Grey cast iron
Grey cast iron is a type of cast iron with lamellar graphite. It
is an alloy of iron and carbon. The carbon content in the alloy
is between 3.0 and 3.7 %, while it also includes silicon (from
1.5 to 2.5 %), manganese (from 0.5 to 1.4 %) and sulphur (up to
0.12 %). In iron, carbon is excreted in the form of graphite
lamellas and sheets. The fracture surface of such iron is grey;
this is the source of the name.
The properties of grey cast iron mainly depend upon the size and
form of the excreted graphite sheets. The larger the graphite
sheets, the larger the cracks in the cast iron and the lower the
strength of the cast iron.
The main mechanical properties of grey cast iron are its tensile
strength and hardness. Both are regulated by the EN-1561
standard that classifies individual types of cast iron by
quality. We manufacture grey cast iron in the range from
EN-GJL-150 to EN-GJL-300.
Nodular cast iron
Nodular cast iron is grey cast iron with spherical graphite. It
differs from the grey cast iron with lamellar graphite in its
chemical composition, merely due to the fact that, in addition
to the basic elements, it also contains small quantities of
magnesium (from 0.04 to 0.06 %), cerium and rare earths that
influence the formation of graphite spheres.
The properties of nodular cast iron are not only dependent upon
the size, number and arrangement of graphite balls in the cast
iron, but also upon the basic matrix consisting of ferrite and
perlite. At the same hardness levels, nodular cast iron has much
higher tensile strength than grey cast iron; therefore,
toughness and elongation are great advantages of nodular cast
iron.
As in case of grey cast iron, the tensile strength and strain
define the quality of the cast iron. In accordance with the
EN-1563 standard, We manufacture nodular cast iron of quality
levels EN-GJS-400-15, EN-GJS-500-7, EN-GJS-600-3 and
EN-GJS-700-2, as well as cast irons of other quality levels,
according to agreements with clients.
Other cast irons
For specific circumstances of use, we also offer other kinds of
cast iron that, above all, excel for their toughness and
preservation of properties, also at extremely low temperatures.
In particular, this includes cast irons of EN-1561 and EN-1563
standards or a specific standard of the client.
For the railway industry and the wind power plant and pipe
fitting industry, we offer two kinds of other cast irons: grey
cast iron with EN-GJS 400-18 LT spheroidal graphite that has a
more than 18-percent elongation and adequate toughness at low
temperature (up to -20 °C), as well as grey cast iron with
lamellar graphite alloyed by phosphor that meets the standards
for railway products. At our client’s request, we also
manufacture vermicular and other cast irons.
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