Influence of Semi-Solid Isothermal Heat Treatment on Microstructure and Mechanical Properties of Ductile Cast Iron

Copyright © 2014 Mohamed Ramadan, Naglaa Fathy. This is an open access article distributed under the Creative Commons Attri-bution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In accordance of the Creative Commons Attribution License all Copyrights © 2014 are reserved for SCIRP and the owner of the intellectual property Mohamed Ramadan, Naglaa Fathy. All Copyright © 2014 are guarded by law and by SCIRP as a guardian. In this research, the effect of semi-solid isothermal heat treatment on microstructure, hardness and impact toughness of ductile iron (DI) is studied. Heat-treated air-cooled ductile iron shows spheroid graphite, cementite and fine pearlite matrix structure. At the early stages of heating time (up to 20 min), the DIs show significant decrease in amounts of graphite and significant increase in amounts of cementite. By increasing heating time, above 20 min, the DIs show slightly decrease in amounts of graphite and slightly increase in amounts of cemen-tite. Hardness values increase by increasing heating time. Meanwhile, the impact toughness decrease with in-creasing heating time. The optimum heating treatment condition for reasonable structure and mechanical prop-erties could be achieved at the temperature of 1165˚C for the heating time range of 10 to 15 min