Machinability and related properties of austempered ductile iron: A review

Hegde, Ananda; Sharma, Sathyashankara; C, Gowri Shankar M.

doi:10.15282/jmes.12.4.2018.14.0360

Cited by 8 publications

(2 citation statements)

References 38 publications

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“…Austempered ductile irons (ADIs) are advanced spheroidal irons produced through heat-treating conventional ductile irons (DIs), resulting in a dual phase acicular microstructure called ausferrite, consisting of hard bainitic ferrite α and metastable high C content austenite γ HC [1][2][3][4][5][6][7][8]. Ausferrite has an excellent combination of strength, ductility [9][10][11][12][13] and other mechanical properties, such as fatigue and fracture resistance [14][15][16][17][18][19][20][21][22][23]. Their properties are similar to cast and wrought steels, with which they can compete as materials for applications in components for heavy transportation, such as trucks, earth-moving machinery and the train industry [24][25][26][27], thanks also to their production cost that is about 50% less than the cost of steels and their density that is about 10-12% lower [7,28,29].…”

Section: Introductionmentioning

confidence: 99%

On Ausferrite Produced in Thin Sections: Stability Assessment through Round and Flat Tensile Specimen Testing

Angella

Donnini

Ripamonti

et al. 2023

Metals

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Ductile irons were produced into different casting wall sections, that is, 25 mm, 5 mm and 3 mm. The alloys were then austenitized with the same conditions at 875 °C for 2 h and austempered for three different combinations of temperatures and times: 250 °C for 6 h, 310 °C for 3 h and 380 °C for 1 h. The aim of the investigation was to study the ausferrite stability of austempered ductile irons with three different nominal contents of nickel produced in thin sections through tensile testing. So, strain hardening analysis of tensile flow curves was carried out since it has been found to be a reliable support to ductility analysis in assessing the optimal austempering conditions. Because of different wall sections, round and flat tensile specimens with geometries complying with ASTM E8/E8M-11 were tested. Austempered ductile irons from 5 and 3 mm wall sections were tested through flat geometry specimens only, while 25 mm wall sections were tested through both round and flat geometries. Though the ausferrite was affected by Ni content and the graphite morphology was improved with reduced thin sections, the ausferrite stability and the tensile mechanical behavior were insensitive to Ni content and section thickness below 25 mm. Furthermore, it resulted that the tensile plastic behavior was sensitive to the specimen geometry in a consistent way, increasing the instability of ausferrite and indicating that a proper analysis and comparison of tensile properties of austempered ductile irons must take into account the tensile specimen geometry.

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Section: Introductionmentioning

confidence: 99%

On Ausferrite Produced in Thin Sections: Stability Assessment through Round and Flat Tensile Specimen Testing

Angella

Donnini

Ripamonti

et al. 2023

Metals

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“…Different scientists have examined the phase transformation and mechanical characteristics of graphite cast iron materials, and articles have been published that outline their performances in engineering service environments [ 13 , 19 , 20 ]. Nevertheless, there are still gaps in the information regarding the morphological structures, processing techniques, phase analysis, and overall mechanical behavior, which are discussed in this paper.…”

Section: Introductionmentioning

confidence: 99%

A Review on Heat Treatment of Cast Iron: Phase Evolution and Mechanical Characterization

et al. 2022

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The isothermal heat treatment process has been identified as a unique process of fabricating exceptional graphite cast iron due to its remarkable mechanical properties, such as excellent machinability, toughness, and high level of ultimate tensile strength. Austempered ductile iron (ADI), ductile iron (DI), and gray cast iron (GCI), known as spheroidal cast irons, are viable alternative materials compared to traditional steel casting, as well as aluminum casting. The graphite nodules from the microstructures of DI, ADI, and GCI are consistently encompassed by acicular ferrite and carbon-saturated austenite in the matrix, forming a distinctive ausferritic structure. All these materials are extensively used in the fabrication of engine sleeves, engine blocks, valves, gears, and camshafts in the automobile sector. With relative motion and outward loads, these components are regularly exposed to surface contact. In this project, it was observed that austempering temperature and a shorter holding period could also be used to manufacture needle-like ferrite platelets for austempered ductile iron (ADI) and other graphite cast irons. To overcome the brittleness challenges and catastrophic failures encountered by applied loads in present-day applications, it is essential to comprehend the isothermal treatments, morphological behaviors, phase analyses, processing techniques, and mechanical properties needed to properly incorporate these materials into future designs. This review article provides detailed information on the characterization and relevant potential mechanisms of ADI, DI, and GCI.

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Structural stability of thin-walled austempered ductile iron castings

Górny

Gondek

Angella

et al. 2023

Archiv.Civ.Mech.Eng

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The structural stability of ausferrite in thin-walled Austempered Ductile Iron (ADI) castings with 5 mm wall thickness is compared to a reference casting with 25 mm wall thickness. The thin-walled and reference castings were first austenitized between 850 and 925 °C, and then austempered between 250 and 380 °C. X-ray diffraction (XRD) investigations with changing temperature were performed between − 260 up to + 450 °C to investigate the change of phase fraction, lattice parameters and strain in ausferrite. The role of the austenitization temperature on structural stability and homogeneity of the investigated ADI castings has been provided. In addition, the problem of the occurrence of “blocky” high-carbon austenite that was not completely involved during austempering, has been taken into account. Finally, it has been shown that the thin-walled castings provided higher structural homogeneity and stability if compared to the reference castings.

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Machinability and related properties of austempered ductile iron: A review

Cited by 8 publications

References 38 publications

On Ausferrite Produced in Thin Sections: Stability Assessment through Round and Flat Tensile Specimen Testing

On Ausferrite Produced in Thin Sections: Stability Assessment through Round and Flat Tensile Specimen Testing

A Review on Heat Treatment of Cast Iron: Phase Evolution and Mechanical Characterization

Structural stability of thin-walled austempered ductile iron castings

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