Malleable Cast Iron Hardness Requirements
1.
Pearlitic malleable
iron castings
(ASTM A220 M-88)
Pearlitic malleable
iron castings
(ASTM A220 M-88)
are commonly used in general engineering with the work temperature
from ordinary
to 400 centigrade.
If the purchase
contract requires hardness test, the acceptable hardness range
should be stated, and the test spot should be clearly shown in the
drawings.
Whenever possible, we
should use Brinell hardness test method specified by ASTM E10, and
we’d better use the 3000kg force / 10mm ball test condition, if the
size or shape is not suitable, we can use the 1500kg force / 10mm
ball. In
particular cases,
Brinell hardness tester is not available, so we can choose the
Rockwell hardness test method instead in accordance with the
provisions of ASTM E18.
The mechanical
properties of pearlitic malleable cast iron of different grades are
as follows:
|
Tensile
test requirements |
Typical
hardness range |
|
Grade
|
Tensile
strength
(MPa) |
Yield
strength
(MPa) |
Elongation
(%) |
Typical
hardness
(HB) |
Typical
indentation diameter
(mm) |
|
280M10
310M8
310M6
340M5
410M4
480M3
550M2
620M1 |
400
450
450
480
550
590
650
720 |
280
310
310
340
410
480
550
620 |
10
8
6
5
4
3
2
1 |
149-197
156-197
156-207
179-229
197-241
217-269
241-285
269-321 |
4.3-4.9
4.3-4.8
4.2-4.8
4.0-4.5
3.9-4.3
3.7-4.1
3.6-3.9
3.4-3.7 |
2.
Ferritic malleable iron
castings
(ASTM A47M-90)
This kind of Ferritic
malleable iron castings
(ASTM A47M-90) are
commonly used
under work conditions from room temperature to 400 centigrade in
general engineering.
The tensile test and
hardness requirements of typical parts are as follows:
|
Tensile
test requirements |
Typical
hardness |
|
Grade |
Minimum
tensile strength
MPa |
Minimum
yield strength
MPa |
Elongation
50 mm gauge minimum,% |
Maximum
hardness
HB |
Indentation
diameter mm |
|
22010 |
340 |
220 |
10 |
156 |
4.8 |
3.
Malleable iron castings
for automobiles
(ASTM A602-87)
They are used for
automotive and the same industrial products with the same grade of
ferrite, pearlite, tempered pearlite and tempered martensite. The
castings should be heat-treated.
Hardness requirements
Castings should
implement the necessary control and inspection procedures to ensure
the compliance with the provisions of the hardness range. Hardness
readings should be in accordance with ASTM E10, read after removing
enough thickness of materials from casting surface, which can ensure
the representation of the hardness value. This should be conducted
after negotiations between both parties to determine the casting
surface or area for hardness inspection.
The mechanical
properties of malleable iron castings are as follows:
|
grade |
Hardness
range |
Heat
treatment |
Tensile
strength
Lb / in 2
(MPa) |
Yield
strength residual deformation0.2% lb / in 2 (MPa) |
Elongation
2 inches or 50 mm% |
Elastic
modulus
One million pounds / inch 2
(MPa) |
|
|
≤156HB
≥4.8BID |
Annealing
|
50000
(345) |
32000
(221) |
10
|
25
(172) |
|
M4504 |
163-217HB
4.7-4.1BID |
Air
quenching or liquid quenching& tempering |
65000
(448) |
45000
(310) |
4 |
26
(179) |
|
M5003 |
187-241
HB
4.4-3.9BID |
Air
quenching or liquid quenching& tempering |
75000
(517) |
50000
(345) |
3 |
26
(179) |
|
M5503 |
187-241HB
4.4-3.9BID |
Liquid
quenching& tempering |
75000
(517) |
55000
(379) |
3 |
26
(179) |
|
M7002 |
229-269HB
4.0-3.7BID |
Liquid
quenching& tempering |
90000
(621) |
70000
(483) |
2 |
26
(179) |
|
M8501 |
269-302HB
3.7-3.5BID |
Liquid
quenching& tempering |
105000
(724) |
85000
(586) |
1 |
26
(179) |
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