What is the percentage of white cast iron & grey cast iron? Also tell the main Difference between them?
What is the percentage of white cast iron & grey cast iron? Also tell the main Difference between them?
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Cast irons are basically iron-carbon alloys having carbon quantity more than 2.11wt% i.e. more than the maximum solid solubility of carbon in austenite. Eutectic reactions take place during solidification. Cast irons are brittle and can not be forged, rolled, drawn etc. Initially there were two typeRead more
Cast irons are basically iron-carbon alloys having carbon quantity more than 2.11wt% i.e. more than the maximum solid solubility of carbon in austenite. Eutectic reactions take place during solidification. Cast irons are brittle and can not be forged, rolled, drawn etc.
Initially there were two types of cast iron. WHITE CAST IRON and GRAY CAST IRON.
See lessCarbon in cast iron may either be in the form of cementite or graphite flakes.
WHITE CAST IRON have all the carbon in the combined cementite form. Cementite is a hard and brittle compound. The fractured surface of the white cast iron looks silvery-white due the presence of cementite and that is why the name white cast iron. WHITE CAST IRON is very brittle and can not be machined as it very hard sue to the presence of the brittle cementite. It finds very little application.
GRAY CAST IRON Gray cast iron has carbon in the free form of graphite. Graphite is soft, brittle and gray and thus imparts gray color to the fractured surface. Cast irons containing graphite (as flakes) are called gray cast irons. The sharp rims that appear in cross section as pointed ends act as stRead more
GRAY CAST IRON
Gray cast iron has carbon in the free form of graphite. Graphite is soft, brittle and gray and thus imparts gray color to the fractured surface. Cast irons containing graphite (as flakes) are called gray cast irons. The sharp rims that appear in cross section as pointed ends act as stress raisers in the structure and are responsible for considerable reduction in strength and toughness of the castings. The flakes are the cause for brittle fracture.
The compressive strength and hardness of the gray cast iron are quiet high and very close to the properties of steel of similar composition and matrix structure. The yield strength, tensile strength, bending, torsional strength and toughness of the gray iron are much less than steel. The microstructure of gray cast iron consists of graphite flakes embedded in the steel matri.
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