IMPACT TOUGHNESS OP AUSTEMPERED DUCTILE CAST IRON | ||||
The International Conference on Applied Mechanics and Mechanical Engineering | ||||
Article 40, Volume 2, 2nd Conference on Applied Mechanical Engineering., May 1986, Page 171-180 PDF (2.68 MB) | ||||
Document Type: Original Article | ||||
DOI: 10.21608/amme.1986.57076 | ||||
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Authors | ||||
H. Abu-Elfotouh1; O. A. Abu-Zeid2; B. A. Elsarnagawy1; A. M. Eleiche3 | ||||
1Dept. of Metallurgy,Military Technical College,Cairo,Egypt. | ||||
2Dept. of Mech. Design and Prod.,Cairo University,Egypt. | ||||
3On leave to Dept. of Engineering,The American University in Cairo, Egypt. | ||||
Abstract | ||||
The influence of austempering temperature and time, as main austempering control parameters, on the impact toughness and microstructure of a ductile cast iron alloy having a carbon equivalent of 3.88 percent has been investigated. Two transformation temperatures were chosen at 270°C and 400°C such as to obtain microstructure falling within the zones of lower and upper bainite, respectively. Austempering time intervals ranging from 5 minutes to 5 hours were selected for each austempering temperature. Peak values of U-notch Charpy impact toughness of 7.55 and 17.23 Joule/cm² have been attained at time interval of 60 minutes for specimens austempered at 270°C and 400°C, respectively. The changes in mechanical properties with the transformation temperature and time has been observed to be directly related to the phase transformations in the micro-structure. The study of fracture surfaces of impact toughness samples revealed the great complexity of the crack propagation process in austempered ductile iron due to the nature of its structure. | ||||
Keywords | ||||
Austempered ductile iron; micro-structure; upper bainite; lower bainite; Mechanical Properties | ||||
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