Effect of graphite morphology on decarburized cast iron

Yamaguchi, Yasufumi; Kiguchi, Shoji; Sumimoto, Haruyoshi; Nakamura, K.

doi:10.1080/13640461.2003.11819572

Cited by 11 publications

(8 citation statements)

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“…The maximum temperature of ferritic SGI in service is limited by three phenomena: the ferriteaustenite phase transition which leads to dimensional changes [5], decarburization which increases with temperatures above 800 °C [5] but shows little variation with Si-content [5,6], and oxidation. On Fe-Si alloys and SiMo SGI, oxidation usually proceeds in two steps.…”

Section: Introductionmentioning

confidence: 99%

High-Temperature Oxidation of a High Silicon SiMo Spheroidal Cast Iron in Air with In Situ Change in H2O Content

Ebel

Brou

Malard

et al. 2018

MSF

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Exhaust manifolds for diesel engines are made of high-Si ferritic nodular cast irons. It is experimentally well established that their oxidation kinetics are highly sensitive to the presence of water vapor, though the mechanism for such an effect is still controversial. In the present work, isothermal oxidation tests were performed on a SiMo nodular cast iron at 700°C and 800°C in dry and humid air for 25 and 50 hours. Other samples were oxidized for 50 h with in-situ change in H2O content after 25 h, switching from dry air to humid air or the other way round. Samples were then analyzed using XRD, SEM-EDS and Raman spectroscopy. Thermogravimetric records clearly showed the effect of temperature and environment on oxidation and decarburization. The kinetics of these phenomena depends on silica formation at the metal-oxide interface. At both temperatures, water vapor was seen to promote internal oxidation of Si instead of its external oxidation. This leads to higher oxidation kinetics at 700°C and higher decarburization kinetics at 800°C.

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Section: Introductionmentioning

confidence: 99%

High-Temperature Oxidation of a High Silicon SiMo Spheroidal Cast Iron in Air with In Situ Change in H2O Content

Ebel

Brou

Malard

et al. 2018

MSF

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“…Different from the oxidation behavior of SiMo1000, no deep decarburization zone is found in SiMo51 as can be seen from Fig.12a showing the cross-section of the 160h test sample in exhaust atmosphere. The difference is due to different graphite morphology [12], decarburization is much more severe in lamellar-graphite iron than in spheroidal type. In Fig.12b, at higher magnification, it is found that the surface graphite is oxidized first, releasing the surface carbon from the material.…”

Section: Oxidation Test Resultsmentioning

confidence: 96%

High-Temperature Corrosion-Fatigue Behavior of Ductile Cast Irons for Exhaust Manifolds Applications

Xiang

Zhu

Jönsson

2018

MSF

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In the present study, low-cycle fatigue (LCF) tests and oxidation tests in controlled atmospheres are carried out at 800°C on two ductile cast irons SiMo51 and SiMo1000. The LCF tests are carried out in argon and synthetic exhaust gas, whereas oxidation tests are carried out in the latter atmosphere. S-N curves and weight-gain curves are presented. The crack growth mechanisms and oxidation mechanisms are investigated, as well as the synergetic effects. A surprising finding of increased fatigue resistance in oxidizing atmosphere is partly explained.

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“…Thenceforth, the ferritizing process dissolves those carbides to produce, for the highest values of the tempering parameter, a fully ferritic microstructure. Furthermore, decarburization also takes place and nodular and compacted graphite disappear from the outer layers of the samples, leaving footprints [31] that can be seen clearly in Figure 8f. Although Figure 8 shows the evolution of the harder group of samples, the microstructure of the other groups follow a similar evolution once the decomposition of the microstructure has begun.…”

Section: Microstructure Evolutionmentioning

confidence: 97%

Hardness Prediction in Quenched and Tempered Nodular Cast Iron Using the Hollomon-Jaffe Parameter

Vicente

Carrasco

Antoni

et al. 2021

Metals

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The Hollomon-Jaffe parameter is usually used to stablish a equivalence between time and temperature in a tempering treatment, but not to predict the harness of the alloy after the treatment. In this paper this last possibility has been studied. A group of cast iron samples was annealed and cooled at different rates in order to obtain samples with three different hardness values. These samples were tempered using different times and temperatures. The Hollomon-Jaffe parameter was calculated for each case and a relationship based on a logistic function between that parameter and the final hardness was stablished. This relationship was found to depend on the initial hardness and the lowest hardness achievable.

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Effect of graphite morphology on decarburized cast iron

Cited by 11 publications

References 0 publications

High-Temperature Oxidation of a High Silicon SiMo Spheroidal Cast Iron in Air with <i>In Situ</i> Change in H<sub>2</sub>O Content

High-Temperature Oxidation of a High Silicon SiMo Spheroidal Cast Iron in Air with <i>In Situ</i> Change in H<sub>2</sub>O Content

High-Temperature Corrosion-Fatigue Behavior of Ductile Cast Irons for Exhaust Manifolds Applications

Hardness Prediction in Quenched and Tempered Nodular Cast Iron Using the Hollomon-Jaffe Parameter

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