|
|
Properties of Gray
Cast Iron
Gray cast iron can be regarded as
carbon steel as matrix organization with
graphite flakes added.
Gray
cast iron can be divided
into three categories according to the
different matrix organization:
ferritic matrix of gray cast
iron,
pearlitic gray cast iron matrix,
ferrite and pearlite matrix of
gray cast iron.
The
mechanical properties of gray
cast iron are related with the matrix
organization and the morphology of
graphite.
Flake graphite in gray cast iron can
form serious fragmentation, and graphite
could easily lead to stress
concentration at sharp corners, so that
the tensile strength of gray cast iron,
plastic and toughness will be much lower
than
cast
steel, but it has the
same compressive strength with cast
steel. Therefore, the mechanical
properties of
gray cast iron is also taken as
most normal or even the worst
cast iron.
Meanwhile, the matrix organization of
gray cast iron have an impact on its
mechanical properties. The graphite
sheets in ferrite matrix of gray cast
iron are thick, which cause the lowest
strength and hardness, it is seldom
used. The graphite sheets in pearlitic
matrix of gray cast iron are small, so
have higher strength and hardness.
Therefore, this kind of gray cast iron
is mainly used to manufacture the more
important iron castings. The graphite
sheets in ferrite and pearlite matrix of
gray cast iron are thicker than
pearlitic gray cast iron, so its
mechanical properties are worse.
Therefore, the
gray cast iron of pearlite matrix
has wider application.
Although the
gray cast iron has poor
mechanical properties, it has good
casting properties, good vibration
damping, good wear resistance, good
machinability and low notch sensitivity,
and most important, lower production
cost. Therefore, gray cast iron has wide
range of uses in many areas.
For
class 100 and class 150
gray iron, it can be used to
produce protective cover, cover body,
hand wheels, frame, floor,
hammer, handle, frame, box, bed,
bearing, bench,
pulleys,
pump
body, valve,
pipe,
flywheel and so on.
For
class 200
and class 250
gray iron, it can be used to
produce cylinder, gear, base, flywheel,
bed, cylinder block, cylinder liners,
pistons,
gear boxes, brake wheel,
coupling plate, pressure valve and so
on.
For class 300
gray iron, it can be
used to produce heavy-duty machine
tools, presses, bed, frame, high
pressure hydraulic parts, piston rings,
gears, cams, bushings, crankshaft,
cylinder block, cylinder liner and
cylinder head and so on.
For the gray iron
material standards, please check
normal material comparison table for
grey iron between DIN, ISO, ASTM and GB.
Home |
More Articles |
|
