ZAMAK (or Zamac , formerly trademarked as MAZAK) is a family of alloys with a base metal of zinc and alloying elements of aluminium, magnesium, and copper.
Zamak alloys are part of the zinc aluminum alloy family; they are distinguished from the other ZA alloys because of their constant 4% aluminium composition.
The name zamak is an acronym of the German names for the metals of which the alloys are composed: Zink (zinc), Aluminium, Magnesium and Kupfer(copper). The New Jersey Zinc Company developed zamak alloys in 1929.
The most common zamak alloy is zamak 3. Besides that, zamak 2, zamak 5 and zamak 7 are also commercially used.These alloys are most commonly die cast. Zamak alloys (particularly #3 and #5) are frequently used in the spin castingindustry.
A large problem with early zinc die casting materials was zinc pest, owing to impurities in the alloys. Zamak avoided this by the use of 99.99% pure zinc metal, produced by New Jersey Zinc’s use of a refluxer as part of the smelting process.
Zamak can be electroplated, wet painted, and chromate conversion coated well.
Mazak
In the early 1930s Morris Ashby in Britain had licensed the New Jersey zamak alloy. The 99.99%-purity refluxer zinc was not available in Britain and so they acquired the right to manufacture the alloy using a locally available electrolytically refined zinc of 99.95% purity. This was given the name Mazak, partly to distinguish it from zamak and partly from the initials of Morris Ashby. In 1933, National Smelting licensed the refluxer patent with the intent of using it to produce 99.99% zinc in their plant at Avonmouth.
Zamak Standards
Zinc alloy chemical composition standards are defined per country by the standard listed below:
| Zinc alloy standards per country | ||
| Country | Zinc ingot | Zinc casting |
| Europe | EN1774 | EN12844 |
| US | ASTM B240 | ASTM B86 |
| Japan | JIS H2201 | JIS H5301 |
| Australia | AS 1881 – SAA H63 | AS 1881 – SAA H64 |
| China | GB 8738-88 | – |
| Canada | CSA HZ3 | CSA HZ11 |
| International | ISO 301 | – |
Zamak goes by many different names based on standard and/or country:
| Various names for zamak alloys | ||||||||||||
| Traditional name | Short composition name | Form | Common | ASTM† | Short European designation | JIS | China | UK BS 1004 | France NFA 55-010 | Germany DIN 1743-2 | UNS | Other |
| Zamak 2 or Kirksite | ZnAl4Cu3 | Ingot | Alloy 2 | AC 43A | ZL0430 | – | ZX04 | – | Z-A4U3 | Z430 | Z35540 | ZL2, ZA-2, ZN-002 |
| Cast | ZP0430 | – | Z35541 | ZP2, ZA-2, ZN-002 | ||||||||
| Zamak 3 | ZnAl4 | Ingot | Alloy 3 | AG 40A | ZL0400 | Ingot type 2 | ZX01 | Alloy A | Z-A4 | Z400 | Z35521 | ZL3, ZA-3, ZN-003 |
| Cast | ZP0400 | ZDC2 | – | Z33520 | ZP3, ZA-3, ZN-003 | |||||||
| Zamak 4 | Ingot | Used in Asia only | ZA-4, ZN-004 | |||||||||
| Zamak 5 | ZnAl4Cu1 | Ingot | Alloy 5 | AC 41A | ZL0410 | Ingot type 1 | ZX03 | Alloy B | Z-A4UI | Z410 | Z35530 | ZL5, ZA-5, ZN-005 |
| Cast | ZP0410 | ZDC1 | – | Z35531 | ZP5, ZA-5, ZN-005 | |||||||
| Zamak 7 | ZnAl4Ni | Ingot | Alloy 7 | AG 40B | – | – | ZX02 | – | – | – | Z33522 | ZA-7, ZN-007 |
| Cast | – | Z33523 | ||||||||||
| †color of the cell is the color of the material designated by ASTM B908. | ||||||||||||
The Short European Designation code breaks down as follows (using ZL0430 as the example):
- Z is the material (Z=Zinc)
- P is the use (P=Pressure die casting (casting), L=Ingot)
- 04 is the percent aluminum (04= 4% aluminum)
- 3 is the percent copper (3= 3% copper)
Zamak 2
Zamak 2 has the same composition as zamak 3 with the addition of 3% copper in order to increase strength by 20%, which also increases the price. Zamak 2 has the greatest strength out of all the zamak alloys. Over time it retains its strength and hardness better than the other alloys; however, it becomes more brittle, shrinks, and is less elastic.
Zamak 2 is also known as Kirksite when gravity cast for use as a die. It was originally designed for low volume sheet metal dies. It later gained popularity for making short run injection molding dies. It is also less commonly used for non-sparking tools and mandrels for metal spinning.
Zamak 2 composition per standard | ||||||||||||
| Alloying elements | Impurities | |||||||||||
| Standard | Limit | Al | Cu | Mg | Pb | Cd | Sn | Fe | Ni | Si | In | Tl |
| ASTM B240 (Ingot) | min | 3.9 | 2.6 | 0.025 | – | – | – | – | – | – | – | – |
| max | 4.3 | 2.9 | 0.05 | 0.004 | 0.003 | 0.002 | 0.075 | – | – | – | – | |
| ASTM B86 (Cast) | min | 3.5 | 2.6 | 0.025 | – | – | – | – | – | – | – | – |
| max | 4.3 | 2.9 | 0.05 | 0.005 | 0.004 | 0.003 | 0.1 | – | – | – | – | |
| EN1774 (Ingot) | min | 3.8 | 2.7 | 0.035 | – | – | – | – | – | – | – | – |
| max | 4.2 | 3.3 | 0.06 | 0.003 | 0.003 | 0.001 | 0.02 | 0.001 | 0.02 | – | – | |
| EN12844 (Cast) | min | 3.7 | 2.7 | 0.025 | – | – | – | – | – | – | – | – |
| max | 4.3 | 3.3 | 0.06 | 0.005 | 0.005 | 0.002 | 0.05 | 0.02 | 0.03 | – | – | |
| GB8738-88 | min | 3.9 | 2.6 | 0.03 | – | – | – | – | – | – | – | – |
| max | 4.3 | 3.1 | 0.06 | 0.004 | 0.003 | 0.0015 | 0.035 | – | – | – | – | |
| Zamak 2 properties | ||
| Property | Metric value | Imperial value |
| Mechanical properties | ||
| Ultimate tensile strength | 397 MPa (331 MPa aged) | 58,000 psi |
| Yield strength (0.2% offset) | 361 MPa | 52,000 psi |
| Impact strength | 38 J (7 J aged) | 28 ft-lbf (5 ft-lbf aged) |
| Elongation at Fmax | 3% (2% aged) | |
| Elongation at fracture | 6% | |
| Shear strength | 317 MPa | 46,000 psi |
| Compressive yield strength | 641 MPa | 93,000 psi |
| Fatigue strength (reverse bending 5×108 cycles) | 59 MPa | 8,600 psi |
| Hardness | 130 Brinell (98 Brinell aged) | |
| Modulus of elasticity | 96 GPa | 14,000,000 psi |
| Physical properties | ||
| Solidification range (melting range) | 379—390 °C | 714—734 °F |
| Density | 6.8 kg/dm3 | 0.25 lb/in3 |
| Coefficient of thermal expansion | 27.8 μm/m-°C | 15.4 μin/in-°F |
| Thermal conductivity | 105 W/m-K | 729 BTU-in/hr-ft2-°F |
| Electrical resistivity | 6.85 μΩ-cm at 20 °C | 2.70 μΩ-in at 68 °F |
| Latent heat (heat of fusion) | 110 J/g | 4.7×10−5 BTU/lb |
| Specific heat capacity | 419 J/kg-°C | 0.100 BTU/lb-°F |
| Coefficient of friction | 0.08 | |
KS
The KS alloy was developed for spin casting decorative parts. It has the same composition as zamak 2, except with more magnesium in order to produce finer grains and reduce the orange peel effect.
| KS composition | ||||||||||||
| Alloying elements | Impurities | |||||||||||
| Standard | Limit | Al | Cu | Mg | Pb | Cd | Sn | Fe | Ni | Si | In | Tl |
| Nyrstar | min | 3.8 | 2.5 | 0.4 | – | – | – | – | – | – | – | – |
| max | 4.2 | 3.5 | 0.6 | 0.003 | 0.003 | 0.001 | 0.020 | – | – | – | – | |
| KS properties | ||
| Property | Metric value | Imperial value |
| Mechanical properties | ||
| Ultimate tensile strength | < 200 MPa | < 29,000 psi |
| Yield strength (0.2% offset) | < 200 MPa | < 29,000 psi |
| Elongation | < 2% | |
| Hardness | 150 Brinell max | |
| Physical properties | ||
| Solidification range (melting range) | 380—390 °C | 716—734 °F |
| Density | 6.6 g/cm3 | 0.25 lb/in3 |
| Coefficient of thermal expansion | 28.0 μm/m-°C | 15.4 μin/in-°F |
| Thermal conductivity | 105 W/m-K | 729 BTU-in/hr-ft2-°F |
| Electrical conductivity | 25% IACS | |
| Specific heat capacity | 419 J/kg-°C | 0.100 BTU/lb-°F |
| Coefficient of friction | 0.08 | |
Zamak 3
Zamak 3 is the de facto standard for the zamak series of zinc alloys; all other zinc alloys are compared to this. Zamak 3 has the base composition for the zamak alloys (96% zinc, 4% aluminum). It has excellent castability and long term dimensional stability. More than 70% of all North American zinc die castings are made from zamak 3.
| Zamak 3 composition per standard | ||||||||||||
| Alloying elements | Impurities | |||||||||||
| Standard | Limit | Al | Cu† | Mg | Pb | Cd | Sn | Fe | Ni | Si | In | Tl |
| ASTM B240 (Ingot) | min | 3.9 | – | 0.025 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.1 | 0.05 | 0.004 | 0.003 | 0.002 | 0.035 | – | – | – | – | |
| ASTM B86 (Cast) | min | 3.5 | – | 0.025 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.25 | 0.05 | 0.005 | 0.004 | 0.003 | 0.1 | – | – | – | – | |
| EN1774 (Ingot) | min | 3.8 | – | 0.035 | – | – | – | – | – | – | – | – |
| max | 4.2 | 0.03 | 0.06 | 0.003 | 0.003 | 0.001 | 0.02 | 0.001 | 0.02 | – | – | |
| EN12844 (Cast) | min | 3.7 | – | 0.025 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.1 | 0.06 | 0.005 | 0.005 | 0.002 | 0.05 | 0.02 | 0.03 | – | – | |
| JIS H2201 (Ingot) | min | 3.9 | – | 0.03 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.03 | 0.06 | 0.003 | 0.002 | 0.001 | 0.075 | – | – | – | – | |
| JIS H5301 (Cast) | min | 3.5 | – | 0.02 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.25 | 0.06 | 0.005 | 0.004 | 0.003 | 0.01 | – | – | – | – | |
| AS1881 | min | 3.9 | – | 0.04 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.03 | 0.06 | 0.003 | 0.003 | 0.001 | 0.05 | – | 0.001 | 0.0005 | 0.001 | |
| GB8738-88 | min | 3.9 | – | 0.03 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.1 | 0.06 | 0.004 | 0.003 | 0.0015 | 0.035 | – | – | – | – | |
| †Impurity | ||||||||||||
| Zamak 3 properties | ||
| Property | Metric value | Imperial value |
| Mechanical properties | ||
| Ultimate tensile strength | 268 MPa | 38,900 psi |
| Yield strength (0.2% offset) | 208 MPa | 30,200 psi |
| Impact strength | 46 J (56 J aged) | 34 ft-lbf (41 ft-lbf aged) |
| Elongation at Fmax | 3% | |
| Elongation at fracture | 6.3% (16% aged) | |
| Shear strength | 214 MPa | 31,000 psi |
| Compressive yield strength | 414 MPa | 60,000 psi |
| Fatigue strength (reverse bending 5×108 cycles) | 48 MPa | 7,000 psi |
| Hardness | 97 Brinell | |
| Modulus of elasticity | 96 GPa | 14,000,000 psi |
| Physical properties | ||
| Solidification range (melting range) | 381—387 °C | 718—729 °F |
| Density | 6.7 g/cm3 | 0.24 lb/in3 |
| Coefficient of thermal expansion | 27.4 μm/m-°C | 15.2 μin/in-°F |
| Thermal conductivity | 113 W/mK | 784 BTU-in/hr-ft2-°F |
| Electrical resistivity | 6.37 μΩ-cm at 20 °C | 2.51 μΩ-in at 68 °F |
| Latent heat (heat of fusion) | 110 J/g | 4.7×10−5 BTU/lb |
| Specific heat capacity | 419 J/kg-°C | 0.100 BTU/lb-°F |
| Coefficient of friction | 0.07 | |
Zamak 4
Zamak 4 was developed for the Asian markets to reduce the effects of die soldering while maintaining the ductility of zamak 3. This was achieved by using half the amount of copper from the zamak 5 composition.
| Zamak 4 composition per standard | ||||||||||||
| Alloying elements | Impurities | |||||||||||
| Standard | Limit | Al | Cu | Mg | Pb | Cd | Sn | Fe | Ni | Si | In | Tl |
| Ningbo Jinyi Alloy Material Co. | min | 3.9 | 0.3 | 0.03 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.5 | 0.06 | 0.003 | 0.002 | 0.002 | 0.075 | – | – | – | – | |
| Genesis Alloys Ltd. | min | 3.9 | 0.3 | 0.04 | – | – | – | – | – | – | – | – |
| max | 4.2 | 0.4 | 0.05 | 0.003 | 0.002 | 0.001 | 0.02 | 0.001 | 0.02 | 0.0005 | 0.001 | |
| Zamak 4 properties | ||
| Property | Metric value | Imperial value |
| Mechanical properties | ||
| Ultimate tensile strength | 317 MPa | 46,000 psi |
| Yield strength (0.2% offset) | 221—269 MPa | 32,000—39,000 psi |
| Impact strength | 61 J (7 J aged) | 45 ft-lbf (5 ft-lbf aged) |
| Elongation | 7% | |
| Shear strength | 214—262 MPa | 31,000—38,000 psi |
| Compressive yield strength | 414—600 MPa | 60,000—87,000 psi |
| Fatigue strength (rotary bending 5×108cycles) | 48—57 MPa | 7,000—8,300 psi |
| Hardness | 91 Brinell | |
| Physical properties | ||
| Solidification range (melting range) | 380—386 °C | 716—727 °F |
| Density | 6.6 g/cm3 | 0.24 lb/in3 |
| Coefficient of thermal expansion | 27.4 μm/m-°C | 15.2 μin/in-°F |
| Thermal conductivity | 108.9—113.0 W/m-K @ 100 °C | 755.6—784.0 BTU-in/hr-ft2-°F @ 212 °F |
| Electrical conductivity | 26-27% IACS | |
| Specific heat capacity | 418.7 J/kg-°C | 0.100 BTU/lb-°F |
Zamak 5
Zamak 5 has the same composition as zamak 3 with the addition of 1% copper in order to increase strength (by approximately 10%), hardness and corrosive resistance, but reduces ductility.It also has less dimensional accuracy. Zamak 5 is more commonly used in Europe.
| Zamak 5 composition per standard | |||||||||||||
| Alloying elements | Impurities | ||||||||||||
| Standard | Limit | Al | Cu | Mg | Pb | Cd | Sn | Fe | Ni | Si | In | Tl | Zn |
| ASTM B240 (Ingot) | min | 3.9 | 0.75 | 0.03 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.25 | 0.06 | 0.004 | 0.003 | 0.002 | 0.075 | – | – | – | – | ||
| ASTM B86 (Cast) | min | 3.5 | 0.75 | 0.03 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.25 | 0.06 | 0.005 | 0.004 | 0.003 | 0.1 | – | – | – | – | ||
| EN1774 (Ingot) | min | 3.8 | 0.7 | 0.035 | – | – | – | – | – | – | – | – | |
| max | 4.2 | 1.1 | 0.06 | 0.003 | 0.003 | 0.001 | 0.02 | 0.001 | 0.02 | – | – | ||
| EN12844 (Cast) | min | 3.7 | 0.7 | 0.025 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.2 | 0.06 | 0.005 | 0.005 | 0.002 | 0.05 | 0.02 | 0.03 | – | – | ||
| JIS H2201 (Ingot) | min | 3.9 | 0.75 | 0.03 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.25 | 0.06 | 0.003 | 0.002 | 0.001 | 0.075 | – | – | – | – | ||
| JIS H5301 (Cast) | min | 3.5 | 0.75 | 0.02 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.25 | 0.06 | 0.005 | 0.004 | 0.003 | 0.01 | – | – | – | – | ||
| AS1881 | min | 3.9 | 0.75 | 0.04 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.25 | 0.06 | 0.003 | 0.003 | 0.001 | 0.05 | – | 0.001 | 0.0005 | 0.001 | ||
| GB8738-88 | min | 3.9 | 0.7 | 0.03 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.1 | 0.06 | 0.004 | 0.003 | 0.0015 | 0.035 | – | – | – | – | ||
| Zamak 5 properties | ||
| Property | Metric value | Imperial value |
| Mechanical properties | ||
| Ultimate tensile strength | 331 MPa (270 MPa aged) | 48,000 psi (39,000 psi aged) |
| Yield strength (0.2% offset) | 295 MPa | 43,000 psi |
| Impact strength | 52 J (56 J aged) | 38 ft-lbf (41 ft-lbf aged) |
| Elongation at Fmax | 2% | |
| Elongation at fracture | 3.6% (13% aged) | |
| Shear strength | 262 MPa | 38,000 psi |
| Compressive yield strength | 600 MPa | 87,000 psi |
| Fatigue strength (reverse bending 5×108 cycles) | 57 MPa | 8,300 psi |
| Hardness | 91 Brinell | |
| Modulus of elasticity | 96 GPa | 14,000,000 psi |
| Physical properties | ||
| Solidification range (melting range) | 380—386 °C | 716—727 °F |
| Density | 6.7 kg/dm3 | 0.24 lb/in3 |
| Coefficient of thermal expansion | 27.4 μm/m-°C | 15.2 μin/in-°F |
| Thermal conductivity | 109 W/mK | 756 BTU-in/hr-ft2-°F |
| Electrical resistivity | 6.54 μΩ-cm at 20 °C | 2.57 μΩ-in at 68 °F |
| Latent heat (heat of fusion) | 110 J/g | 4.7×10−5 BTU/lb |
| Specific heat capacity | 419 J/kg-°C | 0.100 BTU/lb-°F |
| Coefficient of friction | 0.08 | |
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.
| Zamak 7 composition per standard | ||||||||||||
| 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 | ||||||||||||
| Zamak 7 properties | ||
| Property | Metric value | Imperial 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 5×108 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 |