Manufacturing Of Chilled Cast iron

Quick Cooling is called "Chilling" and the iron so produced is "Chilled Iron" . All castings are chilled at their outer surface by coming in contact with the cool sand in the mold. Since cast Iron has a higher thermal conductivity than sand, the chilled portions of the casting undergo rapid solidification and cooling and, thereby produce a herd surface. But this hardness only penetrates about 1 to 2 mm in depth. Sometimes a casting is chilled intentionally and sometimes becomes chilled accidentally to a small depth. Intentionally chilling is carried out by using cast Iron Instead of sand for those portions of the mold where hard surfaces are required. Where these are touched by the molten metal , its surface is suddenly cooled and converted into the white cast Iron.

Chills are used on those castings where some parts are required to have the hardness of white cast iron, While others are required to have relatively soft and tough core of grey cast Iron.

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