Stepwise <i>S‐N</i> curve and fish‐eye failure in gigacycle fatigue

Nishijima,; Kanazawa,

doi:10.1046/j.1460-2695.1999.00206.x

Cited by 264 publications

(161 citation statements)

References 5 publications

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“…Figure 12 is a schematic S-N diagram. The concept has been firmly established (18) that S-N curves exist independently for surface and internal fractures as shown in Fig. 12 (a), and the two knees observed in an S-N curve of a high strength steel are brought about by superimposition of these two curves.…”

Section: Influences Of Fine Vcs and Modified Ausform-mentioning

confidence: 99%

Gigacycle Fatigue Properties of V-Added Steel with an Application of Modified Ausforming

Hirukawa

Furuya

Matsuoka

2006

JSME Int. J., Ser. A

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This report reveals gigacycle fatigue properties for a modified-ausformed V-added steel with the chemical composition of 0.3 C-0.3 Si-1.0 Cr-0.7 Mo-0.3 V in mass %. Modifiedausformed and oil-quenched steels were prepared for fatigue tests, followed by tempering at 400• C and 600• C. The tensile strengths of the 600 • C tempered steels were almost equal to those of the 400• C tempered versions because of secondary hardening due to fine precipitation of vanadium carbides. The fatigue properties of the 600• C tempered version of oilquenched steel (QT600) showed little difference from the 400 • C tempered version (QT400) in spite of the fine precipitation of vanadium carbides. The modified-ausformed steels (AF400 and AF600) revealed higher fatigue limits at 5 × 10 9 cycles than the oil-quenched versions (QT400 and QT600), although the difference between AF400 and AF600 was small. The remarkable difference between AF400 and AF600 was fatigue strengths at around 10 6 cycles, i.e. the fatigue strength of AF600 at those cycles was higher than that of AF400. Based on the above results, the effect of the fine precipitation of vanadium carbides was small on the gigacycle fatigue properties, while modified-ausforming could improve those properties. On the other hand, the multiple effects of the fine precipitation and modified-ausforming was large on the fatigue strength at around 10 6 cycles.

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Section: Influences Of Fine Vcs and Modified Ausform-mentioning

confidence: 99%

Gigacycle Fatigue Properties of V-Added Steel with an Application of Modified Ausforming

Hirukawa

Furuya

Matsuoka

2006

JSME Int. J., Ser. A

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“…For treated specimens with defects less than 100µm, loaded in tension, crack initiation occurred at subsurface inclusions (Fig.9). This type of fatigue failure surface is often observed in high strength steels [12,13] and is often associated with the Very High Cycle Fatigue domain(VHCF) for different types of material: aluminium alloys from the AlSi and AlMgSi families, copper and titanium alloys and also for the magnesium alloy AZ 91 [14,15,16,17].…”

Section: Tensile Loadsmentioning

confidence: 99%

The effect of quenching and defects size on the HCF behaviour of Boron steel

Pessard

Abrivard

Morel

et al. 2014

International Journal of Fatigue

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. AbstractThis work investigates the effect of natural and artificial surface defects and quenching on the fatigue strength of a Boron Steel (22MnB5). A vast experimental campaign has been undertaken to study the high cycle fatigue behaviour and more specifically the fatigue damage mechanisms observed in quenched and untreated materials, under different loading conditions and with differents artificial defects sizes (from 25µm to 370 µm radius). In order to test the sheet metal in shear an original test apparatus is used. The critical defect size is determined to be 100±50µm. This critical size does not appear to depend on the loading type or the microstructure of the material (i.e. ferritic-perlitic or martensitic). However, for large defects, the quenched material is more sensitive to the defect size than the untreated material. For a defect size range of 100µm to 300µm the slope of the Kitagawa-Takahashi diagram is approximately -1/3 and -1/6 for the quenched and untreated materials respectively. A probabilistic approach that leads naturally to a probabilistic Kitagawa type diagram is developed. This methodology can be used to explain the relationship between the influence of the heat treatment and the defect size on the fatigue behaviour of this steel.

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“…The research results presented by many authors underline their negative impact [26][27][28]. World literature focuses mainly on hard, little plastic steels [7; [28][29][30][31]. There are also works analysing the impact of impurities on fatigue strength of steel with high plasticity [20; 23; 32-33].…”

Section: Introductionmentioning

confidence: 99%

Influence of size and distances between impurities on fatigue strength structural steel for agricultural machines

Lipiński

2018

Engineering for Rural Development

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Abstract. The high-purity low carbon steel properties are influenced by the chemical composition and production technology. The morphology of impurity, its size and content is very important for the quality of high-purity steel. Hard, non-plastic microstructure of steel with impurities as non-metallic inclusions can be one of the factors that influence the fatigue strength of steel. The quantity of non-metallic inclusions results from the content of impurities in the steel, while their size, dispersion, microstructure, phase composition shape and impurity spaces are determined by the course of technological processes in liquid state. The tested material consisted of semi-finished products of highpurity, low-carbon structural steel with: boron, chromium, manganese, molybdenum, nickel and low contents sulfur and phosphorus as impurities. The experimental material obtained in industrial production consisted of structural steel obtained in three series of steel melts in furnaces: electric with desulfurized, electric with desulfurized and next argon-refined and the third series from oxygen converter with vacuum degassed of steel. The technological process consisted of two melting technologies: the first and second in a 140-ton basic industrial arc furnace and the third in a 100-ton oxygen converter. The test specimens were austenitized by treatment at temperature 880 ºC for 30 minutes. Next the samples were cooled in cold water and tempered in different temperatures: 200, 300, 400, 500 and 600 ºC for 120 minutes and cooled on air. The fatigue strength of the samples was tested on a rotary bending machine at a frequency load 6000 rotations per minute. The present work discusses the results of changes in rotary bending fatigue strength of low carbon structural steel hardened and tempered at different temperatures as the influence of size and distance proportions between the impurities of high-purity low carbon steel.Keywords: steel, structural steel, fatigue strength, bending fatigue, impurities. IntroductionThere are many machine elements that work with variable loads. Variable steel load causes material fatigue [1; 3]. Microcrack is formed after crossing the limit of fatigue strength. The microcrack increases along with the lifetime load of the element [4][5][6][7][8]. Low fatigue strength may result in damage to the working element [9-10]. The fatigue cracking results mainly from exceeding the immediate fatigue strength of the material and material imperfection [11][12][13][14][15]. The material imperfection mainly is caused by the production process with the effect on alloy properties in particular fatigue strength [4; 16-18]. Stochastic events are mainly methods allowing to analyse factors for crack of material under the periodically varying loads [10; 19]. The low carbon steels are polycrystalline, consisting of grains with random dimension and shape geometrically separated by grain boundaries often with precipitates forming notches. The grain boundaries themselves often have different properties than the grain t...

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Stepwise S‐N curve and fish‐eye failure in gigacycle fatigue

Cited by 264 publications

References 5 publications

Gigacycle Fatigue Properties of V-Added Steel with an Application of Modified Ausforming

Gigacycle Fatigue Properties of V-Added Steel with an Application of Modified Ausforming

The effect of quenching and defects size on the HCF behaviour of Boron steel

Influence of size and distances between impurities on fatigue strength structural steel for agricultural machines

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