The effect of reducing the austempering time on the fatigue properties of austempered ductile iron

Dias, José Felipe; Ribeiro, Gabriel O; Carmo, Denilson José do; Vilela, Jefferson José

doi:10.1016/j.msea.2012.07.005

Cited by 14 publications

(6 citation statements)

References 10 publications

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“…Besides austempering temperature, the choice of austempering time could also influence material properties in ferrous metals. Studies have shown that increase in austempering time have led to improvements in properties like fatigue life, tensile strength, elongation, impact strength and yield strength while hardness of the ferrous metals studied have decreased with increase in austempering time (Akor & Tuleun, 2014;Felipe Dias, Ribeiro, Carmo, & Vilela, 2012;Han et al, 2012). Akor and Tuleun, (2014) observed austempered ductile iron specimens at different austempering time of 1, 2, 3, 4 and 5hrs over same austenitizing temperature of 950 o C and recorded increases in yield strength, tensile strength, elongation and impact energy (Akor & Tuleun, 2014).…”

Section: *Corresponding Authormentioning

confidence: 99%

“…While evaluating the effects of austempering time on the property (fatigue) of ductile iron, Felipe Dias et al, 2012 noticed that reducing austempering time also led to increase in fatigue life (Felipe Dias et al, 2012). 50 minutes have been chosen for the isothermal transformation of test specimen during the austempering process in this study.…”

Section: *Corresponding Authormentioning

confidence: 99%

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Microstructure and Mechanical Characterization of Austempered AISI 1018 Steel

Bodude¹,

Adigun²,

Ibrahim³

2020

FUOYEJET

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AISI 1018 mild steels are widely used for engineering applications in machine components and for structural purposes. These materials suffer mechanical damages especially when used under critical conditions of extreme load. In this study, the effect of austempering heat-treatment on the hardness, tensile strength, impact energy and the microstructure of AISI 1018 steels were evaluated. The steel specimens were subjected to austempering heat-treatment by austenitizing at a temperature of 830°C, maintained at this temperature for a period of 1 hour 30 minutes, before rapidly cooled down in a NaNO3 salt bath maintained at 300°C for isothermal transformation for a further 50 minutes before finally cooled down to room temperature. Microstructural analysis using Scanning Electron Microscope (SEM) shows transformation from ferrite/pearlite to bainite microstructure. The tensile strengths of the specimen increased from 400 MPa to 500 Mpa; hardness increased from an average value of 140Rc to 162Rc; while impact energy increased from 15.6 Joule to 30.6 Joule by the austempering heat-treatment. Keywords—Austempering, hardness, tensile strength, impact energy, microstructure

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Section: *Corresponding Authormentioning

confidence: 99%

Section: *Corresponding Authormentioning

confidence: 99%

Microstructure and Mechanical Characterization of Austempered AISI 1018 Steel

Bodude¹,

Adigun²,

Ibrahim³

2020

FUOYEJET

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“…In the case of too long duration of austempering lower hardness, strength, fracture toughness and ductility exhibits. At the temperature of 330 °C more than half an hour is enough to reach necessary structure, while lowest process temperature 270 °C requires more than 1 h [7,9,10].…”

Section: Fig 1 Schematic Illustration Of Heat Treatment Cycle Of Nementioning

confidence: 99%

Research on Tensile Behaviour of New Structural Material MoNiCa

Bahdanovich¹,

Bendikienė²,

Česnavičius³

et al. 2019

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This article presents the results of a set of innovative research to analyse a new structural material – steel like austempered ductile cast iron with mechanical properties similar to heat-treated steel, and with technological and exploitation characteristic close to high-strength cast iron with nodular graphite. Specific examples of its high efficiency for the manufacture of critical, mass and heavy-loaded components of modern machinery and equipment are presented. New structural material MoNiCa was tested on tension and was compared to commercial grades of austempered ductile cast irons and heat treated steels. Unconventional behaviour of examined material was observed: with tensile strength increase to almost 1600 MPa the metal became less brittle. Hardness test revealed another distinctive feature of new material that there is no linear relation between strength and hardness increase, different hardness values ~ 40 HRC or ~ 55 HRC can be achieved with the same tensile strength 1000 – 1200 MPa. Microscopic analysis demonstrated of sophisticated structure formed owing to different regimes of austempering treatment. Specific properties emerged from successful ratio of three elements Mo, Ni, and Cu (carbon equivalent), and properly chosen heat treatment modes. DOI: http://dx.doi.org/10.5755/j01.ms.25.3.23079

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“…According to different requirements of the application, the microstructure can be modified by controlling the austenite and austempered process . For example, reducing the austempered time of ductile iron was beneficial for the improvement in fatigue properties . In addition, the addition of alloying elements, such as Cu, Mo, Ni, and Mn, had a significant impact on the microstructure of ADI .…”

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 effect of reducing the austempering time on the fatigue properties of austempered ductile iron

Cited by 14 publications

References 10 publications

Microstructure and Mechanical Characterization of Austempered AISI 1018 Steel

Microstructure and Mechanical Characterization of Austempered AISI 1018 Steel

Research on Tensile Behaviour of New Structural Material MoNiCa

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

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