The austempering study of alloyed ductile iron

Erić, Olivera; Jovanović, M.; ̄anin, Leposava Šid; Rajnović, Dragan; Zec, S.

doi:10.1016/j.matdes.2004.11.028

Cited by 51 publications

(30 citation statements)

References 2 publications

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“…Nickel, copper, and molybdenum are by far the most widely used alloying elements in both conventional and austempered ductile irons [5,8,[14][15][16][17][18][19][20][21][22][23][24][25]. Ni and Cu are austenite stabilizers with low affinity towards carbon.…”

Section: Introductionmentioning

confidence: 99%

Effects of Alloying Elements (Mo, Ni, and Cu) on the Austemperability of GGG-60 Ductile Cast Iron

Konca

Tur

Koç

2017

Metals

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Abstract:The interest in austempered ductile irons (ADI) is continuously increasing due to their various advantageous properties over conventional ductile irons and some steels. This study aimed to determine the roles of alloying elements Ni, Cu, and Mo, on the austemperability of GGG-60 ductile cast iron. Two different sets of GGG-60 (EN-GJS-600-3) samples, one set alloyed with Ni and Cu and the other set alloyed with Mo, Ni, and Cu, were subjected to austempering treatments at 290 • C, 320 • C, and 350 • C. A custom design heat treatment setup, consisting of two units with the top unit (furnace) serving for austenitizing and the 200 L capacity bottom unit (stirred NaNO 2 -KNO 3 salt bath) serving for isothermal treatment, was used for the experiments. It was found that austempering treatment at 290 • C increased the hardness of the Ni-Cu alloyed GGG-60 sample by about 44% without causing a loss in its ductility. In the case of the Mo-Ni-Cu alloyed sample, the increase in hardness due to austempering reached to almost 80% at the same temperature while some ductility was lost. Here, the microstructural investigation and mechanical testing results of the austempered samples are presented and the role of alloying elements (Mo, Ni, and Cu) on the austemperability of GGG-60 is discussed.

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Section: Introductionmentioning

confidence: 99%

Effects of Alloying Elements (Mo, Ni, and Cu) on the Austemperability of GGG-60 Ductile Cast Iron

Konca

Tur

Koç

2017

Metals

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“…The austempering time was 2 h in case of DI alloyed with Cu and 3 h for DI alloyed with Cu and Ni. Austempering temperature and time were chosen on the basis of data from earlier research (Eric et al , 2005; Eric, Jovanovic et al , 2006) in order to achieve the highest content of retained austenite and hence the highest ductility.…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

Transition temperature and fracture mode of as‐castand austempered ductile iron

Rajnović

Erić²,

Šidjanin

2008

Journal of Microscopy

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SummaryThe ductile to brittle transition temperature is a very important criterion that is used for selection of materials in some applications, especially in low-temperature conditions. For that reason, in this paper transition temperature of as-cast and austempered copper and copper-nickel alloyed ductile iron (DI) in the temperature interval from −196 to +150• C have been investigated. The microstructures of DIs and ADIs were examined by light microscope, whereas the fractured surfaces were observed by scanning electron microscope. The ADI materials have higher impact energies compared with DIs in an as−cast condition. In addition, the transition curves for ADIs are shifted towards lower temperatures. The fracture mode of Dls is influenced by a dominantly pearlitic matrix, exhibiting mostly brittle fracture through all temperatures of testing. By contrast, with decrease of temperature, the fracture mode for ADI materials changes gradually from fully ductile to fully brittle.

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“…The research on ADI is focused on the modification of matrix microstructure through heat treatment or alloying elements additions . According to different requirements of the application, the microstructure can be modified by controlling the austenite and austempered process .…”

Section: Introductionmentioning

confidence: 99%

Influence of Graphite Nodules on the Microstructure and Mechanical Properties of Hollow Ductile Iron Pipe after Austempering Treatment

Wang

Gao

et al. 2019

steel research int.

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Herein, the microstructure and mechanical properties of ductile iron with different numbers of graphite nodules before and after austempering treatment are systematically investigated. The results show that the amounts of graphite nodules affect the microstructure and resulting mechanical properties of ductile iron. The ferrite fraction in an as-cast matrix decreases with the increase in graphite nodules; this outcome is mainly attributed to the cooling rate. The matrix of ductile iron after austempering treatment is composed of acicular ferrite and retained austenite. The acicular ferrite is refined with the increase in graphite nodules, because the increase in interface between graphite/austenite provides more nucleation sites during austempering treatment. Meanwhile, the formation of ferrite causes carbon atoms to diffuse into the surrounding matrix, giving rise to the increase in carbon concentration of untransformed austenite and further stabilizing the retained austenite. Hence, the volume fraction of retained austenite and the carbon content in it both increase with the increase in graphite nodules. The amounts in graphite nodules affect the mechanical properties significantly after austempering treatment; this outcome is related to the phase constituents of ductile iron after austempering treatment. Herein, the detailed mechanisms are discussed.

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The austempering study of alloyed ductile iron

Cited by 51 publications

References 2 publications

Effects of Alloying Elements (Mo, Ni, and Cu) on the Austemperability of GGG-60 Ductile Cast Iron

Effects of Alloying Elements (Mo, Ni, and Cu) on the Austemperability of GGG-60 Ductile Cast Iron

Transition temperature and fracture mode of as‐castand austempered ductile iron

Influence of Graphite Nodules on the Microstructure and Mechanical Properties of Hollow Ductile Iron Pipe after Austempering Treatment

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