Grey Iron has been the most widely used form of Cast Iron over many decades; however
it still has an important part to play in today’s engineering environment. Grey
or Cast Iron is also known as Flake Graphite Iron. A micro structure of this material
reveals that the graphite is in the form of flakes that run through the ferrite
/ pearlite matrix. This graphite structure offers very little ductility but the
many benefits that this material has to offer are:
Cost
Grey Iron is the cheapest of the Iron range to manufacture.
Fluidity
Although this material has a low melting temperature it retains a high degree of
fluidity in the molten condition. This allows complex Grey Iron casting shapes to
be manufactured with thin wall sections.
Wear Properties
As a result of the material structure Grey Iron has excellent wear characteristics.
Machinability
Grey Iron is a superb material to machine. Although there are many forms of Grey
Iron all will machine very easily. With the addition of various alloys the mechanical
properties can be enhanced but the hardness figure on the highest grade will be
below 275BHN.
Damping Properties
This material is the perfect choice for applications where damping properties is
a priority.
Excellent Bearing Properties
The graphite within the structure of Grey Iron provides excellent lubrication properties.
Compressive Strength
Grey Iron has compressive strength comparable to low and medium alloy Carbon Steel
Resistance to Deformation
Casting applications subject to deformation should be specified as Grey Iron.
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Material Designation
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Previous Standard – BS1452
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Tensile Strength (min) – N/mm2
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0.1% Proof Stress (min)information only %
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Elongation (min) N/mm2
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Compression Strength N/mm2
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Brinell Hardness
information only BHN
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Predominant Strucutre
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EN-GLJ-150
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Grade 150
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150 – 250
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98 – 165
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0.8 – 0.3
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600
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155 – 210
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Ferrite/Pearlite
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EN-GLJ-200
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Grade 200
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200 – 300
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130 – 195
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0.8 – 0.3
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720
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175 – 260
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Pearlite
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EN-GLJ-250
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Grade 250
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250 – 350
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165 – 228
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0.8 – 0.3
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840
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195 – 275
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Pearlite
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EN-GLJ-300
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Grade 300
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300 – 400
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195 – 260
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0.8 – 0.3
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960
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215 – 275
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Pearlite
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EN-GLJ-350
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Grade 350
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350 – 450
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228 – 285
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0.8 – 0.3
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1080
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235 – 275
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Pearlite
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