Aluminum Alloys

Aluminum die casting alloys (Table1) are lightweight, offer good corrosion resistance, ease of casting, good mechanical properties and dimensional stability.

Although a variety of aluminum alloys made from primary or recycled metal can be die cast, most designers select standard alloys listed below:

360 — Selected for best corrosion resistance. Special alloys for special applications are available, but their use usually entails significant cost premiums.

380 — An alloy which provides the best combination of utility and cost.

383 & 384 — These alloys are a modification of 380. Both provide better die filling, but with a moderate sacrifice in mechanical properties, such as toughness.

390 — Selected for special applications where high strength, fluidity and wear-resistance/bearing properties are required.

413 (A13) — Used for maximum pressure tightness and fluidity.

Table 1:

COMPOSITION AND PROPERTIES OF ALUMINUM DIE CASTING ALLOYS

10.3

DESIGNATIONS

AA NUMBER

FORMER NO.

COMPOSITION (in percent max. unless shown as range)

A360.0

A360.0

A380.0

A380.0

E380.0

383.0

B383.0

A413.0

A13

B390.0

390

384.0

384

Silicon

9.0-10.0

7.5-9.5

7.5-9.5

9.5-11.5

9.5-11.5

11.0-13.0

16.0-18.0

10.5-12.0

Iron

1.3

1.3

1.3

1.3

1.3

1.3

1.3

1.3

Copper

0.6

3.0-4.0

3.0-4.0

2.0-3.0

2.0-3.0

1.0

4.0-5.0

3.0-4.5

Manganese

0.35

0.50

0.50

0.50

0.50

0.35

0.50

0.50

Magnesium

0.40-0.6

0.10

0.30

0.10

0.30

0.10

0.45-0.65

0.10

Nickel

0.50

0.50

0.50

0.30

0.30

0.50

0.10

0.50

Zinc

0.50

3.0

3.0

3.0

3.0

0.50

1.5

3.0

Tin

0.15

0.35

0.35

0.15

0.15

0.15

0.20

0.35

Titanium

0.20

Total others

0.25

0.50

0.50

0.50

0.50

0.25

0.20 (0.10 ea.)

0.50

Aluminum

Bal.

Bal.

Bal.

Bal.

Bal.

Bal.

Bal.

Bal.

 

PROPERTIES (see notes)

 

Ultimate tensile strength (ksi)

46

47

47

45

45

42

40.5

48

Tensile yield strength (ksi)

24

23

23

22

22

19

35

24

Elongation (% in 2″ G.L.)

3.5

3.5

3.5

3.5

3.5

3.5

1.0 2.5

Hardness (HB)

75

80

80

80

80

120

85

Shear Strength (ksi)

26

27

27

25

25

29

Charpy impact strength (ft. lb.óunnotched)

4.2

3.5

3.5

2.0

Fatigue strength (ksi) (limit @ 500 million cycles)

18

20

20

19

19

20

20

Density (lb./in.3)

0.95

0.98

0.98

0.97

0.97

0.96

0.99

0.98

Melting range (oF) approx.

1035-1105

1000-1100

1000-1100

960-1080

960-1080

1065-1080

945-1200

960-1080

Specific heat (Btu/lb.oF)

0.23 0.23

0.23

0.23

Coefficient of thermal expansion (in./in./oF)

11.8

11.7

11.7

11.5

11.5

10.3

11.7

11.3

Thermal conductivity (Btu/fthr.oF)

65.3

55.6

55.6

55.6

55.6

67.7

78.6

56

Electrical conductivity (% IACS)

29

31

31

23

23

31

25

23

Modulus of elasticity (106 psi)

10.3

10.3

10.3

10.3

10.3

10.3

11.9

10.3