Effect of composition and heat treatment parameters on the characteristics of austempered ductile irons

Trudel, Alexandre; Gagné, M.

doi:10.1016/s0008-4433(97)00028-1

Cited by 37 publications

(28 citation statements)

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“…Austempered ductile iron with this desired ausferrite microstructure displays optimum mechanical properties. [1][2][3][4][5][6][7][8][9][10][11][12]14,15,19 The sequence of microstructural changes as a function of time observed during austempering in the present study has been described above (Figs. 5-8).…”

Section: Heat Treatments and Microstructuresmentioning

confidence: 77%

“…Major applications include gears, crankshafts, sprockets, pinions and other parts used in automotive, earth moving, excavating and agricultural equipment. 1,2 In the existing ADI literature the effect of heat-treating variables such as temperature and time of austenitising and austempering on mechanical properties is well established. [1][2][3][4][5][6][7][8][9][10][11] In the newly developed ADI with a dual matrix structure (DMS), the matrix structure consists of proeutectoid ferrite and ausferrite (bainitic ferrite and stabilised high carbon austenite) or martensite.…”

Section: Introductionmentioning

confidence: 99%

“…1,2 In the existing ADI literature the effect of heat-treating variables such as temperature and time of austenitising and austempering on mechanical properties is well established. [1][2][3][4][5][6][7][8][9][10][11] In the newly developed ADI with a dual matrix structure (DMS), the matrix structure consists of proeutectoid ferrite and ausferrite (bainitic ferrite and stabilised high carbon austenite) or martensite. [12][13][14][15][16][17][18][19][20][21][22] This microstructure is obtained by austempering or quenching from a temperature at which both ferrite and austenite are present, rapidly enough for a significant fraction of the austenite to transform to ausferrite or martensite.…”

Section: Introductionmentioning

confidence: 99%

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Effect of ausferrite volume fraction and morphology on tensile properties of partially austenitised and austempered ductile irons with dual matrix structures

Kılıçlı¹,

Erdoğan²

2007

International Journal of Cast Metals Research

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In the present study, an unalloyed ductile iron containing 3?50%C, 2?63%Si, 0?318%Mn and 0?047%Mg was intercritically austenitised (partially austenitised) in the two phase region (azc) at temperatures of 795 and 815uC for 20 min, and then was quenched into a salt bath held at an austempering temperature of 365uC for various times to obtain various ausferrite volume fractions. Fine and coarse dual matrix structures were obtained from the two different starting conditions. Some specimens were also conventionally austempered from 900uC for comparison. Results showed that a structure having proeutectoid ferrite plus ausferrite (bainitic ferritezhigh carbon retained or stabilised austenite) was developed. The phase previously described as new ferrite (also called epitaxial ferrite) was observed to form following heat treatment only in specimens with coarse austenite dispersion after austempering from the (azc) temperature range. It was observed that the parent austenite dispersion present at the intercritical austenitising temperature has an effect on the volume fraction of high carbon austenite following austempering. Finer austenite dispersions produced more stabilised high carbon austenite than coarse ones for a given austempering time. The volume fractions of proeutectoid ferrite, new ferrite, ausferrite can be controlled to influence the strength and ductility. Specimens austempered from the (azc) temperature range exhibited much greater ductility than conventionally austempered samples. Within each of the series austempered from the (azc) temperature range, the tensile strength increased and ductility decreased with increasing ausferrite volume fraction and decreasing proeutectoid ferrite volume fraction. However, specimens having a fine ausferritic structure without new ferrite exhibited lower ductility and higher strength than specimens with a coarse ausferritic structure under the same austempering conditions. The specimen with ,60% AFVF (coarse structure) and ,65% AFVF (fine structure) exhibited the best combination of high strength and ductility compared to pearlitic grades, but their ductility was slightly lower than ferritic grades. These materials satisfy the requirements for the strength of quenched and tempered grades and their ductility superior to that of this grade.

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Section: Heat Treatments and Microstructuresmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of ausferrite volume fraction and morphology on tensile properties of partially austenitised and austempered ductile irons with dual matrix structures

Kılıçlı¹,

Erdoğan²

2007

International Journal of Cast Metals Research

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“…The austempering determines the refinement of the ausferrite structure on which the mechanical properties depend. Details on the metallurgy of ADI can be found elsewhere [28].…”

Section: A Us Tempered Ductile Ironsmentioning

confidence: 99%

Ductile Iron: Fifty Years of Continuous Development

Labrecque¹,

Gagné²

1998

Canadian Metallurgical Quarterly

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The discovery of Ductile Iron in 1948 gave a new lease on life to the cast iron family. By combining the castability of gray iron and the toughness of steel, Ductile Iron compelled a wide recognition as an economical choice for high performance complex ferrous parts. Fifty years of research and developme!J.t have led to a material whose properties can be tailored for applications requiring high toughness, corrosion resistance or high tensile strength. In this paper, the state-of-the-art of Ductile Iron technology is reviewed. It is shown that, although considered as a mature technology, recent process and product developments open new avenues to this family of materials.Resume-La decouverte de la fonte G.S. en 1948 a assure un second souffle a la grande famille des fontes.Combinant la coulabilite de la fonte grise et la resistance de l'acier, la fonte G.S. est rapidement devenue un choix incontournable pour la production de composantes de forme complexe exigeant des proprietes mecaniques elevees, et ce a un cout competitif. Cinquante annees de recherche et de developpement technologique ont conduit a la creation d'une famille de materiaux pouvant satisfaire des besoins aussi diversifies que la resistance a l'impact, a la corrosion ou a l'usure. Dans cet article, la technologie de la fonte G.S. est revue et discutee. II y est demontre qu'en depit du fait que la fonte G.S. est souvent consideree comme un materiau mature, de recents developpements ouvrent de nouveaux champs d'applications a la fonte G.S.

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“…The spherical graphite cast iron should contain high amounts of alloying elements, necessary for the completion of the austempering process. Higher amounts of alloying elements increase the possibility of segregation [9,10].…”

Section: Introductionmentioning

confidence: 99%

The Effects of Austempering Heat Treatment on the Mechanical Properties of Heavy Vehicles Camshaft made of Different Analysis Ductile Cast Iron

Karaca

Şi̇mşi̇r

2019

Acta Phys. Pol. A

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The aim of this study was to investigate the effect of the austempering treatment applied on ductile graphite cast iron with different chemical composition; microstructure, hardness, tensile strength and wear resistance. For this purpose sand mold casting models of camshafts were prepared and casting simulation was carried out with the NOVACAST program. The casting quality of camshafts and production process was optimized. For nodulizing process, Fe-Si-Mg alloy has been used and Fe-Si-Ba-Ca-Al alloy has been used for inoculation process. The casting has been done 1430 • C and the pouring time in 15 s. In different analyzes, a cast camshaft subjected to a 90 min austenitizing process at 900 • C under a mill vacuum furnace. The austenitized cam shafts have been quenched into the molten salt bath (50% KNO3 + 50% NaNO3) at 260 • C temperature, held for 30, 60, 90, 120, 150, 180 and 210 min and then cooled in air. Microstructures analysis of cam shafts have been examined by optical microscope and scanning electron microscopy (SEM), mechanical tests (hardness, tensile tests and wear tests) have been performed. Results show that austempering heat treatment increases the tensile strength of cam shaft as-cast condition. In this study, the tensile strength values of the austempered structure, camshaft core which has been formed in 120 minute duration which has the combination of excellent strength and ductility, have been brought from the level of 711.08 MPa to 1424.28 MPa.

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Effect of composition and heat treatment parameters on the characteristics of austempered ductile irons

Cited by 37 publications

References 1 publication

Effect of ausferrite volume fraction and morphology on tensile properties of partially austenitised and austempered ductile irons with dual matrix structures

Effect of ausferrite volume fraction and morphology on tensile properties of partially austenitised and austempered ductile irons with dual matrix structures

Ductile Iron: Fifty Years of Continuous Development

The Effects of Austempering Heat Treatment on the Mechanical Properties of Heavy Vehicles Camshaft made of Different Analysis Ductile Cast Iron

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