Influence of casting defects on fatigue crack initiation and fatigue limit of ductile cast iron

Collini, Luca; Pirondi, A.; Bianchi, Roberto; Cova, M.; Milella, Pietro Paolo

doi:10.1016/j.proeng.2011.04.481

Cited by 36 publications

(17 citation statements)

References 8 publications

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“…These defects can be characterized by their type, their size, their morphology and the position according to the free surface. Influence of casting defects on fatigue strength is widely studied for aluminium alloys and steels . However, fewer results can be found for titanium alloys to evaluate the influence of casting defects on the fatigue strength.…”

Section: Introductionmentioning

confidence: 99%

Influence of artificial and casting defects on fatigue strength of moulded components in Ti‐6Al‐4V alloy

Léopold

Nadot

Thomas

et al. 2015

Fatigue Fract Eng Mat Struct

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The influence of defects on the fatigue strength of a cast Ti‐6Al‐4V alloy has been investigated. An experimental programme has been defined with different castings. On a first stage, a flat fatigue specimen has been developed to be representative of the real aircraft component. Then, reference fatigue properties have been determined and reduction of the fatigue strength has been quantified for artificial and natural defects. It is shown that an artificial defect with a chemically milled surface is representative of an in‐service component surface machining: surface pinholes have similar influence on the fatigue behaviour. Furthermore, the experimental results have shown that the geometrical morphology is not the major parameter that governs the fatigue life reduction: the defect type has a major influence. It is also shown that the initiation stage is not negligible in the total fatigue life about 105 cycles. Kitagawa diagrams were built to determine critical defect sizes.

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Section: Introductionmentioning

confidence: 99%

Influence of artificial and casting defects on fatigue strength of moulded components in Ti‐6Al‐4V alloy

Léopold

Nadot

Thomas

et al. 2015

Fatigue Fract Eng Mat Struct

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“…The choice is strongly connected to the knowledge of the detrimental effects of the microstructural defects on the mechanical behavior, specifically ductility and with a reduction of fatigue limit of only 14%, whose main cause has been attributed to the presence of microporosities. Indeed, different works [43][44][45] showed that the fatigue limit is much more sensitive to surface defects than internal defects, where it is observed that micro-shrinkage cavities strongly influence the fatigue behavior of DCI castings. Foglio et al [42] conducted fatigue tests on two different EN-GJS-400 DCI, in one of which the chunky graphite formation was induced by adding Ce-containing inoculants.…”

Section: Introductionmentioning

confidence: 99%

Fatigue and Fracture Resistance of Heavy-Section Ferritic Ductile Cast Iron

Benedetti

Torresani

Fontanari

et al. 2017

Metals

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Abstract:In this paper, we explore the effect of a long solidification time (12 h) on the mechanical properties of an EN-GJS-400-type ferritic ductile cast iron (DCI). For this purpose, static tensile, rotating bending fatigue, fatigue crack growth and fracture toughness tests are carried out on specimens extracted from the same casting. The obtained results are compared with those of similar materials published in the technical literature. Moreover, the discussion is complemented with metallurgical and fractographic analyses. It has been found that the long solidification time, representative of conditions arising in heavy-section castings, leads to an overgrowth of the graphite nodules and a partial degeneration into chunky graphite. With respect to minimum values prescribed for thick-walled (t > 60 mm) EN-GJS-400-15, the reduction in tensile strength and total elongation is equal to 20% and 75%, respectively. The rotating bending fatigue limit is reduced by 30% with respect to the standard EN-1563, reporting the results of fatigue tests employing laboratory samples extracted from thin-walled castings. Conversely, the resistance to fatigue crack growth is even superior and the fracture toughness comparable to that of conventional DCI.

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“…Their influence on fatigue strength is widely studied for aluminium [1] and steels [2]. However, fewer results can be found for titanium alloys [3].…”

Section: Introductionmentioning

confidence: 99%

Influence of casting defects on fatigue strength of an investment cast Ti-6Al-4V alloy

Léopold

Nadot

Méndez

et al. 2014

MATEC Web of Conferences

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Abstract. The influence of casting defects on fatigue strength of an investment cast Ti6Al-4V alloy is investigated. The most common of these defects are: pinhole, linear defect and inclusion. Each of them is currently defined by its size, morphology and position from the surface but is different from each other for a same type. An experimental campaign is defined with different types of defect. The first part of the campaign is focused on the influence of an artificial and spherical defect, considering two different surface conditions. It is shown that fatigue behaviour of this alloy is very sensitive to the surface condition of this artificial defect despite stress concentrations at the tip of the defect. The second part of the campaign is focused on casting defects: reduction of fatigue life is quantified and it is shown that an electro-discharge machined defect cannot be representative of pinhole.

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Influence of casting defects on fatigue crack initiation and fatigue limit of ductile cast iron

Cited by 36 publications

References 8 publications

Influence of artificial and casting defects on fatigue strength of moulded components in Ti‐6Al‐4V alloy

Influence of artificial and casting defects on fatigue strength of moulded components in Ti‐6Al‐4V alloy

Fatigue and Fracture Resistance of Heavy-Section Ferritic Ductile Cast Iron

Influence of casting defects on fatigue strength of an investment cast Ti-6Al-4V alloy

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