Influence of prior austenite grain structure on hydrogen-induced fracture in as-quenched martensitic steels

Latypova, Renata; Seppälä, Oskari; Nyo, Tun Tun; Kauppi, Timo; Mehtonen, Saara; Hänninen, Hannu; Kömi, Jukka; Pallaspuro, Sakari

doi:10.1016/j.engfracmech.2023.109090

Cited by 13 publications

(6 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This quantitative analysis shows the dominance of HEDE activity compared with the HELP activity. The fracture features like QC, IG, TG and IG cracks as seen in Figures 14B to 14D, are also observed in the study reported by Latypova et al, 80 Nagao et al 81 and several other studies. 23,30,31,68 The observed features align with the HELP+HEDE model (HEDE>HELP) of HE, which occurs because of hydrogen concentration above critical.…”

Section: Fracture Toughnesssupporting

confidence: 82%

“…Similar fracture features have been reported previously, further supporting the co-occurrence of these mechanisms. 23,67,80,82 Based on the SEM images, it can be inferred that both the HELP and HEDE (HELP+HEDE) mechanisms were active during the fracture in the present case. Thus, the reduction in the fracture toughness observed in hydrogenated specimens can be attributed to the synergistic action of the HELP and HEDE mechanisms (HELP+HEDE, HEDE>HELP).…”

Section: Fracture Toughnessmentioning

confidence: 59%

See 1 more Smart Citation

The fatigue crack growth behavior of hydrogenated 9Cr‐1Mo steel: An experimental and numerical study

Bharati,

Maity,

Singh

et al. 2024

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

This research investigates the fatigue crack evolution in P91 steel through experiments and extended finite element method (XFEM) simulation for as‐received and hydrogenated conditions. Hydrogen pre‐charging is performed using a constant current electrochemical method in 1 M sulfuric acid solution. The study compares the experimental fatigue crack growth rate (FCGR) of hydrogenated and as‐received conditions and employs an XFEM simulation to replicate FCGR. The results of the experiments reveal an increased FCGR in hydrogenated specimens. Fracture surface analysis confirms the co‐occurrence of the “hydrogen‐enhanced localized plasticity” (HELP) and “hydrogen‐enhanced decohesion” (HEDE) mechanism (HELP+HEDE, HEDE>HELP). The simulation results closely align with the experimental findings, validating the model's accuracy. Consequently, these findings are the basis for proposing a damage tolerance approach‐based numerical algorithm. This algorithm allows the prediction of component integrity by considering a known crack length. Furthermore, fracture toughness (KIQ) was experimentally evaluated to enhance the understanding of the material's mechanical properties.

show abstract

Section: Fracture Toughnesssupporting

confidence: 82%

Section: Fracture Toughnessmentioning

confidence: 59%

The fatigue crack growth behavior of hydrogenated 9Cr‐1Mo steel: An experimental and numerical study

Bharati,

Maity,

Singh

et al. 2024

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

show abstract

“…For equiaxed PAG structure, crack propagation was partly intergranular, leading to faster fractures with abrupt force drops in the final stages of fracturing. [ 11 ] For elongated PAGs with transgranular quasi‐cleavage crack propagation, force decrease was gradual. [ 10 ] Such mechanisms can affect the first‐ and second‐order time derivatives of the force curve.…”

Section: Introductionmentioning

confidence: 99%

Data‐analysis method for hydrogen embrittlement tuning‐fork test

Pohjonen

Latypova

Seppälä

2023

Materials & Corrosion

Self Cite

View full text Add to dashboard Cite

A new data‐analysis method is proposed for processing time‐force data obtained from a recently developed novel tuning‐fork test that has been utilized in hydrogen embrittlement studies. The analysis method is based on the application of suitable functions that are shown to provide a good fit to the data. The fitted functions allow for the calculation of first‐ and second‐order time derivatives from the initially scattered data. The negative peaks of the second‐order derivatives of the fitted functions can be associated with the more sudden changes that could be observed in the experimental data. Since these sudden changes are expected to be related to the operation of the mechanisms at the microstructural level, the present analysis provides a potentially useful method for obtaining knowledge of the operation of these mechanisms.

show abstract

“…TFT has been under development since 2016, being a unique constant displacement test that does not require a tensile test equipment for loading of the specimens [3][4][5][6][7]. TFT has been successfully used for ranking ultrahigh-strength steels according to their susceptibility to HE by combining a controlled tensile stress region in bending with electrochemical hydrogen charging.…”

Section: Introductionmentioning

confidence: 99%

“…Initially, test materials were compared using material-specific threshold stress [3,4]. The clamping system was then further developed, and after the integration of a loadcell inside the clamp, it was possible to determine initiation-time, time-to-fracture, and crack propagation rate from each fracture test [5,6]. TFT had sufficient resolution and it was successfully used in the comparison of ultrahighstrength steels with similar mechanical properties and microstructure but different prior austenite grain (PAG) structure [6].…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Embrittlement in as-Quenched Martensitic Steels - Application of Incremental Step Loading Technique with Novel Tuning-Fork Test

Latypova,

Nyo,

Kömi

et al. 2023

KEM

Self Cite

View full text Add to dashboard Cite

Hydrogen embrittlement (HE) is a well-known issue, especially with ultrahigh-strength steels (UHSS). Various testing methods are utilised to study HE, but they typically require tensile test equipment, or are impractical due to limited stress control with standard geometries. We have developed a novel Tuning-fork test (TFT) to study HE susceptibility of steels with a new specimen geometry, which can be stressed accurately without tensile test equipment. The test method utilises in situ electrochemical hydrogen charging and constant displacement for stressing of the notched specimens by bending. Crack initiation and propagation are controlled with an isolated tensile stress region, and the failure process is monitored with a loadcell. TFT is a simple and fast testing method, which allows ranking of UHSSs, and to investigate, e.g., microstructural effects on susceptibility to HE and H-induced fracture processes. Here in this study, we present the state-of-the-art with the improved more precise second-generation TFT setup, which benefits from a more sensitive loadcell and a more stable fine-tuneable differential screw adjustment. We extend TFT to testing of martensitic steels with nominal hardness from 400 HBW to 600 HBW with the Incremental step loading technique (ISLT). The results show that TFT with ISLT is well applicable for ranking ultrahigh-strength steels based on their susceptibility to HE. Force-time data from ISLT can also be used for the determination of a material-specific threshold stress level, and the last step for the calculation of a crack initiation-time and time-to-fracture. However, the current manual operation of the loading screw can still limit maximum duration of a test.

show abstract

Influence of prior austenite grain structure on hydrogen-induced fracture in as-quenched martensitic steels

Cited by 13 publications

References 36 publications

The fatigue crack growth behavior of hydrogenated 9Cr‐1Mo steel: An experimental and numerical study

The fatigue crack growth behavior of hydrogenated 9Cr‐1Mo steel: An experimental and numerical study

Data‐analysis method for hydrogen embrittlement tuning‐fork test

Hydrogen Embrittlement in as-Quenched Martensitic Steels - Application of Incremental Step Loading Technique with Novel Tuning-Fork Test

Contact Info

Product

Resources

About