The Effect of Heat Treatment Parameters on Microstructure and Toughness of Austempered Ductile Iron (ADI)

Abstract:

In this investigation, the effect of heat treatment parameters on the microstructure and impact energy as a measure of toughness of the austempered ductile cast iron (ADI) was studied. Yblocks were casted from ductile cast iron with following composition: 3.2% C, 2.5% Si, 1.09% Ni, 0.87% Cu, 0.5% Mo and 0.16%Mn. Charpy specimens (un-notched) were machined from the straight part of Y-blocks. All of specimens were heat treated with different conditions. Some of them were austenitized at 900°C for 60 min and then austempered at 250, 300, 350 and 400°C for various durations. Then, hardness test, impact test, optical microscopy and X-ray diffraction (XRD) were performed on the heat treated ductile iron samples. The results reveal the highest impact energy (105 J) for the sample austenitized at 900°C and austempered at 350°C for 150 min. The microstructure of this sample consisted of 28% austenite and broad ferrite needles.

• Periodical: Advanced Materials Research (Volumes 264-265)
• Pages: 409-414
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.264-265.409
• Online since: June 2011
• Authors: Amir Abedi, S.P.H. Marashi, K. Sohrabi, M. Marvastian, S.M.H. Mirbagheri
• Keywords: Austempered Ductile Cast Iron, Austempering, Impact Energy, Retained Austenite

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