Rolling Contact Fatigue Failure Mechanisms of Plasma-Nitrided Ductile Cast Iron

Wollmann, Daniela; Soares, Gustavo Pazzianotto; Grabarski, Marina Izabelle; Weigert, Nathalia Beatriz; Escobar, Jairo Arturo; Pintaúde, Giuseppe; Neves, Julio Cesar Klein das

doi:10.1007/s11665-017-2717-4

Cited by 8 publications

(3 citation statements)

References 24 publications

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“…For distributions with n < 20 it is recommended to plot the curves using the X regression method (RRX) [52]. The use of the con dence interval is fundamental for the material life analysis, especially in small sample size [26,27,53]. The con dence interval shows a plausible range of variation that the value of the parameter of interest can assume.…”

Section: Weibull's Statistical Analysismentioning

confidence: 99%

Correlation between roughness, film thickness, and friction coefficient with pitting wear resistance of spur gears

Dalcin,

de Menezes,

da Silva Rocha

et al. 2023

Int J Adv Manuf Technol

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The present investigation aims correlate the roughness, lm thickness and friction coe cient with pitting wear resistance along the rolling-sliding contact fatigue of forged and plasma nitrided gears. The hypothesis of this work is that the pitting wear resistance of forged gears can be greatly improved by pulsed plasma nitriding. Weibull's statistical analysis con rms that nitrided gears with 24 vol.% N 2 showed the lowest pitting wear rates among the investigated conditions, which was attributed to the best combination between surface hardness, fracture toughness, compound layer thickness, and phases on surface. The pitting wear intensi es with increasing roughness, but this same behavior was not observed between the wear evolution and the maximum shear stress eld in the sub-surface. Another interesting fact is that nitrided gears with 24 vol.% N 2 (best condition), have a greater lm thickness at the end of the rolling-sliding contact fatigue, which gives it greater protection, less friction and pitting wear.

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Section: Weibull's Statistical Analysismentioning

confidence: 99%

Correlation between roughness, film thickness, and friction coefficient with pitting wear resistance of spur gears

Dalcin,

de Menezes,

da Silva Rocha

et al. 2023

Int J Adv Manuf Technol

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“…They show that plasma nitriding carried out at low temperatures and short times, can increases the surface hardness without change roughness pattern of the previously textured surface. Another interesting research was carried out by Wollmann et al [9], which investigated the rolling contact fatigue (RCF) of plasma nitride ductile cast iron. They have concluded that brittle thin layer formed after plasma nitriding may reduce the RCF life, so that, it is necessary prevent the growing compound layer, during the plasma nitriding, when the treatment aims to rolling contact fatigue application.…”

Section: Introductionmentioning

confidence: 99%

Cast iron plasma nitriding in N2 /H2 /Ar working gas: the role of auxiliary gases (H2 /Ar) in the growing kinetics of compound layers

Fontana¹,

Sudaia²,

Recco³

et al. 2022

Tecnol. Metal. Mater. Min.

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Present paper sets out to investigate the role of N 2 /H 2 /Ar working gas in plasma nitriding of nodular cast iron. The proportion of N 2 /H 2 /Ar proved to be a relevant parameter in the growing kinetics control of the γ'-Fe 4 N e ε-Fe 3 N compound layers. X-ray diffraction and optical microscopy were used in order to characterize the compound layers. Results indicate that there are no generation of compound layers if the treatment is performed through plasma of pure N 2 . However, even small percentages (~10%) of auxiliary gases (H 2 /Ar), added to the working gas, are enough to generate compound layers as thick as 10µm (at 500 °C, and 3,0 h). In addition, it is possible to obtain γ'-Fe 4 N monophasic compound layer when the nitriding process is carried out in low proportion of nitrogen in the N 2 /H 2 /Ar working gas mixture.

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“…For white cast iron, their carbides can be better identified using a selective etching to remove deeply the matrix, as used by SINATORA et al [8] for identifying M 3 C and M 7 C 3 carbides, and by DA SILVA and BOCCALINI JR. [9] for MC and M 2 C ones. Finally, it is worthwhile to cite the investigation conducted by WOLLMANN et al [10], who used an etching for removal successive layers of ductile iron for measuring residual stresses.…”

Section: Introductionmentioning

confidence: 99%

Electrolytic polishing of compacted graphite iron for revealing subsurface graphite of honed cylinders

2019

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The superficial characteristics of honed surfaces are relevant for the tribological performance of cylinders of internal combustion engines (MCI). Recent studies found a correlation between the occurrence of the phenomenon called folded metal and the presence of graphite of cast irons. However, the honing process tends to overlap the graphite, such that an application of a technique to remove a thin layer of material, exposing the graphite, would be useful. This paper aims to determine the best condition, of electric potential and time, for the exposition of graphite in honed surfaces using a technique of electrolyte polishing. The polishing was made on the concave surface with aid of a polishing mask developed for this matter. Samples of honed cylinders were removed from MCI manufactured using a compacted graphite iron. The characterizations were done through metallography and white light interferometry. To determine the ideal condition, several conditions of polishing were tested. For the verification of the repeatability, five repetitions were performed with the best condition. The results showed satisfactory repeatability, with an exposition of graphite and the matrix etching. The roughness of the polished region presented considerable uniformity, with a significant change of roughness in comparison to the honed surface. Furthermore, removal of the characteristic topography of the honed surface was observed. The layer removed showed little variation in depth along the polished region, with values close to 5 µm. This value accomplishes the demand of layer removal for the exposition of subsurface graphite.

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Rolling Contact Fatigue Failure Mechanisms of Plasma-Nitrided Ductile Cast Iron

Cited by 8 publications

References 24 publications

Correlation between roughness, film thickness, and friction coefficient with pitting wear resistance of spur gears

Correlation between roughness, film thickness, and friction coefficient with pitting wear resistance of spur gears

Cast iron plasma nitriding in N2 /H2 /Ar working gas: the role of auxiliary gases (H2 /Ar) in the growing kinetics of compound layers

Electrolytic polishing of compacted graphite iron for revealing subsurface graphite of honed cylinders

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