Ductile iron



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alloy phases

Austenite (γ-iron; hard)
Bainite
Martensite
Cementite (iron carbide; Fe3C)
Ledeburite (ferrite - cementite eutectic, 4.3% carbon)
Ferrite (α-iron, δ-iron; soft)
Pearlite (88% ferrite, 12% cementite)
Spheroidite

Types of Steel

Plain-carbon steel (up to 2.1% carbon)
Stainless steel (alloy with chromium)
HSLA steel (high strength low alloy)
Tool steel (very hard; heat-treated)

Other Iron-based materials

Cast iron (>2.1% carbon)
Wrought iron (almost no carbon)
Ductile iron

Ductile iron, also called ductile cast iron or nodular cast iron, is a type of ductile, as the name implies.

In 1949, Keith Millis, Lee Aunkst, Albert Gagnebin and Norman Pilling received U.S. Patent 2,485,760  on ductile iron production via magnesium treatment.

Metallurgy

Cast iron is an Yttrium has also been studied as a possible nodulizer.

A recent development in ductile iron metallurgy is austempered ductile iron where the metallurgical structure is manipulated through a sophisticated heat treating process.

Composition

A typical chemical analysis of this material:

Other elements such as chromium.

Applications

Much of the annual production of ductile iron is in the form of ductile cast iron pipe, used for water and sewer lines. Ductile iron pipe is stronger, easier to tap, requires less support and provides greater flow area compared to pipe made from other materials. In difficult terrain it can be a better choice than steel pipe.

Castings made of ductile iron are widely used. Examples include automobile components, industrial machinery, wind turbine electrical energy generation, valves, air conditioning machinery, lawn and garden equipment, and agricultural products.

References

US2,485,760 (PDF version) (1949-10-25) Keith Millis Cast Ferrous Alloy 

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Ductile_iron". A list of authors is available in Wikipedia.