Effect of inclusion on subsurface crack initiation and gigacycle fatigue strength

Wang, Hongtao; Bathìas, Claude; Kawagoishi, Norio; Chen, Qiang

doi:10.1016/s0142-1123(02)00037-3

Cited by 358 publications

(182 citation statements)

References 12 publications

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“…For rotating bending, most of interior defects are the types of non-inclusions; only one specimen fractures from interior inclusion for RB150. With the increase of tempering temperature, inclusion initiation becomes dominant for RB150 and RB180 as are often reported in the literature [5,15,22,[27][28][29]. ΔK Inc and ΔK FGA are different from each other for the three heat treatment procedures.…”

Section: Resultsmentioning

confidence: 57%

“…Surface defects may become non-propagating cracks [12], and sometimes grain boundary could also become a crack origin for high carbon chromium steel under low tempering temperature [5,13]. It is also revealed that fatigue crack initiation within FGA is dominated for high cycle fatigue (HCF) and VHCF, and FGA consumes more than 90% fatigue life [14,15]. Thus, microstructure barriers near the fatigue crack origin are responsible for crack initiation and determine the fatigue life scattering.…”

Section: Introductionmentioning

confidence: 99%

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Effects of loading condition on very-high-cycle fatigue behaviour and dominant variable analysis

Lei

Xie

Sun

et al. 2013

Sci. China Phys. Mech. Astron.

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The specimens of a high carbon chromium steel were quenched and tempered at 150°C, 180°C and 300°C. Such specimens were tested via rotating bending and a push-pull type of axial loading to investigate the influences of loading condition on the behaviour of very-high-cycle fatigue (VHCF). Experimental results show the different influences of inclusion size on the fatigue life for the two loading conditions. Predominant factors and mechanism for the fine-granular-area (FGA) of crack origin were discussed. In addition, a reliability analysis based on a modified Tanaka-Mura model was carried out to evaluate the sensitivity of inclusion size, stress, and K FGA to the life of VHCF crack initiation.

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Section: Resultsmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Effects of loading condition on very-high-cycle fatigue behaviour and dominant variable analysis

Lei

Xie

Sun

et al. 2013

Sci. China Phys. Mech. Astron.

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“…(4), and the calculation method is similar with that in Ref. [21]. In this way, (da/dN) FGA is of the magnitude of 10 À 13 m/cycle for fatigue cycles at 10 7 cycles, and of the magnitude of 10 À 12 m/cycle for fatigue cycles at 10 6 cycles.…”

Section: Mean Crack Growth Rate In Fgamentioning

confidence: 99%

“…It is seen that below (FGA) and above (surface fisheye) the threshold, the crack propagation rate differs definitely. Such a low rate of FGA crack, i.e., FGA formation is attributed to the energy accumulation of dislocation movement for VHCF crack initiation in FGA [21].…”

Section: Mean Crack Growth Rate In Fgamentioning

confidence: 99%

Effects of inclusion size and location on very-high-cycle fatigue behavior for high strength steels

Lei

Hong

Xie

et al. 2012

Materials Science and Engineering: A

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a b s t r a c tFatigue tests with rotary bending (52.5 Hz) and ultrasonic cycling (20 kHz) methods were performed, respectively on two high strength steels so as to investigate the effects of inclusion size and location on the fatigue behavior from low cycle fatigue to very-high-cycle fatigue (VHCF) regimes. Under rotary bending test, four fracture patterns were observed with respect to different locations of inclusion on fracture surface. The mean crack growth rate within FGA (fine granular area of crack origin) was estimated to give the value with the magnitude of 10 -13 m/cycle for the specimens with the fracture pattern of ''FGA þ surface fisheye''. Under ultrasonic cycling test, the size effect of inclusions on VHCF was investigated with two groups of specimens. One is with the inclusion size between 20 and 60 mm and the other is with the inclusion size between 10 and 30 mm. The results show that large inclusions lowered the proportion of net FGA at given stress levels and led to the shortening of VHCF life. The degradation of VHCF strength caused by the increase of inclusion size is ascribed to the decrease of the critical stress of FGA formation for large inclusions.

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“…However, the growth of a small fatigue crack is a complex 3D process, especially for surface breaking or sub-surface initiating short cracks which typically have a more complex 3D crack shape than conventional through thickness long cracks. In this case the 3D interaction with other features such as local microstructure [2], residual stress [3], inclusions or second phases [4,5], can significantly affect initiation and propagation behaviour during fatigue since the stress (or strain) intensity distribution around the crack periphery changes. In addition simple measures of fatigue crack growth, da/dN, are based on underlying assumptions of a single crack with a crack driving force that can be described simply (e.g.…”

Section: Introductionmentioning

confidence: 99%

3-D analysis of fatigue crack behaviour in a shot peened steam turbine blade material

Katsamenis

Mellor

et al. 2015

Materials Science and Engineering: A

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Serial mechanical sectioning and high resolution X-ray tomography have been used to study the three-dimensional morphology of small fatigue cracks growing in a 12 Cr tempered martensitic steam turbine blade material. A range of surface conditions has been studied, namely polished and shot peened (with varying levels of intensity). In the polished (unpeened) condition, inclusions (alumina and manganese sulphide) played an important role in initiating and controlling early fatigue crack behaviour. When fatigue cracks initiated from an alumina stringer, the crack morphology was normally dominated by single stringers, which were always in the centre of the fatigue crack, indicating its primary role in initiation. Manganese sulphide inclusion groups however seemed to dominate and affect the crack path along both the surface and depth crack growth directions. The more intensely shot peened condition did not however evidence inclusion or stringer affected fatigue crack initiation or growth behaviour; sub-surface crack coalescence being clearly observed by both serial sectioning and CT (computed tomography) imaging techniques at a depth of about 150 ~ 180 μm. These sub-surface crack coalescences can be linked to both the extent of the compressive residual stress as well as the depth of the plastic deformation arising from the intense shot peening process. Shot peening appears to provide a different defect population that initiates fatigue cracks and competes with the underlying metallurgical defect populations. The most beneficial shot peening process would in this case appear to "deactivate" 2 the original metallurgical defect population and substitute a known defect distribution from the shot peening process from which fatigue cracks grow rather slowly in the strain hardened surface layer which also contains compressive residual stresses. A benefit to fatigue life in bending, even under Low Cycle Fatigue (LCF) conditions, has been observed in these tests if a sufficiently severe shot peening condition is applied in a constrained notch configuration.

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Effect of inclusion on subsurface crack initiation and gigacycle fatigue strength

Cited by 358 publications

References 12 publications

Effects of loading condition on very-high-cycle fatigue behaviour and dominant variable analysis

Effects of loading condition on very-high-cycle fatigue behaviour and dominant variable analysis

Effects of inclusion size and location on very-high-cycle fatigue behavior for high strength steels

3-D analysis of fatigue crack behaviour in a shot peened steam turbine blade material

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