Zamak 3 (Zinc Die Cast) vs Zamak 5
Zamak 3 and Zamak 5 are the two most common zinc die-casting alloys, and they are close cousins. Zamak 3 is the industry standard, prized for castability and long-term dimensional stability. Zamak 5 adds roughly 1% copper, which raises strength, hardness, and creep resistance at the cost of slightly lower ductility and somewhat less long-term dimensional stability. The choice is a fine balance of strength versus stability.
The verdict
Choose Zamak 3 as the default for plated, detailed, dimensionally stable zinc die castings with the best ductility. Choose Zamak 5 when you need higher strength, hardness, and creep resistance, accepting slightly reduced ductility and long-term dimensional stability from its added copper.
Side-by-side data
| Property | Zamak 3 (Zinc Die Cast) | Zamak 5 |
|---|---|---|
| Category | Zinc Alloy | Zinc Alloy |
| Density (g/cm³) | 6.6 | 6.6 |
| Tensile strength (MPa) | 268 | 328 |
| Yield strength (MPa) | 208 | 269 |
| Elongation (%) | 10 | 7 |
| Hardness | 82 HB | 91 HB |
| Max service temp (°C) | 90 | 90 |
| Machinability | ●●●●● | ●●●●● |
| Corrosion resistance | ●●●●● | ●●●●● |
| Relative cost | ●●●●● | ●●●●● |
| Thermal cond. (W/m·K) | 113 | 109 |
| Typically used for | Detailed plated die castings | Higher-strength die castings |
Which should you choose?
Choose Zamak 3 when…
- You want the industry-standard zinc die-cast alloy with the widest support
- Long-term dimensional stability is critical for precision-fit parts
- Better ductility helps: 10% elongation vs Zamak 5's 7%
- Producing detailed, decorative parts intended for plating or finishing
- Excellent castability into thin and intricate sections is needed
- Maximum strength is not required and stability is preferred over hardness
Choose Zamak 5 when…
- Higher strength is needed: 328 MPa tensile vs Zamak 3's 268 MPa
- Greater hardness helps wear or load-bearing surfaces (91 HB vs 82 HB)
- Better creep resistance under sustained load is required (from the ~1% copper)
- Higher yield strength matters: 269 MPa vs 208 MPa
- Some loss of ductility (7% vs 10%) is acceptable for the strength gain
- The part still benefits from zinc die casting's detail and finish quality
Key differences that matter
- Both share identical density (6.6 g/cc), the same 90 C temperature limit, and equal machinability (4.5/5).
- Zamak 5's ~1% copper addition is the key difference, raising strength, hardness, and creep resistance.
- Zamak 5 is stronger: 328 MPa tensile and 269 MPa yield vs Zamak 3's 268 and 208 MPa.
- Zamak 3 is more ductile (10% vs 7% elongation) and offers better long-term dimensional stability.
- Cost is nearly identical (Zamak 5 at 1.9/5 vs Zamak 3 at 1.8/5), so price rarely decides the choice.
- Zamak 3 remains the standard default; Zamak 5 is the upgrade when strength or creep resistance is the gating need.
- Corrosion resistance is the same (3.0/5); both typically receive plating or coating for appearance and protection.
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Open the Material SelectorGet a Quote →Frequently asked questions
What is the main difference between Zamak 3 and Zamak 5?
Zamak 5 contains roughly 1% copper that Zamak 3 lacks. That copper raises strength, hardness, and creep resistance, taking tensile from 268 to 328 MPa. The trade-off is slightly lower ductility (7% vs 10% elongation) and somewhat reduced long-term dimensional stability compared to standard Zamak 3.
Which Zamak alloy is the industry standard?
Zamak 3 is the standard and most widely used zinc die-casting alloy. It offers excellent castability, good ductility, and the best long-term dimensional stability, which makes it the default for detailed and plated parts. Zamak 5 is chosen specifically when its added strength or creep resistance is required.
Is Zamak 5 worth the change for higher strength?
Often yes when load or creep resistance matters. Zamak 5 raises tensile strength about 22% (268 to 328 MPa) and hardness from 82 to 91 HB at nearly identical cost. The penalty is reduced ductility and dimensional stability, so favor Zamak 3 for precision-fit or highly detailed parts.
Do Zamak 3 and Zamak 5 have the same temperature limit?
Yes. Both are limited to about 90 C maximum service temperature, the lowest among the die-cast alloys here. Zinc alloys are not suited to hot environments, so for elevated temperatures consider aluminum die-cast alloys like A380 instead. The Zamak choice is about strength versus stability, not heat.
Property values are typical/nominal figures for early-stage guidance only and vary by temper, grade, supplier and heat treatment. Confirm critical specifications against a certified datasheet or with an mfgiq engineer before production.