properties of spray-formed 2195 (SF2195) aluminum alloy. Microstructure characterization, thermal desorption spectra (TDS) and hydrogen trapping of characteristic microstructure, are used to investigate the generation, migration and trapping of hydrogen. The retention of moisture in the carrier gas is believed to induce high concentration of hydrogen and the amorphous Al2O3 layer within the SF2195 billet, and the local retention of carrier gas brings about pores with the Al2O3 layer on the inner wall. High concentration of hydrogen is captured in the hot-rolled alloy while around 60 % of the hydrogen can be eliminated during the solution-quenching. Particles of T1 phase trap large quantity of hydrogen and the high-density dislocations developed from the pre-stretch promote the migration of hydrogen towards dispersoids and precipitates. The presence of hydrogen and Al2O3 layer contributes to the reduced plasticity of SF2195 alloy. The spreading of flattened pores can induce intensified hydrogen damage effect in local regions and thus contribute to the unusually decreased ductility along the thickness direction in the T8 aged alloy.

Understanding the Phenomenon of High Temperature Hydrogen Attack (HTHA) Responsible for Ferrito-Pearlitic Steels Damage

This article focuses on the fine characterization of steels commonly used in the petrochemical industry damaged by the phenomenon of high temperature hydrogen attack (HTHA). The study was conducted in two steps. To begin with, a damaged 0.5-Mo pearlitic steel from the petroleum refineries, submitted to HTHA for decades, was characterized in detail using multiscale electron microscopy techniques. As part of an upstream study to better understand the onset and the growth of cavities, a brand new SA516 grade 60 low carbon–manganese steel was subsequently exposed to accelerated HTHA conditions through interrupted cycles carried out in autoclaves and then examined. Numerous cavities, plausibly filled with methane, were noticed in both materials. These cavities were mostly located at ferrite–pearlite grain boundaries along carbides and at triple grain boundaries near large carbides. The 0.5-Mo pearlitic steel showed cavities reaching significant sizes, up to 1 µm, but surprisingly no cracks were observed in the depth of the pipe. The major outcome is that 3D focused ion beam–scanning electron microscopy combined with transmission electron microscopy (TEM) analyses unveiled different natures of precipitates as well as in and nearby HTHA cavities for both 0.5-Mo and low carbon–manganese steels. Inclusions, likely AlN, but also Mo- and Cu-rich precipitates were observed in cavities of the industrial steel. These results confirmed a previous study performed on a similar industrial steel that drew a possible correlation between cavities nucleation and the intersection of transgranular inclusion-enriched plane with a grain boundary or carbides in pearlite grains (Flament in Microscopy and Microanalysis 28:1602–1604, 2022).

Near-surface self-resistance hydrogen effect of eutectic high-entropy alloy AlCoCrFeNi2.1

A series of engineering application studies related to hydrogen damage has been carried out for the eutectic high-entropy alloy (HEA) AlCoCrFeNi2.1 with excellent comprehensive properties. This work mainly introduces the element segregation and microstructure evolution phenomenon near the surface phase boundary and around the precipitated phase found in the hydrogen damage experiment of the material. Studies have shown that the evolution of the near-surface phase boundary microstructure of HEAs caused by hydrogen charging has a great influence on the hydrogen trap density inside the alloy. The “self-resistance hydrogen effect” is produced, that is, hydrogen-induced microstructure evolution causes the effect of delayed hydrogen diffusion. In this phenomenon, the synergy between hydrogen atoms and vacancies and dislocations on the alloy surface is crucial.

Hydrogen embrittlement of the nickel alloy UNS N07718 for two different heat-treating schedules

The role of the nickel alloy 718 microstructure has been widely discussed and it is well established the δ phase detrimental effect on the material’s ductility and toughness when exposed to hydrogen. However, other microstructural features that might influence the embrittlement process are more elusive, which requires more in-depth studies. Having selected heat-treating schedules to mitigate δ phase precipitation, this work aims to assess the hydrogen embrittlement of two alloy 718 variants with nominal yield strengths of 120 and 150 ksi. Fundamentally, the idea is to understand the extent of the hydrogen damage caused by an increase in mechanical strength beyond the limit of 140 ksi specified in the API 6ACRA. Slow strain rate (SSR) and fracture toughness (FT) testing were applied to evaluate the mechanical behavior under cathodic polarization. The microstructure of both variants is comprised of recrystallized austenite grains and a very low content of grain boundary δ phase. Nanosized disk-shaped γ″ particles are also present for both variants, although the 150 ksi material shows a higher volume fraction and a finer distribution of this phase. Despite having the same overall fracture features, nanostructure differences between the variants and the consequent impact on hydrogen apparent solubility and slip planarity produced lower values of plastic elongation and initiation fracture toughness for the stronger material.

Comparative study of linear and nonlinear ultrasound applied to the detection of hydrogen damage in 7N01 aluminum alloy

7N01 aluminum alloy samples with different hydrogen damage degrees were prepared by electrochemical hydrogen charging technology. 7N01 aluminum alloy samples with different degrees of hydrogen damage were characterized by metallographic observation, hardness test and XRD test. The results show that the hydrogen content increases with the increase of hydrogen charging time. The surface of aluminum alloy is exfoliated and pits appear. The more severe the hydrogen damage, the greater the depth of pits. The microhardness of the 7N01 aluminum alloy decreases after hydrogen damage, which only occurs near the surface. After electrochemical hydrogen charging, AlH3 appears in the structure of 7N01 aluminum alloy, which is the result of increased hydrogen concentration. The ultrasonic echo signals of hydrogen damaged samples were obtained by a high frequency longitudinal probe ultrasonic detection device, and the results of linear and nonlinear ultrasonic detection were compared. Traditional linear ultrasonic detection parameters such as sound velocity and attenuation coefficient do not change significantly in the early stage of hydrogen damage, but increase significantly in the late stage of hydrogen damage. Due to the change of microstructure, the nonlinear coefficient increases approximately linearly in the early stage of hydrogen damage and decreases in the late stage of hydrogen damage. This study demonstrates the potential for combining linear and nonlinear ultrasonic measurements in hydrogen environment to more comprehensively study hydrogen damage.

Comparison of the hydrogen damage of different rolling surfaces of TC4 Ti alloy sheet

Abstract The microstructure of three rolling surfaces of TC4 sheet is different, and their resistance ability to hydrogen damage lacks systematic research. Thus, the hydrogen damage behavior of TC4 rolling sheet was investigated in this paper. The hydrogen diffusion law along different rolling directions and the precipitation of hydrides on different rolling surfaces were compared. It is found that the shape and distribution of α and β phases are changed under the action of extrusion force during the rolling process, and they are arranged in striped shape on the R-N surface along the R direction, and the diffusion of hydrogen along the R direction is faster due to the existence of continuous β phases as hydrogen diffusion channels, resulting in the more serious hydrogen damage. Besides the hydrides mainly deposited at the α and β phase boundaries, the hydrides precipitated in the interior of α phases on the R-N surface are more than that on the R-T surface due to the different distribution state of β phases.

Hydrogen blistering and cracking of high-strength pipeline steel welds produced by electrochemical hydrogen charging

Pipeline steel system always faces a challenge of hydrogen embrittlement (HE) not only due to corrosion environments but also because of cathodic protection strategy. Especially in welded joint, heterogeneous microstructures lead to the difference in intrinsic HE resistance for different subzones. However, this aspect was often neglected when external loading was applied during evaluation of the HE. To eliminate the effect of external loading, the hydrogen damage behaviors of X100 pipeline steel weld were investigated only based on electrochemical hydrogen charging and the intrinsic HE resistance of each subzone was explored. The results showed that the HE resistance of the main regions in weld was decreased in order of weld metal, heat affected zone (HAZ) and base metal (BM), with different surface damage modes: the BM had predominantly hydrogen blistering; while others displayed mainly hydrogen cracking. The corresponding features for cross-sectional cracking were intergranular propagation along the pancaked grain boundaries in the BM and trangranular propagation in HAZ. For transgranular cracking propagation, the path first trended to initiate on the {100} cleavage plane, then grew on the {110} slip planes. The intergranular cracking was mainly attributed to the lamellar-structural prior grain boundaries that inherited numerous deformation dislocations during hot rolling of the base metal.

Effect of electrochemical charging on the hydrogen embrittlement susceptibility of a low-alloyed tempered martensitic steel submitted to high internal pressure

The influence of hydrogen on the mechanical behavior of a quenched and tempered 42CrMo4 steel has been evaluated by means of high internal pressure fracture tests carried out on hydrogen precharged notched cylindrical specimens. The notched cylindrical specimens were precharged for 3 h time with 1.2 mA/cm2 in two different aqueous media: 1 M H2SO4 added with 0.25 g/l As2O3 and 3.5% of NaCl solution. Hydraulic fracture tests were performed at different ramps of pressure: 7000, 220, 80, 60 and 30 MPa/h, respectively. Hydrogen damage was more marked when the acid aqueous medium (1 M H2SO4 + 0.25 g/l As2O3) was employed. In this case, a higher hydrogen concentration was introduced, leading to hydrogen decohesion micromechanisms (HEDE) near the notched region, especially when tests were performed at 60 MPa/h. Hydrogen embrittlement susceptibility is discussed in terms of the microstructural singularities and the operative fracture micromechanisms observed in each case.

Applied electric field to repair metal defects and accelerate dehydrogenation

Repairing metal micro-defects at the atomic level is very challenging due to their random dispersion and difficulty in identification. At the same time, the interaction of hydrogen with metal may cause hydrogen damage or embrittlement, endangering structural safety. As a result, it is critical to speed up the dehydrogenation of hydrogen-containing materials. The applied electric field can repair the vacancy defects of the material and accelerate the dehydrogenation of the hydrogen-containing metal. The influence of the external environment on the diffusion coefficient of hydrogen in polycrystalline metals was researched using molecular dynamics in this article, and the mechanism of hydrogen diffusion was investigated. Simultaneously, the mechanical characteristics of Fe3Cr alloy were compared during typical heat treatment and electrical treatment. The effect of temperature, electric field strength, and electric field direction on the diffusion coefficient was investigated using orthogonal test analysis. The results demonstrate that temperature and electric field strength have a significant impact on the diffusion coefficient. The atom vibrates violently as the temperature rises, breaking past the diffusion barrier and completing the atomic transition. The addition of the electric field adds extra free energy, decreases the atom’s activation energy, and ultimately enhances the atom’s diffusion coefficient. The repair impact of vacancy defects under electrical treatment is superior to that of typical annealing treatment for polycrystalline Fe3Cr alloy. The electric field can cause the dislocation to migrate, increasing the metal’s toughness and plasticity. This research serves as a useful reference for the electrical treatment of metal materials and offers a method for the quick dehydrogenation of hydrogen-containing materials.

Mitochondria as a key target of molecular hydrogen

The aim of the work was to systematize the data on the biologically significant effects of molecular hydrogen to uncover the mechanisms of its effect on the human body. The paper analyzes the literature on the effect of molecular hydrogen administered in the form of inhalation and hydrogenenriched water on the human body, on laboratory mammals (rats, mice), and on model cell systems in vitro. As a result, a mechanism has been proposed according to which, in addition to the already known effect of hydrogen in neutralizing highly reactive oxygen species, there is at least one other group of molecules that are the target of molecular hydrogen in the body. These are the porphyrins, which are part of the hemoproteins, in particularly the cytochromes of the mitochondrial respiratory chain. In the presence of high concentrations of carbon dioxide, which is formed in the tricarboxylic acid cycle in the mitochondrial matrix, hydrogen damages some of the hemes as a result of covalent binding of the CO group to them. At low doses of hydrogen, this causes a moderate decrease in mitochondrial potential and stimulates the adaptive response of the body, including activation of the transcription factor Nrf2, expression of the heme oxygenase and antioxidant defense enzymes, mitophagy, and renewal of the mitochondrial population in the cell.Conclusion. Molecular hydrogen is an adaptogen that causes mitochondrial hormesis – the renewal and strengthening of the body’s bioenergetic and antioxidant systems.

Research Progress and Prospects on Hydrogen Damage in Welds of Hydrogen-Blended Natural Gas Pipelines

Hydrogen energy represents a crucial pathway towards achieving carbon neutrality and is a pivotal facet of future strategic emerging industries. The safe and efficient transportation of hydrogen is a key link in the entire chain development of the hydrogen energy industry’s “production, storage, and transportation”. Mixing hydrogen into natural gas pipelines for transportation is the potential best way to achieve large-scale, long-distance, safe, and efficient hydrogen transportation. Welds are identified as the vulnerable points in natural gas pipelines, and compatibility between hydrogen-doped natural gas and existing pipeline welds is a critical technical challenge that affects the global-scale transportation of hydrogen energy. Therefore, this article systematically discusses the construction and weld characteristics of hydrogen-doped natural gas pipelines, the research status of hydrogen damage mechanism, and mechanical property strengthening methods of hydrogen-doped natural gas pipeline welds, and points out the future development direction of hydrogen damage mechanism research in hydrogen-doped natural gas pipeline welds. The research results show that: ① Currently, there is a need for comprehensive research on the degradation of mechanical properties in welds made from typical pipe materials on a global scale. It is imperative to systematically elucidate the mechanism of mechanical property degradation due to conventional and hydrogen-induced damage in welds of high-pressure hydrogen-doped natural gas pipelines worldwide. ② The deterioration of mechanical properties in welds of hydrogen-doped natural gas pipelines is influenced by various components, including hydrogen, carbon dioxide, and nitrogen. It is necessary to reveal the mechanism of mechanical property deterioration of pipeline welds under the joint participation of multiple damage mechanisms under multi-component gas conditions. ③ Establishing a fundamental database of mechanical properties for typical pipeline steel materials under hydrogen-doped natural gas conditions globally is imperative, to form a method for strengthening the mechanical properties of typical high-pressure hydrogen-doped natural gas pipeline welds. ④ It is essential to promptly develop relevant standards for hydrogen blending transportation, welding technology, as well as weld evaluation, testing, and repair procedures for natural gas pipelines.

A novel strategy for estimating the diffusion behavior of hydrogen in metallic materials with the combined effect of stress corrosion and hydrogenation: Case study of 2.25Cr-1Mo-0.25V high-strength steel

Hydrogen equipment for long-term service in complex hydrogen environment is threatened by the phenomenon of hydrogen-induced damage, and the combined effect of stress corrosion and hydrogen attack can intensify the formation and development of hydrogen damage. In this study, a new strategy to indirectly estimate the hydrogen diffusivity of metallic materials under tensile stress was proposed by combining the electrochemical hydrogen permeation test (EHPT), the hydrogen diffusion descriptive equation based on Fick's law, and hydrogen pre-charged tensile test. The results revealed that the hydrogen permeation curve obtained after considering the effect of the residual hydrogen extraction stage was highly approximate to the theoretical trend. The hydrogen embrittlement (HE) susceptibility of the pre-tensioned tensile and hydrogen-charged specimens increased with increasing stress. At tensile stress (0–400 MPa) the effective hydrogen diffusivity of 2.25Cr-1Mo-0.25 V steel was: Deff=1.1686+0.4842×exp(σ/277.869). The micrograph from the fracture surfaces also reflected the aggravated brittle fracture characteristics of the steel.

Hydrogen defect acoustic emission recognition by deep learning neural network

Hydrogen attack is the major failure cause of hydrogen equipment breakdown maintenance. Especially, common problems like cracks frequently occur but are challenging to find while operating, presenting an issue for safety and production. In the process of hydrogen damage evolution, a method for defect state recognition is proposed in this paper. Acoustic emission (AE) technology is used for inspecting the entire hydrogen charging process. The characteristic parameters including the counts and duration of the AE signals are first preprocessed, and the current damage states such as the dislocation propagation, and the occurrence of cracks are identified. Then, a deep learning convolutional neural network is used to create a hydrogen defect recognition (HDR) model with the input of a short-time Fourier transform for the feature vector extraction of various damage status AE signals. Finally, the hydrogen defect recognition experiment revealed that HDR is better in classification accuracy at 98.37% due to dislocation propagation and cracks identification. The study can provide an online damage recognition approach for damage state early warning and evaluation to guarantee hydrogen equipment safety operation.

Mitigating high temperature hydrogen attack with interphase precipitation

The attack on steel by reaction with high-pressure hydrogen at elevated temperatures can jeopardise structural integrity in oil & gas industries. Following dissociation, the hydrogen penetrates the steel to react with the carbon present in the ferrite to form methane bubbles within the microstructure. This depletion of carbon in the ferrite causes the dissolution of carbides in order to maintain the ferrite-carbide equilibrium. Therefore, thermodynamically more stable carbides which cause a reduced activity of carbon improve the stability of the steel to hydrogen attack. In this work, we investigate specifically the response of the interphase precipitation of alloy carbides that form during the transformation from γ to α, on hydrogen attack. It is demonstrated quantitatively that the vanadium carbides thus produced enhance the resistance to attack when compared with data from an earlier study involving current, commercially-used steel in the petrochemical industries.

Hydrogen damage process of dual-phase Ti-6Al-4V alloy: From surface passive film to the interior substrate

Hydrogen damage process of dual-phase Ti-6Al-4V alloy: From surface passive film to the interior substrate

Condition assessment of underground corroded pipelines subject to hydrogen damage and combined internal pressure and axial compression

In this work, a 3D finite element (FE) based model was developed to assess the condition of an underground hydrogen transmission pipeline containing a corrosion defect under combined internal pressure and soil movement-induced axial compression. The use of mechanical properties of X100 pipeline steel under different hydrogen charging time models the degree of hydrogen damage in pipelines. Parameter effects, i.e., axial compressive stress, hydrogen damage, defect geometries, and pipeline diameter-to-thickness ratio, were determined. The results demonstrated that the synergistic effect of axial compression, internal pressure, corrosion, and hydrogen damage can lead to a significant decrease in the failure pressure of pipelines. The failure pressure decreased with the wall thickness reduction and increased hydrogen damage, axial compressive stress, defect length, defect depth, and pipe diameter. The competitive effect was observed between the degree of metal loss and hydrogen damage in determining the burst capacity of pipelines. In situations where the pipeline integrity was severely compromised, the failure pressure exhibited minimal reduction despite the increasing severity of hydrogen damage. The stress distribution at the defect zone was influenced by axial compressive stress but remained unaffected by hydrogen damage under normal operating conditions (i.e., an internal pressure of 10 MPa). This work is expected to help operators understand the applicability of elder and in-service pipelines for hydrogen transmission.

Evaluation and Simulation of HTHA Damaged Specimen using UT Advanced Techniques

High Temperature Hydrogen Attack (HTHA) is a wellknown phenomenon that impacts the design, operation, and maintenance for syngas production facilities (e.g., hydrogen and carbon monoxide plants). Recommendations regarding material selection and inspection are given by API 941 and API RP 586 [1], that is currently under revision after Tesoro accident. The new rules have highlighted the need to adapt inspection with more advanced NDT methodology, improving the detection of early stage HTHA damage, then supporting a Fitness for Service approach. This paper makes an overview of various projects funded by Materials Technology Institute (MTI) regarding the assessment and improvement of the performance of such UT advanced NDT for HTHA detection, by means of CIVA UT simulations after a detailed metallographic review and statistical modeling of material inclusions and HTHA damage distributions of field samples. HTHA damage inputs and comparisons between experimental and simulated UT images are consistent for different damaged samples (different levels and types of damage, especially for welded samples), different UT acquisition settings and different inspection frequencies. The unprecedented use of HTHA damage distribution laws and NDT simulations of nonmetallic defects and HTHA damage are promising tools which may then used to assess the limits of existing NDT and to define optimized probes and procedures relying on advanced ultrasonic examinations.