Tuesday, May 3, 2011

The Basic Cast Iron Fabrication Process

Cast iron products are part of most Americans' daily routine.

Cast iron is fabricated into a wide array of products and differs from wrought iron because it is not malleable. Since it cannot be worked into various shapes, by hand or machine, it must be molten and cast into the finished product being fabricated. Cast iron's carbon content prevents malleability, but it also allows a comparatively low melting point when compared to purer metals. Cast iron's durability is one reason it is used in the production of heavy-duty machinery.


The cast iron fabrication process begins with the smelting process. Iron ore, limestone and carbon are placed inside a blast furnace and a blast of extremely hot air passes through the raw ingredients. This not only infuses oxygen into the mix, but melts the iron, limestone and carbon. Blast furnaces are capable of reaching temperatures in the thousands of degrees; cast iron turns to liquid form between 2,150 and 2,360 degrees. When the mixture melts, it is drained out of the furnace and into molds. Once the cast iron cools, it is called "pig iron."


Pig iron is sold to a variety of manufacturers, who then fabricate the iron into finished products, such as engine blocks, iron beams for construction and everyday items such as golf clubs and cast-iron cookware. The cast iron is eventually re-molten in a furnace and poured into molds during the fabrication process.

Making Molds

Most molds for a specific company's product are initially designed on a computer, then fabricated into a wax master. In the golf club mold manufacturing process, the wax master club's surface is slightly melted, then dipped into quicksand. When the quicksand adheres to the wax club, it is refrigerated. The process is repeated up to five times, creating a finished mold used in the iron casting process. Quicksand can handle molten iron's high temperatures during the fabrication process.


Once the mold is ready, it is heated to the same temperature as the molten iron. The iron is then poured into the mold and placed on a bed of sand to cool. Once the cast iron is cool, the quicksand mold is then broken away, exposing the product. Depending on the particular cast iron product being fabricated, it is then finished as required.

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