Gray cast iron

The basic building block of the industrial world is gray cast iron. It is a material that has revolutionized many industries, from automotive and construction to engineering. Gray cast iron, renowned for its strength, excellent machinability, economy and proven value in countless applications.

ČSN DIN EN 1561 DIN EN 1691 Rm min (MPa) HB max (Tvrdost dle Brinella)
42 2415 EN-GJL – 150 GG 15 150 180
42 2420 EN-GJL – 200 GG 20 200 220
42 2425 EN-GJL – 250 GG 25 250 240
Composition of gray cast iron

Gray cast iron consists primarily of iron, carbon, and silicon, along with traces of other elements such as manganese, sulfur, and phosphorus. The high carbon content, usually between 2 and 4%, is the cause of the characteristic gray color of the material. The presence of silicon, usually 1 to 3%, promotes the formation of graphite flakes in the iron matrix.

How is this cast iron produced?

The production process of gray cast iron involves melting the raw materials in a furnace, followed by the addition of alloying elements if necessary to achieve the desired properties. The molten cast iron is then poured into molds and let to cool and solidify. During solidification, graphite flakes are formed, which give gray cast iron its characteristic appearance and properties.

Properties and advantages of gray cast iron

Strength and durability

Due to its exceptional strength and durability, gray cast iron is ideal for applications that require high structural integrity. Its ability to withstand heavy loads, wear and tear makes it invaluable in the production of components for the engineering and automotive industries.

Good machinability

Gray cast iron is known for its excellent machinability, which means it can be easily shaped and formed into complex geometric shapes. This feature enables cost-effective production of complex parts with precise tolerances, saving time and resources during the manufacturing process.

Thermal conductivity

For applications that require heat transfer, this cast iron is an excellent choice due to its thermal conductivity. It is commonly used in the production of engine blocks, cylinder heads and other heat-intensive components.

Damping ability

The graphite flakes contained in the gray cast iron act as internal shock absorbers that absorb vibrations and reduce the noise level. This unique property makes it the preferred material for manufacturing components in industries such as construction where noise and vibration reduction is key.

Use of gray cast iron

Due to its exceptional properties, gray cast iron is used in a wide range of industries. Some notable applications include:

  • Automotive: engine blocks, cylinder heads, brake rotors and suspension components
  • Machinery and equipment: machine frames, gears, pulleys and hydraulic components
  • Construction: manhole covers, pipelines and bridge components
  • Household and consumer goods: dishes, stoves and various other household items
Gray cast iron in GIFF a.s. foundry

Gray cast iron is an impressive material. Foundry GIFF a.s. casts gray iron in grades ČSN 42 2415 to ČSN 42 2425 equiv. (GG15 to GG25).

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