Mechanical Characterization of Dual Phase Austempered Ductile Iron

Basso, Alejandro Daniel; Caldera, Martin; Chapetti, Mirco Daniel; Sikora, Jorge Antonio

doi:10.2355/isijinternational.50.302

Cited by 26 publications

(20 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Table 3 lists the upper and lower critical temperatures for each melt. As postulated in a previous work, 8) an increase in the upper and lower critical temperatures was measured as the amount of silicon increase. However, the difference between the lower and upper critical temperatures (intercritical temperature interval amplitude) remained nearly constant (80°C) for all the ductile irons evaluated in this study.…”

Section: Metallographic Characterization Of the Melts Inmentioning

confidence: 69%

“…The novelty of this DI is its mixed microstructure, which is composed of different amounts and morphologies of ausferrite (regular ADI microstructure) and free ferrite. [1][2][3][4][5][6][7][8][9][10][11][12][13] This new type of DI has awoken technological interest given the improvement in mechanical properties it has achieved in relation to conventional microstructures (ferritic, pearlitic or martensitic). As a consequence, many studies have centered their attention on assessing the mechanical properties of this new type of DI.…”

Section: Introductionmentioning

confidence: 99%

“…This stage is followed by an austempering step which transforms austenite into ausferrite. [4][5][6][7][8][9][10] As a result, a matrix with different relative percentages of free ferrite (original phase matrix) and ausferrite is obtained, depending on the intercritical austenitising temperature used. This methodology provides significant advantages over other methods: microstructures with a controlled number of phases are obtained, and thereby varied mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Development of High Silicon Dual Phase Austempered Ductile Iron

2015

Self Cite

View full text Add to dashboard Cite

This work deals with the feasibility of obtaining Austempered Ductile Iron with Dual Phase structures (DPADI) through heat treatment, starting from different as-cast microstructures. The mechanical properties on these microstructures were evaluated. DPADI microstructures were obtained by adding different tenors of silicon (2.4% to 4.2%) to the melts and keeping the other alloying elements constant. The study focused on the determination of the time required to achieve the percentages of equilibrium phases (ferrite and austenite) at different temperatures in the intercritical temperature interval as a function of the starting as cast microstructure. The results showed that, as the silicon content increases, higher amount of ferrite is present in the as cast structure, and the time required to reach the thermodynamic equilibrium phases in the intercritical temperature interval is markedly reduced. Similarly, for a constant chemical composition, as the intercritical austenitizing temperature increases, the time required to reach the quantities of the equilibrium phases decreases.Regarding mechanical properties, the tests revealed that, as expected, as intercritical austenitising temperature increases so do tensile strength and hardness due to the higher ausferrite content in the DPADI matrix.These results indicate that high silicon Ductile Iron (with Si content higher than 3%) with a mostly ferritic microstructure in as cast conditions yields DPADI microstructures able to dispense with prior annealing heat treatments since the time required to reach the phase equilibrium percentages is compatible with the industrial practice and the mechanical properties are similar as compared to DPADI structures deriving from fully ferritic matrices.

show abstract

Section: Metallographic Characterization Of the Melts Inmentioning

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Development of High Silicon Dual Phase Austempered Ductile Iron

2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…Researchers emphasized that the dual matrix ADI having considerable higher fatigue properties than as cast ductile cast irons. 42) No efforts have so far been made to optimize the fatigue properties of ADI with DMS by controlling the proeutectoid ferrite (PFVF) and ausferrite volume fraction (AFVF) by austempering from intercritical austenization temperature (ICAT) range.…”

Section: Introductionmentioning

confidence: 99%

Effect of Microstructure on Fatigue Strength of Intercritically Austenitized and Austempered Ductile Irons with Dual Matrix Structures

2013

View full text Add to dashboard Cite

In the present study the fatigue strength of austempered ductile irons with dual matrix structures (ADI with DMS) has been studied for an unalloyed ductile cast iron. For this purpose, specimens were intercritically austenitized (partially austenitized) in two phase region (α + γ ) at various temperatures (810°C, 820°C and 830°C) for 20 minutes and then quenched into salt bath held at austempering temperature of 315°C and 375°C for 120 minutes and then air cooled to room temperature to obtain various ausferrite volume fractions and their morphologies. Conventionally austempered specimens (austempered from 900°C) with fully ausferritic matrix and unalloyed as cast specimens having ferrit + pearlite structures were also tested for a comparison. Rotating bending fatigue test were carried out an the experimental results showed that, in ADI with DMS, volume fraction of ausferrite and continuity of ausferritic structure along intercellular boundaries play important role in determining fatigue strength. The fatigue strength of these specimens increases with increasing ausferrite volume fraction. The fatigue strength was correlated with the ausferrite volume fraction and high carbon austenite and its carbon content. Conventionally austempered specimens exhibited much greater fatigue strength than ADI with DMS specimens.KEY WORDS: austempered ductile iron; dual matrix structure; fatigue; ausferrite volume fraction.

show abstract

“…This improvement is explained by the novelty of this DI microstructure, which is composed of different amounts of free (or allotriomorphic) ferrite and ausferrite (ADI regular structure). [1][2][3][4][5][6][7][8][9][10][11] Special thermal cycles have been developed by different researchers in order to obtain Dual Phase ADI. One of them has been advanced and used by Kilicli et al 7,8) and Basso et al [4][5][6] It consists in subjecting fully ferritic DI parts to an incomplete austenitization stage, at different temperatures within the intercritical interval of the Fe-C-Si diagram (see Fig.…”

Section: Introduccionmentioning

confidence: 99%

High Silicon Ductile Iron: Possible Uses in the Production of Parts with ^|^ldquo;Dual Phase ADI^|^rdquo; Microstructure

et al. 2012

Self Cite

View full text Add to dashboard Cite

The aim of this paper is to study the advantages and disadvantages of using high silicon ductile iron to produce cast parts with "Dual Phase ADI" microstructure. In this study, four ductile irons with different percentages of silicon: 2.4, 3.1, 3.5, and 4.2%, respectively, were used. Samples from each cast were subjected to heat treatment in order to determine the intercritical interval. Significant increase in the upper and lower critical temperatures was found as the amount of silicon incremented. However, the difference between the lower and upper critical temperatures (intercritical interval amplitude) remained nearly constant for all ductile irons.The materials were metallographically and mechanically characterized in the as-cast conditions and after full annealing heat treatments. Tensile, hardness and impact properties were determined as a function of the silicon level.The results suggest that high silicon ductile iron (Si content ranging from 3.0 to 3.6%) can be used in the manufacture of cast parts with "Dual Phase ADI" microstructures, yielding undeniable advantages in the production process if compared to low and medium silicon ductile irons.

show abstract

Mechanical Characterization of Dual Phase Austempered Ductile Iron

Cited by 26 publications

References 7 publications

Development of High Silicon Dual Phase Austempered Ductile Iron

Development of High Silicon Dual Phase Austempered Ductile Iron

Effect of Microstructure on Fatigue Strength of Intercritically Austenitized and Austempered Ductile Irons with Dual Matrix Structures

High Silicon Ductile Iron: Possible Uses in the Production of Parts with ^|^ldquo;Dual Phase ADI^|^rdquo; Microstructure

Contact Info

Product

Resources

About