The influence of hydrogen on the very high cycle fatigue property and crack growth characteristics of bearing steels

Ogawa, Takeshi; Hasunuma, Shota; Inatomi, Yosuke; Yasukochi, Natsumi; Shigeta, Shohei

doi:10.1299/mel.18-00134

Cited by 3 publications

(4 citation statements)

References 17 publications

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“…The beach marks were applied to measuring the internal crack growth rates. [8][9][10] As the results, small internal cracks revealed extremely slow crack growth, which occupies most parts of the VHCF life of high-strength steels. This finding led to a new model to predict the VHCF strength of highstrength steels.…”

Section: Internal Crack Growth Rates Measured By Using Beach Marksmentioning

confidence: 78%

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Standardization of an ultrasonic fatigue testing method in Japan

Furuya

Shimamura

Takanashi

et al. 2022

Fatigue Fract Eng Mat Struct

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The ultrasonic fatigue testing method was standardized in the Japan Welding Engineering Society. Scope of this standard is limited for metallic materials tested at room temperature. This standard applies not only to axial loading by longitudinal oscillation but also to torsional loading by torsional oscillation.The stipulated specimens are an hourglass-shaped type, while other types of specimens are also acceptable. Explanation attached to this standard discloses data and theories behind each requirement. In particular, massive data are disclosed for a frequency effect with comparisons of the data between ultrasonic and conventional fatigue testings. The data are disclosed on low-and highstrength steels, austenitic stainless steels, cast irons, titanium alloys, and aluminum alloys. These data suggest that the ultrasonic fatigue testing is well suited to high-strength materials but not low-strength materials. In addition to the introduction of the standard, studies using the ultrasonic fatigue testing are exampled in this paper.

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Section: Internal Crack Growth Rates Measured By Using Beach Marksmentioning

confidence: 78%

“…The created beach marks are small enough to observe a small internal crack just after crack initiation. The beach marks were applied to measuring the internal crack growth rates 8–10 . As the results, small internal cracks revealed extremely slow crack growth, which occupies most parts of the VHCF life of high‐strength steels.…”

Section: Examples Of Studiesmentioning

confidence: 99%

Standardization of an ultrasonic fatigue testing method in Japan

Furuya

Shimamura

Takanashi

et al. 2022

Fatigue Fract Eng Mat Struct

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

“…The FGA region shows some characteristic properties, for example, increased roughness on the fracture surface [ 19 ]. Further, the FGA size correlates with the applied load amplitude and with the fatigue life [ 12 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. It is also assumed [ 5 , 6 , 27 , 28 ] that the cyclic stress intensity Δ K FGA , which is calculated at the border of the FGA, corresponds to the cyclic long crack growth threshold value Δ K th,lc .…”

Section: Introductionmentioning

confidence: 99%

Internal Crack Initiation and Growth Starting from Artificially Generated Defects in Additively Manufactured Ti6Al4V Specimen in the VHCF Regime

et al. 2021

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The aim of the present work was to investigate the ‘fine granular area’ (FGA) formation based on artificially generated internal defects in additively manufactured Ti6Al4V specimens in the early stage of fatigue crack growth in the ‘very high cycle fatigue’ (VHCF) regime. Fatigue tests were performed with constant amplitude at pure tension-compression loading (R = −1) using an ultrasonic fatigue testing setup. Failed specimens were investigated using optical microscopy, high-resolution ‘scanning electron microscopy’ (SEM), and ‘focused ion beam’ (FIB) techniques. Further, the paper introduces alternative proposals to identify the FGA layer beneath the fracture surfaces in terms of the ‘cross section polishing’ (CSP) technique and metallic grindings with special attention paid to the crack origin, the surrounding microstructure, and the expansion of the nanograin layer beneath the fracture surface. Different existing fracture mechanical approaches were applied to evaluate if an FGA formation is possible. Moreover, the results were discussed in comparison to the experimental findings.

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When do small fatigue cracks propagate and when are they arrested?

Stanzl-Tschegg

2019

Corrosion Reviews

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The formation of small and long cracks and their propagation or arrest are treated drawing special attention to the (a) impact of environment and (b) several loading parameters (R-ratio, stress/strain-amplitude, constant-amplitude and variable-amplitude loading, superimposed loading, ultrasonic fatigue loading, and frequency effects) for three groups of metallic materials (two high-strength steels, 7075 and 2024 Al alloys, polycrystalline copper). The influence of these parameters on lifetimes and fatigue crack propagation behavior being determined by microstructural features on all levels of magnification (ranging from several millimeters to nanometers) is presented. A review of the state of knowledge according to literature is given in the introduction. The following results were obtained, and models for their interpretation were presented: The development (growth or arrest) of small cracks into a long crack is driven by several competing processes (due to material, way of loading, environment, etc.). The environment plays a predominant role. Especially in the high-cycle and very-high cycle regime, the complexity of interacting processes needs further – mainly experimental – investigations. Some further studies relate to different loading conditions and possibilities of testing considering newly developed material. Experiments in high vacuum have to form the basis for studying environmentally assisted fatigue response.

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The influence of hydrogen on the very high cycle fatigue property and crack growth characteristics of bearing steels

Cited by 3 publications

References 17 publications

Standardization of an ultrasonic fatigue testing method in Japan

Standardization of an ultrasonic fatigue testing method in Japan

Internal Crack Initiation and Growth Starting from Artificially Generated Defects in Additively Manufactured Ti6Al4V Specimen in the VHCF Regime

When do small fatigue cracks propagate and when are they arrested?

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