Die Casting Properties

Typical Mechanical Properties

Aluminum Brass Magnesium Zinc
Tensile strength, psi x 1000 47 55 34 41
Yield strength, psi x 100 (0.2 pct offset) 23 30 23
Shear strength, psi x 1000 28 37 20 31
Fatigue strength, psi x 1000 20 25 14 7
Elongation, pct in 2 in. 3.50 15 3.0 10
Hardness (Brinell) 80 91 63 82
Specific gravity 2.71 8.30 1.80 6.60
Weight, lb/cu. in. .098 0.305 .066 0.24
Melting point (liquid), oF 1100 1670 1105 728
Thermal conductivity, CGS 0.23 0.21 0.16 0.27
Thermal expansion, in./in./oF x 10-6 12.1 12.0 15.0 15.2
Electrical conductivity, pct of copper standard 27 20 10 27
Modulus of elasticity, psi x 106 10.3 15 6.5
Impact strength (Charpy), ft/lb 3.0 40 2.0 43.0

For more specific information, refer to NADCA Product Standards for Die Casting.

Finishing: Decorative

Aluminum Brass Magnesium Zinc
Chrome plating Fair Excellent Fair Excellent
Black chrome plating Fair Excellent Excellent
Colored plating Fair Excellent
Mechanical-polishing & buffing Excellent Excellent Excellent Excellent
Lacquers, enamels, epoxies & acrylics Excellent Excellent Excellent Excellent
Anodizing Fair

Protective

Aluminum Brass Magnesium Zinc
Anodizing-corrosion & abrasion protection Excellent Good Excellent
Chromate conversion-corrosion Excellent Excellent Excellent
Heavy paint, wrinkle, matte finishes-abrasion, corrosion protection & to hide imperfections Excellent Excellent Excellent Excellent

NOTE: This chart does not intend to compare metals. Its purpose is to show the most satisfactory methods of finishing each specific metal.

Processing and Production

Machine Types: Aluminum Brass Magnesium Zinc
Hot chamber (Plunger) No No Yes Yes
Cold chamber Yes Yes Yes Yes
Production range, shots/hr 40-200 40-200 75-400 200-550
Average tool life, no. of shots x 1000 125 20 200 500

Chemical Composition (%)

Aluminum Brass Magnesium Zinc
Aluminum Remainder 0.25 8.3 to 9.7 3.5 to 4.3
Cadmium .004 (max)
Copper 3.0 to 4.0 57.0 (min) 0.35 (max) 0.25 (max)
Iron 1.3 0.50 0.10 (max)
Lead 1.50 .005 (max)
Magnesium 0.10 Remainder .02 to .05
Manganese 0.50 0.25 0.13 (min)
Nickel 0.50 .03 (max) *
Silicon 7.5 to 9.5 0.25 (max) 0.5 (max) *
Tin 0.35 1.50 .003 (max)
Zinc 3.0 Remainder 0.35 to 1.0 Remainder
Other 0.50 0.50 0.3 (max)

Mechanical properties and chemical composition vary for specific alloys. Refer to NADCA Product Standards for Die Casting for details.

Characteristics of Die Casting Alloys

Aluminum Brass Magnesium Zinc
Dimensional stability Good Excellent Excellent Good
Corrosion resistance Good Excellent Fair Fair
Casting ease Good Fair Good Excellent
Part complexity Good Fair Good Excellent
Dimensional accuracy Good Fair Excellent Excellent
Die cost Medium High Medium Low
Machining cost Low Medium Low Low
Finishing cost Medium Low High Low

Chart does not intend to compare metals. Its purpose is to show the most advantageous characteristics of each specific metal. For more specific information, refer to NADCA Product Standards for Die Casting

Dimensional Weight Limits

Aluminum Brass Magnesium Zinc
Maximum weight, lb. 70 10 44 75
Minimum wall thickness, large castings, in. .080 .090 .100 .035
Minimum wall thickness, small castings, in. .040 .055 .040 .015
Minimum variation per in. of diameter or length from drawing dimensions over one in. .0015 .009 .0015 .001
Cast threads, max. per in. external 24 10 24 32
Cored holes, min. diameter in. .080 0.250 .080 .050

The values shown herein represent normal production practice at the most economic level. Greater accuracy involving extra close work or care in production should be specified only when and where necessary since additional cost may be involved.

For more specific information, refer to NADCA Product Standards for Die Casting.