Zamak 7
Zamak 7 has less magnesium than zamak 3 to increase fluidity and ductility, which is especially useful when casting thin wall components. In order to reduce inter-granular corrosion a small amount of nickel is added and impurities are more strictly controlled.
| Alloying elements | Impurities | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Standard | Limit | Al | Cu† | Mg | Pb | Cd | Sn | Fe | Ni‡ | Si | In | Tl |
| ASTM B240 (Ingot) | min | 3.9 | - | 0.01 | - | - | - | - | - | - | - | - |
| max | 4.3 | 0.1 | 0.02 | 0.002 | 0.002 | 0.001 | 0.075 | - | - | - | - | |
| ASTM B86 (Cast) | min | 3.5 | - | 0.005 | - | - | - | - | 0.005 | - | - | - |
| max | 4.3 | 0.25 | 0.02 | 0.003 | 0.002 | 0.001 | 0.075 | 0.02 | - | - | - | |
| GB8738-88 | min | 3.9 | - | 0.01 | - | - | - | - | 0.005 | - | - | - |
| max | 4.3 | 0.1 | 0.02 | 0.002 | 0.002 | 0.001 | 0.075 | 0.02 | - | - | - | |
| †Impurity ‡Alloying element | ||||||||||||
| Property | Metric value | English value |
|---|---|---|
| Mechanical properties | ||
| Ultimate tensile strength | 285 MPa | 41,300 psi |
| Yield strength (0.2% offset) | 285 MPa | 41,300 psi |
| Impact strength | 58.0 J | 42.8 ft-lbf |
| Elongation at fracture | 14% | |
| Shear strength | 214 MPa | 31,000 psi |
| Compressive yield strength | 414 MPa | 60,000 psi |
| Fatigue strength (reverse bending 5x108 cycles) | 47.0 MPa | 6,820 psi |
| Hardness | 80 Brinell | |
| Physical properties | ||
| Solidification range (melting range) | 381—387 °C | 718—729 °F |
| Coefficient of thermal expansion | 27.4 μm/m-°C | 15.2 μin/in-°F |
| Thermal conductivity | 113 W/m-K | 784 BTU-in/hr-ft2-°F |
| Electrical resistivity | 6.4 μΩ-cm | 2.5 μΩ-in |
| Specific heat capacity | 419 J/kg-°C | 0.100 BTU/lb-°F |
| Casting temperature | 395—425 °C | 743—797 °F |
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