Here’s a professional English comparison of Zamak 3 and Zamak 5 zinc alloys:
Classification & Composition (per ASTM B86)
| Alloy | Type | Composition (wt.%) | Key Characteristics |
|---|---|---|---|
| Zamak 3 | Standard Zinc Alloy | Zn 95.5%, Al 4.0%, Cu 0.1% | Optimal fluidity & surface finish |
| Zamak 5 | High-Strength Zinc Alloy | Zn 94.5%, Al 4.0%, Cu 1.0% | Enhanced mechanical properties |
Mechanical Properties Comparison
| Property | Zamak 3 | Zamak 5 |
|---|---|---|
| Tensile Strength (MPa) | 280-320 | 330-380 |
| Yield Strength (MPa) | 210-240 | 250-290 |
| Elongation (%) | 10-20 | 7-15 |
| Hardness (HB) | 80-90 | 90-100 |
| Impact Strength (J) | 50-60 | 40-50 |
| Fatigue Limit (MPa) | 60-80 | 70-90 |
Physical Properties
| Property | Zamak 3 | Zamak 5 |
|---|---|---|
| Density (g/cm³) | 6.6 | 6.7 |
| Melting Point (°C) | 385-390 | 380-386 |
| Thermal Conductivity (W/m·K) | 110-120 | 105-115 |
| Electrical Conductivity (%IACS) | 27-29 | 25-27 |
Key Performance Advantages
Zamak 3:
- Casting Performance: Best flow characteristics (fills down to 0.5mm wall thickness)
- Surface Finish: Excellent for plating/painting
- Cost: ~15% cheaper than Zamak 5
Zamak 5:
- Mechanical Properties: 20% higher strength, better wear resistance
- Dimensional Stability: 30% less aging deformation
- Machinability: Improved surface finish due to copper content
Processing Characteristics
| Process | Zamak 3 | Zamak 5 |
|---|---|---|
| Die Cast Temp. | 400-420°C | 410-430°C |
| Mold Life | 500k-1M cycles | 400k-800k cycles |
| Machining | Easy (long chips) | Moderate (short chips) |
| Polishing | Achieves Ra 0.4μm | Achieves Ra 0.6μm |
Typical Applications
Zamak 3:
- Plumbing fixtures (faucet handles)
- Toy components
- Electronics housings (routers/switches)
Zamak 5:
- Automotive door locks
- Industrial gears/cams
- Premium zipper heads
Corrosion Resistance
- Salt Spray Test (ASTM B117):
- Zamak 3: White rust after 72 hrs
- Zamak 5: White rust after 96 hrs
- Both require surface treatment (chromate conversion/plating) for practical use
Material Selection Guide
- Thin-wall complex parts → Zamak 3
- Load-bearing components → Zamak 5
- Cost-sensitive projects → Zamak 3
- High wear resistance needed → Zamak 5
Special Considerations
Both alloys exhibit “aging growth” (0.1-0.2% dimensional change after 6 months storage)
Avoid direct contact with copper alloys (galvanic corrosion risk)
Zamak 5 scrap requires separate recycling (copper contamination affects remelt quality)
Note: Zamak 5 can gain 10% additional strength through T5 aging treatment (100°C×6h).
Great, Together
