Development of austempered ductile cast iron (ADI) with simultaneous high yield strength and fracture toughness by a novel two-step austempering process

Putatunda, Susil K.

doi:10.1016/s0921-5093(01)01210-2

Cited by 170 publications

(83 citation statements)

References 13 publications

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“…This is called primary reaction (or stage I) when austenite (γ) changes into carbon-stabilized austenite (γ hc ) and ferrite (α). If the primary reaction takes place for more time, then a secondary reaction (stage II) starts, wherein γ hc changes into brittle carbide and ferrite, thus bringing down the properties of castings [6].…”

Section: Introductionmentioning

confidence: 99%

Austempered Ductile Iron (ADI): Influence of Austempering Temperature on Microstructure, Mechanical and Wear Properties and Energy Consumption

Sellamuthu

Samuel

Dinakaran

et al. 2018

Metals

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Alloyed Ductile iron, austenitized at 840 • C for 30 min in a special sealed austempering furnace, was austempered for 30 min in molten salt mixture at 4 trial temperatures of 300 • C, 320 • C, 340 • C and 360 • C. Tensile strength, yield strength, percentage elongation and impact energy were evaluated for the as-cast and austempered samples. Microstructures were investigated using microscopy, coupled with analyzing software and a scanning electron microscopy. The specific wear of samples was tested using pin-on-disc wear testing machine. X-ray diffraction was performed to calculate the amount of retained austenite present in the ausferrite matrix. As-cast microstructure consists of ferrite and pearlite, whereas austempered ductile iron (ADI) contains a mixture of acicular ferrite and carbon enriched austenite, called "ausferrite". Hardness and strength decreased, whereas ductility and impact strength improved with an increase in the austempering temperature. XRD analysis revealed that the increase in austempering temperature increased the retained austenite content. A decrease in wear resistance with austempering temperature was observed. Modified Quality Index (MQI) values were envisaged, incorporating tensile strength, elongation and wear resistance. MQI for samples austempered at 340 • C and 360 • C showed a better combination of properties. About an 8% reduction in energy consumption was gained when the heat treatment parameters were optimized.

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Section: Introductionmentioning

confidence: 99%

Austempered Ductile Iron (ADI): Influence of Austempering Temperature on Microstructure, Mechanical and Wear Properties and Energy Consumption

Sellamuthu

Samuel

Dinakaran

et al. 2018

Metals

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“…A maior quantidade de nódulos e o maior tamanho médio de grafita (Tabela 2) levam a baixos valores de energia absorvida, pois existe menor distância relativa entre os nódulos, favorecendo o coalescimento dos alvéolos e diminuindo a resistência a propagação da trinca (Putatunda, 2001).…”

Section: Tabela 4: Resultados Do Ensaio De Impacto Em Corpos-de-provaunclassified

Estudo comparativo de ferros fundidos nodulares temperados e austemperados

Cardoso¹,

Israel²,

Strohaecker³

2010

ete

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“…This complex type of ADI heat treatment has a rich bibliography [19][20][21][22][23][24][25][26][27][28]. The opinion that complex heat treatment does enable better mechanical properties, both R m and A, than those achieved due to standard one-step austempering is established.…”

Section: Introductionmentioning

confidence: 99%

Optimization of mechanical properties of complex, two-stage heat treatment of Cu–Ni (Mn, Mo) austempered ductile iron

Gazda

Warmuzek

Bitka

2018

J Therm Anal Calorim

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The aim of the study was to design and optimize the complex, two-step heat treatment of Cu-Ni (Mn, Mo) ductile iron. A method for the formation and investigation of austempered ductile iron (ADI) by means of complex two-step and as comparative, standard one-step heat treatments has been developed, using quenching dilatometer. Investigations of proceeding phase transformations using differential dilatometric and DSC analysis supported by microstructural observations, hardness and austenite volume measurements have been carried out. An analysis of the temperature sequence of the ausferrite decomposition in the one-step and two-step ADI was performed, which allowed for the separation and identification of the effects responsible for the carbon-enriched austenite decomposition. A quantitative relationship was established between basic dimensional effects revealed on the differential dilatometric curve of ausferrite decomposition, which enables prognosis and optimization of the parameters of complex ADI heat treatment variants. Verification tests were performed on a stand equipped with salt furnaces enabling a quick transfer of samples from one bath to another without changing their initial temperature. Optimization of the two-step ADI heat treatment with the use of quantitative dilatometric analysis of the ausferrite decomposition, allowed to obtain for the temperature step-down heat treatment 390°C/15, 20 min ) 270°C/130 min the excellent mechanical properties, unattainable by means of standard 1-step ADI heat treatment.

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Development of austempered ductile cast iron (ADI) with simultaneous high yield strength and fracture toughness by a novel two-step austempering process

Cited by 170 publications

References 13 publications

Austempered Ductile Iron (ADI): Influence of Austempering Temperature on Microstructure, Mechanical and Wear Properties and Energy Consumption

Austempered Ductile Iron (ADI): Influence of Austempering Temperature on Microstructure, Mechanical and Wear Properties and Energy Consumption

Estudo comparativo de ferros fundidos nodulares temperados e austemperados

Optimization of mechanical properties of complex, two-stage heat treatment of Cu–Ni (Mn, Mo) austempered ductile iron

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