الفهرس 
ABSTRACTOnly 14 pages are availabe for public view
 |  | from | 147 |  |  |
| | | from | 147 | | |
Abstract
This study presents the results obtained and deductions made from a
series of microstructural investigations, mechanical tests, and wear resistance of cast iron specimens. These investigations were performed on grey cast iron specimens that were sand cast with different cooling rates by changing the bars diameters to be 22, 25, 30, 35 and 40 mm. In addition, ductile cast iron was also sand cast with adding different amount of ferrosilicon magnesium (Mg) alloy namely; 0, 0.4, 0.8, 1.2 and 1.6 wt.% of the total charge. The effect of both the cooling rates and ferrosilicon magnesium (Mg) additions on the graphite aspect ratio, ultimate tensile strength (UTS), elongation, hardness, and wear resistance were evaluated. Microstructural changes with various cooling
rates and Mg additions, to cast iron ingots, were delineated and
explained using the optical microscopy (OM). Furthermore, dry sliding
wear tests have been performed on a designed pin-on-disc apparatus.
The experimental results of this work show that the UTS and elongation
are highly dependent on the cooling rates and Mg additions that in turn
determine the graphite aspect ratio in cast iron alloys.
Attempts were also made, in this work, to explain these effects and to
correlate the UTS and elongation with the graphite aspect ratio.
Moreover, it was found that UTS and wear resistance increase as
cooling rates increase. As Mg alloy additions increases the UTS
increases but wear resistance decreases.