+86-13928348837
China Zinc Alloy CNC Machining Factory | Precision Parts Suppliers for Automotive and Electronics
Zinc alloys typically refer to alloys with zinc as the base, primarily alloyed with elements such as aluminum, copper, and magnesium. Their most prominent feature is excellent castability, making them suitable for manufacturing parts with complex shapes.
Simultaneously, their superior machinability allows subsequent CNC precision machining to easily achieve high dimensional accuracy and excellent surface finish.
Furthermore, zinc alloys offer good wear resistance, damping capacity, and comprehensive electromagnetic shielding (EMI/RFI) capability, making them an engineering material that combines functionality with economy.
⚙
Common Zinc Alloy Grades and Characteristics
1. Zamak 3 (Zinc Alloy No. 3)
✦ Characteristics
The most versatile and commonly used die-casting zinc alloy. It possesses the best fluidity and dimensional stability, along with good mechanical properties and surface treatment performance. Its low copper content means its creep resistance and strength are slightly lower than Zamak 5, but it offers better ductility.
🔩 Typical Applications
Complex thin-walled parts without extremely high strength requirements, such as toy models, zipper pulls, small gears, decorative items, and numerous consumer electronics housings.
Zamak 3 Typical Properties (As Die-Cast)
| Property | Value | Notes |
|---|---|---|
| Tensile Strength (MPa) | 280 – 320 | Good overall strength |
| Yield Strength (MPa) | — | |
| Elongation at Break (%) | 10 – 20 | Exhibits good ductility |
| Hardness (Brinell) | ~ 82 | |
| Density (g/cm³) | 6.6 | Significantly higher than aluminum and plastics |
| Note: Values are typical ranges, specific to casting process and condition. | ||
2. Zamak 5 (Zinc Alloy No. 5)
✦ Characteristics
Based on Zamak 3 with the addition of about 1% copper, thereby increasing tensile strength, hardness, and creep resistance, but slightly reducing impact toughness and ductility. It is the most widely used high-strength die-casting zinc alloy.
🔩 Typical Applications
Functional and structural parts requiring higher strength and wear resistance, such as automotive door locks, fuel system components, tool housings, premium hardware, and business machine parts.
Zamak 5 Typical Properties (As Die-Cast)
| Property | Value | Notes |
|---|---|---|
| Tensile Strength (MPa) | 330 – 380 | Strength higher than Zamak 3 |
| Yield Strength (MPa) | — | |
| Elongation at Break (%) | 7 – 15 | |
| Hardness (Brinell) | ~ 91 | Higher hardness, more wear-resistant |
| Density (g/cm³) | 6.7 | Similar to Zamak 3 |
| Note: Values are typical ranges, specific to casting process and condition. | ||
3. ZA-8 (Zinc-Aluminum Alloy No. 8)
✦ Characteristics
A zinc-aluminum alloy containing about 8.4% aluminum, typically produced by gravity casting. It has the best castability among all ZA series alloys and offers excellent bearing properties and wear resistance. Compared to the Zamak series, it retains better strength and dimensional stability at elevated temperatures.
🔩 Typical Applications
Bearings, bushings, sliders, wear-resistant components, and engineering structural parts that need to operate in moderately elevated temperature environments.
4. Kirksite (Mold Zinc Alloy)
✦ Characteristics
A zinc-based alloy specifically designed for manufacturing prototype molds, low-melting-point injection molds, and fixtures. It has a low melting point, is easy to machine, and can quickly and cost-effectively replicate complex mold cavities for small-batch plastic part trial production or sheet metal forming.
🔩 Typical Applications
Prototype injection molds, blow molds, sheet metal stamping/form dies, checking fixtures, and jigs.
Frequently Asked Questions
What is the difference between Zamak 3 and Zamak 5?
Zamak 3 is the standard die-casting zinc alloy known for its excellent fluidity, dimensional stability, and ductility. Zamak 5 adds approximately 1% copper to the Zamak 3 base, which increases tensile strength, hardness, and creep resistance. However, this comes at the cost of slightly reduced ductility and impact toughness. Choose Zamak 5 when higher mechanical strength is required.
What are zinc alloys primarily used for in manufacturing?
Zinc alloys are widely used for die-casting complex-shaped parts across many industries, including automotive components (door locks, fuel system parts), consumer electronics housings, decorative hardware, toy models, zipper pulls, small gears, and precision tooling molds. Their combination of castability, machinability, and surface finish quality makes them highly versatile.
Can zinc alloys provide electromagnetic shielding?
Yes. Zinc alloys offer comprehensive electromagnetic shielding (EMI/RFI) capability, making them a preferred choice for electronic device housings and enclosures where protection against electromagnetic interference is required. This property, combined with their excellent castability and surface finish, makes them ideal for consumer electronics applications.
What is ZA-8 and when should it be used instead of Zamak alloys?
ZA-8 is a zinc-aluminum alloy containing approximately 8.4% aluminum, typically produced by gravity casting. It should be chosen over Zamak alloys when the application requires superior bearing properties, wear resistance, or operation in moderately elevated temperature environments. ZA-8 retains better strength and dimensional stability at higher temperatures than the Zamak series.
What is Kirksite and how is it different from other zinc alloys?
Kirksite is a specialized zinc-based alloy designed specifically for tooling applications rather than end-use parts. Unlike Zamak or ZA alloys used for structural or functional components, Kirksite is used to manufacture prototype molds, low-cost injection molds, blow molds, and forming dies. Its low melting point and easy machinability allow rapid, cost-effective production of tooling for small-batch trials.
How does the density of zinc alloys compare to aluminum alloys and plastics?
Zinc alloys have a significantly higher density than both aluminum alloys and engineering plastics. For example, Zamak 3 has a density of approximately 6.6 g/cm³ and Zamak 5 is about 6.7 g/cm³, compared to roughly 2.7 g/cm³ for aluminum alloys and 1.0–1.5 g/cm³ for most engineering plastics. This higher density gives zinc alloy parts a premium, solid feel, which is desirable in applications such as hardware, decorative items, and consumer products.
Finishes and Post-Processing Options
The zinc alloy substrate is highly suitable for various surface treatments to enhance decoration, protection, or functionality:
Electroplating: Such as chrome, nickel, gold, or silver plating, providing a highly decorative appearance, excellent wear and corrosion resistance. This is the most common choice.
-
Passivation or Chromate Conversion Coating:
-
Powder Coating:
-
Painting:
-
Physical Vapor Deposition (PVD):
Design and Machining Considerations
-
Process Selection:
-
Design Considerations:
-
Material Selection:
Zamak 3 and 5 are suitable for the vast majority of general-purpose parts requiring good appearance and strength; ZA-8 is better for wear and bearing applications; for making rapid tooling, choose specialized alloys like Kirksite.
Ready to Start Your CNC Project?
Send us your drawings to receive professional manufacturing solutions.