Zinc general properties
Zinc and its alloys represent one of the most versatile options in die casting, combining excellent castability with a high density that gives parts superior strength and durability compared to many engineering plastics. A typical ZP5 (ZP0410) alloy part exhibits a density of 6.7 g/cm³ / 0.242 lb/in³ and offers an optimal balance between mechanical strength and the ability to receive high-quality surface finishes, such as chrome plating or paints, making it an industrial standard for the production of precision components in large volumes.
Chemical composition
Section titled “Chemical composition”The chemical composition of the ZP5 (ZP0410) zinc alloy is carefully controlled to optimize its fluidity during injection and its final properties. Aluminum is the main alloying element, improving strength and hardness, while copper contributes to an additional increase in mechanical properties. The precise content of impurities such as lead, cadmium, and tin is maintained at trace levels to prevent intergranular corrosion.
| Element | Content (%) |
|---|---|
| Zinc (Zn) | Remainder |
| Aluminum (Al) | 3.7 – 4.3 |
| Copper (Cu) | 0.7 – 1.2 |
| Magnesium (Mg) | 0.025 – 0.06 |
| Iron (Fe) | 0.05 max. |
| Silicon (Si) | 0.03 max. |
| Nickel (Ni) | 0.02 max. |
| Lead (Pb) | 0.005 max. |
| Cadmium (Cd) | 0.005 max. |
| Tin (Sn) | 0.002 max. |
Mechanical properties (as-cast)
Section titled “Mechanical properties (as-cast)”The mechanical properties presented below correspond to the ZP5 alloy in the as-cast condition, the most common supply state for parts produced by hot chamber die casting.
| Property | Value |
|---|---|
| Tensile strength (Rm) | 330 MPa / 47.9 ksi |
| Yield strength 0.2 % (Rp0.2) | 250 MPa / 36.3 ksi |
| Elongation at break (A) | 5 % in 50 mm |
| Modulus of elasticity (E) | 85 GPa / 12.3 x 10³ ksi |
| Brinell hardness (HB) | 92 HB |
| Impact energy (KV) at +20 °C | 58 J / 42.8 ft·lbf |
| Poisson’s ratio | 0.29 |
Physical and thermal properties
Section titled “Physical and thermal properties”These properties define the material’s behavior during the casting process and its response to service conditions.
| Property | Value |
|---|---|
| Density | 6.6 – 6.7 g/cm³ / 0.238 – 0.242 lb/in³ |
| Melting temperature range | 379 – 388 °C / 714 – 730 °F |
| Thermal conductivity | ~113 W/m·K / 65 BTU·ft/(h·ft²·°F) |
| Specific heat | ~0.42 J/g·°C / 0.10 BTU/lb·°F |
Applications by industry
Section titled “Applications by industry”Thanks to its exceptional fluidity in the molten state, ZP5 alloy allows the economical production of complex and thin-walled geometries with tight dimensional tolerances, often eliminating machining operations. Its ability to be chrome plated, painted, or lacquered makes it ideal for visible parts requiring high aesthetic value. Applications are segmented as follows:
| Industry | Common applications |
|---|---|
| Automotive and transportation | Latch system components, rearview mirror housings, turn signal parts and interior instrumentation, emblems and moldings. |
| Hardware and construction | Door and window handles, locks, hinges, bathroom and furniture fittings, and decorative fasteners. |
| Electronics and office equipment | Housings for electronic devices, precision frames and chassis, projector components, stapler staples, and office machine parts. |
| Consumer goods | Zippers, buckles, power tool housings, die-cast toys, and fashion decorative elements. |
| Decoration and awards | Badges, trophies, commemorative plaques, and various costume jewelry, leveraging its excellent acceptance of electroplated coatings. |
Comparison with other casting materials
Section titled “Comparison with other casting materials”Compared to other common casting alloys, zinc offers specific advantages in castability, precision, and economy for small and medium parts. The following table summarizes the key differences with aluminum, magnesium, and brass.
| Parameter | Zinc Alloy (ZP5) | Aluminum Alloy (A380) | Magnesium Alloy (AZ91D) | Brass (C85600) |
|---|---|---|---|---|
| Density | 6.6 – 6.7 g/cm³ / 0.238 – 0.242 lb/in³ | 2.7 g/cm³ / 0.098 lb/in³ | 1.8 g/cm³ / 0.065 lb/in³ | 8.5 g/cm³ / 0.307 lb/in³ |
| Melting range | 379 – 388 °C / 714 – 730 °F | 565 – 650 °C / 1050 – 1200 °F | 470 – 600 °C / 878 – 1112 °F | 900 – 1000 °C / 1650 – 1830 °F |
| Minimum wall thickness | 0.25 mm / 0.010 in | 2.0 mm / 0.080 in | 2.0 mm / 0.080 in | 1.5 mm / 0.060 in |
| Typical mold life | Excellent (>500,000 shots) | Good (~200,000 shots) | Equivalent to aluminum | Poor (~20,000 shots) |
| Dimensional accuracy | Very high | High | High | Medium |
| Primary strength | Excellent castability and surface finish capability | Light weight and good temperature resistance | Best strength-to-weight ratio | Very high wear resistance |
Frequently Asked Questions (FAQ)
Section titled “Frequently Asked Questions (FAQ)”What is the full designation and standards covering the ZP5 alloy?
Section titled “What is the full designation and standards covering the ZP5 alloy?”The ZP5 alloy, also identified with the number ZP0410, is standardized under EN 12844. In the UNS system it is known as Z35531 and under ASTM B240/B669 standards it is designated as AG41A.
Is the ZP5 zinc alloy suitable for outdoor applications?
Section titled “Is the ZP5 zinc alloy suitable for outdoor applications?”Yes, the ZP5 alloy offers good performance outdoors if an appropriate surface treatment is applied. Although zinc by itself has good atmospheric corrosion resistance, it is often chrome plated or painted to protect the base material and preserve the desired aesthetic finish.
What casting process is used for ZP5?
Section titled “What casting process is used for ZP5?”ZP5 is an alloy designed for hot chamber die casting. This process is the most common for zinc due to its relatively low melting temperature (379 – 388 °C), which allows rapid injection and excellent mold filling without degrading the tooling as quickly as aluminum or brass alloys would.
Can a ZP5 zinc die casting part be welded?
Section titled “Can a ZP5 zinc die casting part be welded?”Zinc die castings are not usually welded by conventional methods due to their low melting point and high fluidity, which tend to cause collapse or porosity in the weld zone. Tin solders or specialized resins are generally used for aesthetic repairs, and mechanical fasteners are preferred for structural functions.
Why is the limitation of impurities such as lead and cadmium critical?
Section titled “Why is the limitation of impurities such as lead and cadmium critical?”The strict control of lead (0.005% max.), cadmium (0.005% max.), and tin (0.002% max.) is essential to prevent intergranular corrosion. Concentrations above the specified limits can cause expansion and embrittlement of the part over time, especially in warm and humid environments.
How does the cost of a zinc part compare to an equivalent aluminum or plastic part?
Section titled “How does the cost of a zinc part compare to an equivalent aluminum or plastic part?”For high volume production and small parts, zinc is often more economical. Although the cost per weight of material may be higher than aluminum or an engineering plastic, zinc allows faster injection cycles, longer mold life, and the elimination of secondary operations such as machining, which significantly reduces the total cost per finished part.
Sources Consulted
Section titled “Sources Consulted”- azom.com: https://www.azom.com/article.aspx?ArticleID=9562
- engineeringtoolbox.com: https://www.engineeringtoolbox.com/metal-alloys-densities-d_50.html
- steelnumber.com: https://www.steelnumber.com/en/steel_alloy_composition_eu.php?name_id=1475