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Zamak Technical Information

Zamak Technical Information and Alloy Specs

Zamak, also known as Zamac, includes a family of alloys that contain a base metal of zinc and alloying elements of aluminum magnesium and copper. Zamak alloys were initially developed in the 1920’s by the New Jersey Zinc Company. The name Zamak comes from the basic metallurgy of the alloy group: Z – Zinc; A – Aluminum; MA – Magnesium; and K -Kopper (i.e. German). Zamak 3 is the most common alloy for hot chamber die casting. Other Zamak alloys include Zamak 2, Zamak 5 and Zamak 7.

Zamak is quite versatile and can easily be chromate conversion coated, wet painted, electroplated.

Zinc Alloy Standards Per Country

CountryZinc IngotZinc Casting
EuropeEN1774EN12844
United StatesASTM B240ASTM B86
JapanJIS H2201JIS H5301
AustraliaAS 1881 - SAA H63AS 1881 - SAA H64
ChinaGB 8738-88-
CanadaCSA HZ3CSA HZ11
InternationalISO 301-

Zinc Alloys – Chemical Composition Charts

AlloyDescriptionKey Points
Zamak #3Zamak #3 alloy is the most common choice when considering zinc die casting. It sets the standard by which other zinc alloys are rated in terms of die casting. It has excellent balance of desirable physical and mechanical properties, long-term dimensional stability, and superb castability. Zamak 3 main compositions consists of 96% zinc, 4% aluminum. Over 70% of North American Zinc die castings are of Zamak #3. One of the reasons for its popularity is because it offers excellent finishing characteristics for plating, painting, and chromate treatments.Zamak #3 is the most popular choice when considering zinc die castings. It is the standard by which other zinc alloys are rated in terms of die casting. Zamak 3 provides excellent ductility and impact strength. It also works very well with finishing operations and multiple plating.
Zamak #4Zamak #5 alloy castings have the same composition as #3 with the addition of 1% copper which makes them 10% stronger. Although #5 alloy castings are marginally stronger and harder than #3 castings, these improvements are tempered by a reduction in ductility. It also has less dimensional accuracy. Many material specifiers often use Zinc #3 and will often strengthen components by design modifications rather than using Zamak #5. There are times, however, when an extra measure of tensile performance is needed and #5 alloy castings are recommended.While stronger than #3 alloys, Zamak #5 offers reduced ductility which can affect formability during secondary bending, swaging, crimping operations, or riveting. Zamak 5 is typically used in automotive and small engine applications. Zamak 5 is widely used in Europe and exhibits great castability characteristics.
ZA-8ZA 8 alloy contains more aluminum than Zamak alloys. The numerical designation represents the approximate percentage of Aluminum. ZA 8 is a good gravity casting alloy that is rapidly growing for pressure casting. ZA 8 can be die casted in hot chamber which gives it improved strength and hardness over Zamaks, with the exception of the #2 alloy which is almost identical in performance. When there is question about the performance of standard in Zamak #3 & Zamak #5, ZA 8 is often used because of its good high strength and efficient hot chamber castability.ZA 8 is the an ideal choice for hot chamber casting projects and is even stronger than Zamak 3 and Zamak 5. ZA 8 works well with multiple plating and finishing options.
It contains more aluminum than the Zamak alloys.

 

Chemical Properties

Detailed CompositionZamak #3Zamak #5ZA-8
Aluminum
(Al)
3.5-4.33.5-4.38.0-8.8
Magnesium
(Mg)
0.02-0.050.03-0.080.015-0.030
Copper
(Cu)
0.250.75-1.250.8-1.3
Iron (max)
(Fe)
0.100.100.075
Lead (max) (Pb)0.0050.0050.006
Cadmium (max)
(Cd)
0.0040.0040.006
Tin (max)
(Sn)
0.0030.0030.003
Nickel
(Ni)
---
Zinc
(Zn)
BalanceBalanceBalance

* Single value indicates maximum
** All values are percentage by weight

 

Physical Properties

 Zamak Die Casting AlloysZA Die Casting Alloys
Zamak #3Zamak #5ZA-8
Density0.24
(6.6)
0.24
(6.6)
0.227
(6.3)
Melting Range
°F
(°C)
718-728
(381-387
717-727
(380-386)
707-759
(375-404)
Specific Heat
BTU / lb °F
(J/kg °C)
0.10
(419)
0.210
(419)
0.104
(435)
Coefficient of Thermal Expansion
µ in / in°F
µ m / m°K
15.2
(27.4)
15.2
(27.4)
12.9
(23.2)
Thermal Conductivity
BTU / ft hr°F
(W / m °K)
65.3
(113)
62.9
(109)
66.3
(115)
Electrical Conductivity
µ Ω in.
272627.7
Poisson’s Ration0.300.300.30
Zinc Die Cast part from Northwest Die Casting, Tualatin, Oregon

Material Properties

Mechanical PropertiesZamak Die Casting AlloysZA Die Casting Alloys
Zamak #3Zamak #5ZA-8
Ultimate Tensile Strength
As-Cast ksi (MPa)
41
(283)
48
(328)
54
(372)
Yield Strength
As-Cast ksi (MPa)
32
(221)
39
(269)
41-43
(283-296)
Compressive Yield Strength
As-Cast ksi (MPa)
60
(414)
87
(600)
37
252
Elongation
As-Cast % in 2in. (51mm)
1076-10
Hardness
As-Cast BHN
8291100-106
Shear Strength
As-Cast ksi (MPa)
31
(214)
38
(262)
40
(275)
Impact Strength
As-Cast ft-lb
434824-35
Fatigue Strength (f)
As-Cast ksi (MPa)
6.9
(47.6)
8.2
(56.5)
15
103
Young’s Modulus
psi x 10 6 (GPa)
--12.4
85.5

Other Properties

Commercial ANSI/AA Zamak Die Casting AlloysZA Die Casting Alloys
Zamak #3Zamak #5ZA-8
Resistance to Hot Cracking (a)122
Pressure Tightness123
Casting Ease112
Part Complexity112
Dimensional Accuracy222
Dimensional Stability332
Corrosion Resistance245
Resistance to Cold Defects (b)242
Machining Ease & Quality (c)112
Polishing Ease & Quality112
Electroplating Ease & Quality (d)111
Anodizing (Protection)111
Chemical Coating (Protection)112

(a) Ability to resist formation of cold defects; for example, cold shuts, cold cracks, non-fill “woody”areas, swirls, etc.

(b) Ability to withstand stresses from contraction while cooling through the hot-short or brittle temperature range.

(c) Composite rating based on ease of cutting, chip characteristics, quality of finish, and tool life.

(d) Ability of die casting to take and hold an electroplate applied by present standard methods.

1=Most Desirable

2=Least Desirable

 

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