Northwest Die Casting
 Minority Owned Die Casting Company
9510 SW Tualatin Rd. Tualatin, Oregon 97062
Tel: 503.885.8200 | sales@nwdiecasting.com

       ISO 9001:2008 Compliant | Aluminum Die Casting | Zinc Die Casting
      
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Northwest Die Casting LLC, Die Castings, Tualatin, OR
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Zamak Technical Information

Zamak (also known as Zamac) is a family of alloys with 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 (e.g., German). Zamak 3 is the most common alloy for hot chamber die casting. Other Zamak alloys are Zamak 2, Zamak 5 and Zamak 7.

Zamak can easily be chromate conversion coated, wet painted, electroplated.


Zinc Alloys Standards Per Country

Country               Zinc Ingot                         Zinc Casting

Europe                     EN1774                                EN12844
USA                       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                                        -

Alloy Description
#3 Zamak #3 alloy is the most common choice when considering zinc die casting. It sets the standard in 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 the Zinc #3. A few reasons why it’s the most common of the zinc alloys is because it offers excellent finishing characteristics for plating, painting, and chromate treatments.
#5 Zamak #5 alloy castings have the same composition as #3 with the addition of 1% copper which makes them stronger, by 10% to be exact. Although No.5 alloy castings are marginally stronger and harder than No. 3 these improvements are tempered by the reduction in ductility. It also has less dimensional accuracy. Many material specifiers often use Zinc #3 and will often strengthen components by design modifications instead of using Zamak #5. There are times however that an extra measure of tensile performance is needed and #5 alloy castings are recommended.




ZA-8
 ZA 8 alloy contains more aluminum than the 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 alike in performance. When there is questions over the performance of standard in Alloy #3 & Alloy #5 ZA 8 is often used because of the good high strength and the efficient hot chamber castability.

    
Key Points
Zamak 3: 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 5: Stronger than #3 alloys however Zamak 5 has a 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 die cast in Europe and exhibits great castability characteristics.

ZA-8: ZA 8 is the an ideal choice for hot chamber casting projects its even stronger than Zamak 3 and Zamak 5. Works well with multiple plating and finishing options.
It contains more aluminum than the Zamak alloys.
ZINC ALLOYS
Chemical Composition Charts
Commercial ANSI/AA Zamak Die Casting Alloys ZA Die Casting Alloys
No.3
No.5
ZA-8

Detailed Composition
Aluminum (Al) 3.5-4.3 3.5-4.3 8.0-8.8
Magnesium (Mg) 0.02-0.05 0.03-0.08 0.015-0.030
Copper  (Cu) 0.25 0.75-1.25 0.8-1.3
Iron (max) (Fe) 0.10 0.10 0.075
Lead (max) (Pb) 0.005 0.005 0.006
Cadmium (max) (Cd) 0.004 0.004 0.006
Tin(max) (Sn) 0.003 0.003 0.003
Nickel  (Ni) - - -
Zinc  (Zn) Balance Balance Balance

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

Typical Material Properties

Commercial ANSI/AA		 Zamak Die Casting Alloys ZA Die Casting Alloys
No.3
No.5
ZA-8

Mechanical Properties

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)

10 7 6-10
Hardness
As-Cast BHN		 82 91 100-106

Shear Strength 

As-Cast ksi (MPa)

 31(214) 38 (262)
 40 (275)
Impact Strength As-Cast ft-lb 43 48 24-35

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)

Physical Properties

Density

lb / in³

(g/cm³)

 0.24
(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.

 27 26 27.7
Poisson’s Ration 0.30 0.30 0.30



Commercial  ANSI/AA 		Zamak Die Casting Alloys
No.3
No.5
ZA-8
Resistance to Hot Cracking (a) 1 2 2
Pressure Tightness 1 2 3
Casting Ease 1 1 2
Part Complexity 1 1 2
Dimensional Accuracy 2 2 2
Dimensional Stability 3 3 2
Corrosion Resistance 2 4 5
Resistance to Cold Defects (b) 2 2 2
Machining Easy & Quality (c) 1 1 2
Polishing Ease & Quality 1 1 2
Electroplating Ease & Quality (d) 1 1 1
Anodizing (Protection) 1 1 1
Chemical Coating (Protection) 1 1 2

(a) The ability of alloy to resist formation of cold defects; for example, cold shuts, cold cracks, non-fill “woody”areas, swirls, etc.
(b) Ability of alloy 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 the die casting to take and hold an electroplate applied by present standard methods.
 

1= Most Desirable

5 = Least Desirable