Austenitization of FerriticDuctile Iron

Krzyńska, A.; Kochański, Andrzej

doi:10.2478/afe-2014-0085

Cited by 3 publications

(3 citation statements)

References 6 publications

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“…Austempering of steel results in the formation of microstructure consisting of the acicular ferrite and iron carbide (cementite), but in the case of the austempered cast iron the microstructure consists of the high-carbon austenite and acicular ferrite [20][21][22][23][24][25][26]. It should be noted that not only the basic elements present in cast iron, but also certain alloying elements significantly influence the heat treatment process.…”

Section: Introductionmentioning

confidence: 99%

Archives of Foundry Engineering

Jakubus

2022

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The article presents the results of research on the abrasion resistance of cast iron with vermicular graphite in the as-cast state and after austempering (the latter material is referred to as AVGI -Austempered Vermicular Graphite Iron). Austenitization was carried out at the temperature values of either 900°C or 960°C, and austempering at the temperature values of either 290°C and or 390°C. Both the austenitization and the austempering time was equal to 90 minutes. The change of the pearlitic-ferritic matrix to the ausferritic one resulted in an increase in mechanical properties. Abrasion tests were conducted by means of the T-01M pin-on-disc tribometer. The counter-sample (i.e. the disc) was made of the JT6500 friction material. Each sample was subject to abrasion over a sliding distance of 4000 m. The weight losses of both samples and counter-samples were determined by the gravimetric method. It was found that the vermicular cast iron austenitized at 900°C and austempered at 290°C was characterized by the lowest wear among the evaluated cast iron types. The geometric structure of the surface layer after the dry friction test exhibited irregular noticeable grooves, distinct oriented abrasion traces, plastic flow of the material, microcracks, and pits generated by tearing out the abraded material. The largest surface roughness was found for the AVGI cast iron heat-treated according to the variant 3 (Tγ =900 ºC; Tpi = 390°C), while the smallest one occurred in AVGI cast iron subject to either the variant 2 (Tγ =960 ºC; Tpi = 290°C) or the variant 4 (Tγ =900 ºC; Tpi = 290°C) of heat treatment and was equal to either 2.5 µm or 2.66 µm, respectively. It can be seen that the surface roughness decreases with the decrease in the austempering temperature.

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Section: Introductionmentioning

confidence: 99%

Archives of Foundry Engineering

Jakubus

2022

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“…The base irons were treated with a 9.5 wt% MgFeSi alloy for spheroidisation followed by post-inoculation with 75 wt% FeSi. The material was cast in sand molds in form of Y-blocks having the dimensions of 200x150x20 mm 3 . The matrices of the as cast microstructures are comprising of ferritic and pearlitic phases as given elsewhere [9].…”

Section: Studied Materialsmentioning

confidence: 99%

“…Since the discovery of the austempered ductile iron (ADI) and its first commercialization in 1972 [1,2], many modifications in technology of heat treatment leading to cost saving and/or properties improvement were proposed [3,4]. One of these modifications is the AusformedAustempered Ductile Iron -AADI [5,6].…”

Section: Introductionmentioning

confidence: 99%

Effect of Hot Working Parameters on Microstructure Evolution and Mechanical Properties of Ausformed Austempered Ductile Iron

Soliman

Nofal

Palkowski

2018

MSF

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Abstract. Three ductile irons with different aluminum-and manganese-content were subjected to two thermo-mechanical schedules. In the first schedule, a total deformation of ϕ t = 0.3 is applied on the ductile irons in the austenitic region before the austempering process. In the second schedule, the materials are subjected to deformation of 0.2 in the austenitic region and deformation of 0.1 during austempering (ausforming). Mechanical deformation of austenite prior to the transformation "stage I" pronouncedly accelerated the transformation due to increasing the nucleation sites of ausferrite. This increase has its impact on enhancing the microstructural uniformity and refining the ausferrite platelets. On the other hand, the retained austenite content was not significantly affected by the applied ausforming. Remarkable increase in hardness, strength and ductility of the ausformed ductile iron due to the latter effects is observed.

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Prediction of Microstructure in ADI Castings

Guzik

Sokolnicki

Królikowski

et al. 2016

Archives of Metallurgy and Materials

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Tests were carried out on samples of low-alloy ductile iron with additions of Ni, Cu and Mo, subjected to austempering heat treatment. The samples were austenitized at 850, 900 and 950 °C, and then austempered at T = 210, 240, 270, 300 and 330 °C. The ausferritizing treatment was carried out in a salt bath for the time τ = 2 - 8 hours. Additionally, tests and studies covered samples subjected to the ausferritizing treatment at 270 °C with the time of holding castings in a bath from 2 to 24 hours. Evaluation covered the results of the ADI microstructure examinations and hardness measurements. The ADI matrix morphology was identified counting the average number of ausferrite plates and measuring their width and spacing. The regression equations HB = f (τ, T) and τ = f (HB, T) were derived to establish the, so-called, “process window”, allowing obtaining a priori the required microstructure of ADI and, consequently, the required mechanical properties, mainly hardness, shaping the functional properties of castings, abrasion wear resistance – in particular.

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Austenitization of FerriticDuctile Iron

Cited by 3 publications

References 6 publications

Archives of Foundry Engineering

Archives of Foundry Engineering

Effect of Hot Working Parameters on Microstructure Evolution and Mechanical Properties of Ausformed Austempered Ductile Iron

Prediction of Microstructure in ADI Castings

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