Knowledge Bank
Characteristics of Aluminum Alloys
Selection of an aluminum allow for die casting required evaluation not only of physical properties, constants, and chemical composition of the alloy, but also of its inherent characteristics and their effect on production of the die casting and in finishing.
The table includes certain casting and other outstanding characteristics which are usually considered in selecting a die casting alloy for a specific application. The characteristics are rated from (1) to (5), (1) being the best and (5) being the least desirable alloy. In applying these ratings, it should be noted that all the alloys have sufficiently good characteristics to be accepted by users and producers of die castings. Hence a rating of (5) indicates a commercial alloy, although in certain cases its application may be limited or its manufacture may be restricted to relatively simple die castings.
| Die Casting Characteristics | Other Characteristics (k) | |||||||||||
| (a) | (b) | (c) | (d) | (e) | (f) | (g) | (h) | (i) | (j) | |||
| Alloy | Approximate Melting Range *F | |||||||||||
| Standard | ||||||||||||
| 13, A13 | 1065 – 1080 | 1 | 1 | 1 | 1 | 2 | 4 | 5 | 3 | 5 | 3 | 3 |
| 380, A380 | 1000 – 1100 | 2 | 2 | 2 | 1 | 4 | 3 | 3 | 1 | 3 | 4 | 3 |
| Special | ||||||||||||
| 43 | 1065 – 1170 | 3 | 3 | 4 | 4 | 2 | 5 | 4 | 2 | 2 | 2 | 5 |
| 218 | 995 – 1150 | 5 | 5 | 5 | 5 | 1 | 1 | 1 | 5 | 1 | 1 | 4 |
| 360, A360 | 1035 – 1105 | 1 | 2 | 3 | 2 | 2 | 3 | 3 | 2 | 3 | 3 | 1 |
| 383 | 960 – 1080 | 1 | 2 | 1 | 2 | 3 | 2 | 3 | 1 | 3 | 4 | 2 |
| 384 | 960 – 1080 | 2 | 2 | 1 | 2 | 5 | 3 | 5 | 2 | 4 | 5 | 2 |
- Ability of alloy to withstand stresses from contraction while cooling through hot- short or brittle temperature range.
- Ability of molten alloy to flow readily in die and fill thin sections.
- Ability of molten alloy to flow without sticking to the die surfaces. Ratings given for antisoldering are based on nominal iron compositions of approximately 1%.
- Based on resistance of alloy in standard type salt spray test.
- Composite rating based on ease of cutting, chip characteristics, quality of finish, and tool life.
- Composite rating based on ease of polishing and quality of finish provided by typical polishing procedure.
- Ability of the die casting to take and hold an electroplate applied by present standard methods.
- Rated on lightness of color, brightness, and uniformity of clear anodized coating applied in sulphuric acid electrolyte. Generally aluminium die castings are unsuitable for light color anodizing where pleasing apperances is required.
- Rated on combined resistance of coating and base alloy to corrosion.
- Rating based on tensile and yield strengths at temperatures up to 500 F (260), after prolonged heating at testing temperature.
- Die casting are not usually solution heat treated. Low temperature aging treatments may be used for stress relief or dimensional stability.
- Die castings are not generally gas or arc welded or brazed.
Note – These data should be used in connection with ADCI-M2 and M3 in determining selection of an aluminium alloy die casting.