Zinc Alloys for Die Casting: ZP3, ZP5, ZP2, ZP8
Zamak alloys ZP3, ZP5, ZP2 and ZP8: composition, properties and applications according to EN 12844
Zamak is a zinc alloy with aluminium, magnesium and copper, used to produce metal components by hot-chamber die casting. It has a density of about 6.6 g/cm³, melts at around 385 °C and reproduces very fine details directly in the casting. The EN 12844 standard defines four alloys: ZP3, ZP5, ZP2 and ZP8.
What zamak is: definition and composition
Zinc die casting alloys, commonly known as zamak, are a family of zinc-based alloys with controlled additions of aluminium, magnesium and copper. The name comes from the German initials of the components: Zink, Aluminium, Magnesium and Kupfer (copper).
These alloys are processed with hot-chamber die casting, thanks to their low melting point (~385 °C versus 660 °C for aluminium). This allows faster production cycles, lower energy consumption and a much longer service life of the moulds than with aluminium.
Micrometal works exclusively with primary zinc alloys certified to EN 12844, with full traceability of the material and consistent mechanical properties from batch to batch.
The four zamak alloys: ZP3, ZP5, ZP2, ZP8
ZP3 (Zamak 3): the all-round alloy
ZP3 is the most widely used zinc alloy in the world, accounting for about 70% of global zinc die casting production. It offers the best balance of mechanical properties, dimensional stability, castability and cost. It contains no copper, which makes it the ideal choice for components that need an excellent surface finish and good corrosion resistance.
Typical applications: components for locks and security, furniture and lighting, electronics and taps and fittings.
ZP5 (Zamak 5): higher mechanical strength
ZP5 contains about 1% more copper than ZP3, which gives it higher hardness and tensile strength. It is the second most widely used zinc die casting alloy. Copper also improves creep resistance, making it suitable for components under sustained loads.
Typical applications: lock bodies, structural components, parts for the automotive and gas valve sectors.
ZP2 (Zamak 2): maximum hardness
ZP2 has the highest mechanical strength in the zamak family, with about 3% copper. It is the hardest alloy of the family (about 100 HB). It is less common but essential for applications that require maximum wear resistance.
Typical applications: gears, bearings, bushings, components subject to friction and wear.
ZP8 (ZnAl8Cu1): the high-aluminium alloy
ZP8 contains a higher share of aluminium (about 8.4%) than the other alloys, and corresponds to the North American ZA-8. It offers the highest tensile strength of the four, good creep resistance and lends itself well to galvanic treatments such as chrome or nickel plating.
Typical applications: decorative components, precision instrumentation, parts with demanding dimensional requirements.
Chemical composition and mechanical properties (EN 12844)
Chemical composition (%)
| Alloy | Al | Cu | Mg | Zn |
|---|---|---|---|---|
| ZP3 | 3.9–4.3 | ≤0.10 | 0.03–0.06 | balance |
| ZP5 | 3.9–4.3 | 0.7–1.1 | 0.03–0.06 | balance |
| ZP2 | 3.9–4.3 | 2.7–3.3 | 0.03–0.06 | balance |
| ZP8 | 8.2–8.8 | 0.9–1.3 | 0.02–0.035 | balance |
Mechanical properties compared
| Property | ZP3 | ZP5 | ZP2 | ZP8 |
|---|---|---|---|---|
| Tensile strength (MPa) | 283 | 328 | 359 | 374 |
| Brinell hardness (HB) | 82 | 91 | 100 | 103 |
| Elongation (%) | 10 | 7 | 3 | 6 |
| Density (g/cm³) | 6.6 | 6.7 | 6.8 | 6.3 |
| Melting point (°C) | 386 | 386 | 386 | 404 |
| Castability | Excellent | Very good | Good | Good |
To find out how much your part weighs in each alloy, use our zamak weight calculator: from CAD volume to weight in grams.
Typical values for die-cast test pieces; actual values depend on part geometry and process conditions.
How to choose the right alloy
The choice depends on several factors that our technical team assesses with the customer during the co-design phase:
Static loads → ZP3. Dynamic loads or wear → ZP5 or ZP2.
Chrome/nickel plating → ZP3 or ZP8. Painting → ZP3 or ZP5.
Standard tolerances (typically ±0.05 mm) → ZP3. Sustained loads → ZP5 or ZP8.
Mass production → ZP3 (best castability and cost). Specialised small series → ZP2 or ZP8.
In most cases ZP3 is the best choice. Our technical team recommends moving to ZP5 or ZP2 only when the mechanical specifications require it, and to ZP8 when strength and creep resistance are critical.
Why Micrometal for zinc alloys
Since 1991 Micrometal has worked exclusively with zinc alloys in hot-chamber die casting. This specialisation means:
11 machines
from 20 to 90 tonnes, 2 production shifts
75,000 kg/month
of zamak processed, ISO 9001 certified since 2002
100% traceability
raw material certified to EN 12844
Every alloy batch arrives with its own analysis certificate. Our machines are set up for each alloy, adjusting parameters such as bath temperature, injection speed and clamping pressure.
FAQ — Frequently asked questions about zinc alloys
What is the main difference between ZP3 and ZP5?
The main difference is the copper content: ZP5 contains about 1% copper, which increases hardness (91 vs 82 HB) and tensile strength (328 vs 283 MPa). ZP3, without copper, offers better castability and long-term dimensional stability.
Are zinc alloys recyclable?
Yes, zinc alloys are 100% recyclable without loss of mechanical properties. Production scrap such as runners is remelted and reused directly in the production process.
Can I replace aluminium with a zinc alloy?
In many cases, yes. Zinc alloys allow tighter tolerances (±0.05 mm vs ±0.1 mm), faster cycles, longer-lasting moulds and lower energy consumption than aluminium. Aluminium remains preferable when weight is the deciding factor. For a specific assessment, our technical team can carry out a feasibility review of your component.
What tolerances can be achieved with zinc alloys?
Hot-chamber die casting achieves dimensional tolerances of ±0.05 mm directly from the die (typical value: it depends on part size and geometry). Tighter tolerances can be reached with CNC finishing operations carried out by our partners.
Which alloy is best for galvanic treatments?
ZP3 is suitable for most standard galvanic treatments and is the most commonly plated alloy; ZP8 is also well suited to chrome and nickel plating. Treatments are carried out by our partners on parts we die-cast, with the appropriate preparation cycle (copper undercoat before nickel).