Compacted graphite iron (CGI), also known as vermicular graphite iron (GJV, VG, JV or GGV from the german: "Gusseisen mit Vermiculargraphit") especially in non-English speaking countries, is a

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...

which is gaining popularity in applications that require either greater strength, or lower weight than

cast iron Cast iron is a class of iron–carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impuriti ...

. R.D. Schelleng obtained a patent for the production of compacted graphite iron in 1965.

Metallurgy

The

graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on large ...

in compacted graphite iron differs in structure from that in

gray iron Gray iron, or grey cast iron, is a type of cast iron that has a graphitic microstructure. It is named after the gray color of the fracture it forms, which is due to the presence of graphite.. It is the most common cast iron and the most widely u ...

because the graphite particles are shorter and thicker.

Applications

The first commercial application for compacted graphite iron was for the brake discs for high-speed rail

train In rail transport, a train (from Old French , from Latin , "to pull, to draw") is a series of connected vehicles that run along a railway track and Passenger train, transport people or Rail freight transport, freight. Trains are typically pul ...

s. More recently compacted graphite iron has been used for

diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...

blocks. It has proven to be useful in the manufacture of V topology

s where the loading on the block is very high between the

cylinder bank The engine configuration describes the fundamental operating principles by which internal combustion engines are categorized. Piston engines are often categorized by their cylinder layout, valves and camshafts. Wankel engines are often categorize ...

s, and for heavy goods vehicles which use diesel engines with high combustion pressures. It is also used for

turbo In an internal combustion engine, a turbocharger (often called a turbo) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake gas, forcing more air into the engine in order to pro ...

housings and

exhaust manifold In automotive engineering, an exhaust manifold collects the exhaust gases from multiple cylinders into one pipe. The word ''manifold'' comes from the Old English word ''manigfeald'' (from the Anglo-Saxon ''manig'' anyand ''feald'' old and refe ...

s, in the latter case to reduce corrosion. It is also used in

NASCAR The National Association for Stock Car Auto Racing, LLC (NASCAR) is an American auto racing sanctioning and operating company that is best known for stock car racing. The privately owned company was founded by Bill France Sr. in 1948, and hi ...

engine blocks.

References

Ferrous alloys {{alloy-stub

Metallurgy

Applications

See also

References