Zamak

Zamak (formerly trademarked as ZAMAK[1] and also known as Zamac) is a family of alloys with a base metal of zinc and alloying elements of aluminium, magnesium, and copper.

Zamak ingot

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.[2]

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).[2] The New Jersey Zinc Company developed zamak alloys in 1929. Zinc alloys are popularly referred to as pot metal or white metal. While zamak is held to higher industrial standards, it is still considered a pot metal.

The most common zamak alloy is zamak 3. Besides that, zamak 2, zamak 5 and zamak 7 are also commercially used.[2] These alloys are most commonly die cast.[2] Zamak alloys (particularly #3 and #5) are frequently used in the spin casting industry.

A large problem with early zinc die casting materials was zinc pest, owing to impurities in the alloys.[3] 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.[4]

ZAMAK

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.[5]

Standards

Zinc alloy chemical composition standards are defined per country by the standard listed below:

Zinc alloy standards per country[6]
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[7] France NFA 55-010[7] Germany DIN 1743-2[7] UNS Other
Zamak 2[8][9]
or
Kirksite[10]		 ZnAl4Cu3[11] Ingot Alloy 2[8][9] AC 43A[8][9] ZL0430[11] - ZX04[12] - Z-A4U3[11] Z430[11] Z35540[9] ZL2, ZA-2, ZN-002[13]
Cast ZP0430 - Z35541[8] ZP2, ZA-2, ZN-002[13]
Zamak 3[8][9] ZnAl4[11] Ingot Alloy 3[8][9] AG 40A[8][9] ZL0400[11] Ingot type 2[14] ZX01[12] Alloy A[11] Z-A4[11] Z400[11] Z35521[9] ZL3, ZA-3, ZN-003[13]
Cast ZP0400 ZDC2[15] - Z33520[8] ZP3, ZA-3, ZN-003[13]
Zamak 4[16] Ingot Used in Asia only ZA-4, ZN-004[13]
Zamak 5[8][9] ZnAl4Cu1[11] Ingot Alloy 5[8][9] AC 41A[8][9] ZL0410[11] Ingot type 1[14] ZX03[12] Alloy B[11] Z-A4UI[11] Z410[11] Z35530[9] ZL5, ZA-5, ZN-005[13]
Cast ZP0410 ZDC1[15] - Z35531[8] ZP5, ZA-5, ZN-005[13]
Zamak 7[8][9] ZnAl4Ni[12] Ingot Alloy 7[8][9] AG 40B[8][9] - - ZX02[12] - - - Z33522[9] ZA-7, ZN-007[13]
Cast - Z33523[8]
†color of the cell is the color of the material designated by ASTM B908.[2]

The Short European Designation code breaks down as follows (using ZL0430 as the example):[11]

  • 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.[17]

Zamak 2 is also known as Kirksite when gravity cast for use as a die.[2][18] It was originally designed for low volume sheet metal dies.[19][20] It later gained popularity for making short run injection molding dies.[19] 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[21] (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[22] (Cast) min 3.5 2.6 0.025 - - - - - - - -
max 4.3 2.9 0.05 0.005 0.004 0.003 0.1 - - - -
EN1774[23] (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[24] (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[12] 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[17]
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 5x108 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 4.7x10−5 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.[25]

KS composition[25]
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[25]
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.[2]

Zamak 3 composition per standard
Alloying elements Impurities
Standard Limit Al Cu† Mg Pb Cd Sn Fe Ni Si In Tl
ASTM B240[21] (Ingot) min 3.9 - 0.025 - - - - - - - -
max 4.3 0.1 0.05 0.004 0.003 0.002 0.035 - - - -
ASTM B86[22] (Cast) min 3.5 - 0.025 - - - - - - - -
max 4.3 0.25 0.05 0.005 0.004 0.003 0.1 - - - -
EN1774[23] (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[24] (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[14] (Ingot) min 3.9 - 0.03 - - - - - - - -
max 4.3 0.03 0.06 0.003 0.002 0.001 0.075 - - - -
JIS H5301[15] (Cast) min 3.5 - 0.02 - - - - - - - -
max 4.3 0.25 0.06 0.005 0.004 0.003 0.01 - - - -
AS1881[26] 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[12] min 3.9 - 0.03 - - - - - - - -
max 4.3 0.1 0.06 0.004 0.003 0.0015 0.035 - - - -
†Impurity
Zamak 3 properties[4]
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 5x108 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 4.7x10−5 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.[27]

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.[13] 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.[28] 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[29]
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 5x108 cycles) 48—57 MPa 7,000—8,300 psi
Hardness 91 Brinell
Physical properties[30]
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%[17]), hardness and corrosive resistance, but reduces ductility.[31] It also has less dimensional accuracy.[31] Zamak 5 is more commonly used in Europe.[2]

Zamak 5 composition per standard
Alloying elements Impurities
Standard Limit Al Cu Mg Pb Cd Sn Fe Ni Si In Tl Zn
ASTM B240[21] (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[22] (Cast) min 3.5 0.75 0.03 - - - - - - - -
max 4.3 1.25 0.06 0.005 0.004 0.003 0.1 - - - -
EN1774[23] (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[24] (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[14] (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[15] (Cast) min 3.5 0.75 0.02 - - - - - - - -
max 4.3 1.25 0.06 0.005 0.004 0.003 0.01 - - - -
AS1881[26] 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[12] 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[31]
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 5x108 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 4.7x10−5 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.[2]

Zamak 7 composition per standard
Alloying elements Impurities
Standard Limit Al Cu† Mg Pb Cd Sn Fe Ni‡ Si In Tl
ASTM B240[21] (Ingot) min 3.9 - 0.01 - - - - - - - -
max 4.3 0.1 0.02 0.002 0.002 0.001 0.075 - - - -
ASTM B86[22] (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[12] 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[32]
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 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

Uses

Common uses for zamak alloys include:[33]

Zamak alloys are also used in firearms, including those manufactured by:

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See also

References
  1. Zamak Latest Status Info, retrieved 2008-03-02
  2. Diecasting Alloys, retrieved 2008-03-02
  3. Wanhill, R.J.H.; Hattenberg, T. (May 2005), Corrosion-induced cracking of model train zinc-aluminum die castings (PDF), National Aerospace Laboratory NLR, NLR-TP-2005-205, archived from the original (PDF) on 2011-07-16.
  4. ZL3/ZL0400/ZnAl4 (Zamak 3), retrieved 2008-02-29
  5. Cocks, E.J.; Walters, B. (1968), A History of the Zinc Smelting Industry in Britain, Harrap, ISBN 0-245-59377-2.
  6. World wide zinc die casting standards, Nyrstar, retrieved 2008-02-25.
  7. Now defunct due to standardization of European countries under EN 1774 & EN 12844.
  8. ASTM B86-04e2 (PDF), 2004-10-01, retrieved 2008-02-10
  9. ASTM B240-98 (PDF), 1998-05-01, retrieved 2008-02-10
  10. Semiatin, S. L. (2006). ASM Handbook, Volume 14B: Metalworking: Sheet Forming. ASM International. ISBN 978-0-87170-710-9.
  11. Alloy designation - cross reference table (PDF), archived from the original (PDF) on 2010-10-31, retrieved 2010-10-31
  12. GB8738 - Chinese standard: zinc alloys ingots for casting (2006), retrieved 2008-02-27
  13. ZN-004, retrieved 2008-03-01
  14. JIS H2201 - Japanese Industrial Standard - Zinc alloy ingot for die casting (1999), retrieved 2008-02-26
  15. JIS H5301 - Japanese Industrial Standard - Zinc alloy die casting (1979), retrieved 2008-02-26
  16. zamak 4 (Alloy 4), retrieved 2008-03-01
  17. ZL2/ZL0430/ZnAl4Cu3 (Zamak 2), retrieved 2008-02-29
  18. Husite Engineering - Benefits of Cast Kirksite Tooling, retrieved April 19, 2011
  19. Armstrong, Paul J.; Petch, Bill, Cast Kirksite Re-Emerges as RT Approach for Molding Plastics, retrieved 2008-03-15.
  20. Parker, Dana T. Building Victory: Aircraft Manufacturing in the Los Angeles Area in World War II, p. 86, 119, 120, Cypress, CA, 2013. ISBN 978-0-9897906-0-4.
  21. ASTM B240: Standard specification for zinc in ingot form for die casting: chemical composition, retrieved 2008-02-27
  22. ASTM B86: Standard specification for zinc die casting: chemical composition, retrieved 2008-02-27
  23. EN1774 Standard - zinc and zinc alloys - alloys for foundry purposes - ingot and liquid, retrieved 2008-02-27
  24. EN12844: Standard - zinc and zinc alloys - castings - specification (September 1998), retrieved 2008-02-27
  25. KS (spin casting alloy), retrieved 2008-03-15
  26. AS1881 - Australia standard - Zinc alloys - casting ingots and casting requirements (1986), retrieved 2008-02-27
  27. zamak 4 (Alloy 4), retrieved 2008-03-09
  28. Genesis Alloy 4, retrieved 2008-03-01
  29. Zinc alloy mechanical characteristics, retrieved 2008-03-01
  30. Zinc alloy physical characteristics, retrieved 2008-03-01
  31. Zinc Die Casting Alloy Guide (PDF), retrieved 2008-02-29
  32. Zinc Alloy 7; AG40B; Zn-4Al-0.015Mg, retrieved 2008-02-29
  33. Peñoles zamak, retrieved 2008-03-02
  34. Zinc alloy various purposes, retrieved 2008-03-02
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