Intercritically Austenitized Quenched and Tempered Ductile Iron
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Ductile iron with a matrix of ferrite plus martensite was produced using a ductile iron alloyed with ∼0.7 wt% manganese and ∼0.5 wt% nickel. Three different volume percentages of martensite (16, 24 and 37 vol %) were formed by austenitizing in the intercritical region (ferrite + austenite) followed by quenching in a polymeric solution to room temperature. The materials were evaluated in the untempered condition and after tempering at 400C (752F) and 500C (932F) for one hour. This paper reports the effects of volume percent martensite and tempering conditions on microstructure and tensile properties. Semi-quantitative chemistry and microhardness of ferrite and martensite were also determined as a function of martensite volume percent. The results indicated that the carbon available to form the austenite during intercritical austenitizing came mainly from the carbon in the matrix and that partitioning of substitutional elements is limited. The results also showed that ultimate and yield strength and hardness increased and elongation decreased as the volume fraction of martensite increased. Tempering significantly increased the elongation with only a small decrease in the strengths.
Keywordsintercritical austenitizing tempering ductile iron dual phase
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- 1.Sorelmetal, “The Sorelmetal Book of Ductile Iron,” vol. 1, pp. 123–30, Rio Tinto Iron and Titanium, Québec, Canada (2004).Google Scholar
- 2.Rundman, K.B., “Heat Treating of Ductile Irons,” ASM Handbook Volume 04: Heat Treating, ASM International, pp. 682–692 (1991).Google Scholar
- 5.Aristizabal, R.E., Druschitz, A.P., Druschitz, E., Bragg, R., Hubbard, C.R., Watkins, T.R., Ostrander, M., “Intercritically Austempered Ductile Iron,” AFS Transactions, vol. 119, pp. 407–413 (2011).Google Scholar
- 13.Valdés, C., Pérez, M.J., Figueroa, M., Ramírez, L.E., “Austempered Ductile Irons with Dual Phase Matrix Structures,” Revista Mexicana de Fisica, vol. 55, pp. 48–51 (2009).Google Scholar
- 14.Erdogan, M., Kilicli, V., Demir, B., “Transformation Characteristics of Ductile Iron Austempered from Intercritical Austenitizing Temperature Ranges,” Journal of Materials Science and Engineering, vol. 44, pp. 1394–1403 (2009).Google Scholar
- 18.Cerah, M., Kocatepe K., Erdogan, M., “Influence of Martensite Volume Faction and Tempering Time on the Tensile Properties of Partially Austenitized in the (α+γ) Temperature Range and Quenched + Tempered Ferritic Ductile Iron,” Journal of Materials Science, vol. 40, pp. 3453–3459 (2005).CrossRefGoogle Scholar
- 19.ASTM International, “ASTM E8-04 Standard Test Methods for Tension Testing of Metallic Materials,” Annual Book of ASTM Standards, vol. 3.01, pp. 62–85 (2005).Google Scholar
- 22.Jenkins, L.R., Forrest, R.D., “Ductile Iron” ASM Handbook, Volume 01: Properties and Selection: Irons, Steels, and High-Performance Alloys, pp. 33–55 (1990).Google Scholar