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Vol.4 , No. 2, Publication Date: Mar. 23, 2018, Page: 17-30
. Ductile iron that conforms to ASTM A536 65-45-12 grade was produced, cast into Y-block, machined into section thicknesses ranging from 5 to 25 mm, and isothermally heat treated at 300°C and 375°C austempering temperatures to produce ADI. Thereafter, the microstructure and mechanical properties were characterized. The microstructures were characterized using Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) method. Their strength and hardness were also evaluated in accordance with ASTM standard procedures. The microstructure revealed significant coarsening of ausferrite as the section thickness increases with 375°C austempering temperature coarser. The mechanical test results indicated that strengths and hardness value decreases with increase in section thickness while the percentage elongation and impact strength increases with it. The study concluded that the structure and mechanical properties of ADI strongly depends on the castings dimensions.&picture=http://www.aascit.org/aascit/decorators/img/journal/891.jpg)
| [1] | John Oluyemi Olawale, Department of Material Science and Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria. |
| [2] | Simeon Ademola Ibitoye, Department of Material Science and Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria. |
| [3] | Kunle Michael Oluwasegun, Department of Material Science and Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria. |
This study aimed at evaluating the effects of castings dimensions on the microstructure and mechanical properties of austempered ductile iron (ADI). Ductile iron that conforms to ASTM A536 65-45-12 grade was produced, cast into Y-block, machined into section thicknesses ranging from 5 to 25 mm, and isothermally heat treated at 300°C and 375°C austempering temperatures to produce ADI. Thereafter, the microstructure and mechanical properties were characterized. The microstructures were characterized using Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) method. Their strength and hardness were also evaluated in accordance with ASTM standard procedures. The microstructure revealed significant coarsening of ausferrite as the section thickness increases with 375°C austempering temperature coarser. The mechanical test results indicated that strengths and hardness value decreases with increase in section thickness while the percentage elongation and impact strength increases with it. The study concluded that the structure and mechanical properties of ADI strongly depends on the castings dimensions.
Keywords
Ductile Iron, Austempered Ductile Iron, Ausferrite, Austempering Temperature, Section Thickness
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