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What Is Zinc Alloy Materials？

Zinc alloy is a material composed of zinc and other elements. Commonly added alloying elements include aluminum, copper, magnesium, cadmium, lead, and titanium. Zinc alloy has a low melting point, good fluidity, and is easy to weld, braze, and process plastically. It also exhibits good corrosion resistance in the atmosphere and is easily recoverable and recyclable.Zinc is a silver-white metal with a metallic luster. It has a melting point of 419.5°C and a boiling point of 907°C. In its pure form, zinc is a relatively soft metal, with strength and hardness values greater than tin and lead but lower than aluminum and copper.

Composition of zinc alloy materials for die casting

Zinc: The primary component of zinc alloys, providing good fluidity and wettability.

Aluminum: Increases alloy strength and hardness while reducing the melting point.

Copper: Enhances alloy hardness and wear resistance, also lowering the melting point.

Magnesium: Improves alloy strength and wear resistance, and reduces the melting point.

Other elements: Such as silicon, manganese, and lead, are used to further enhance the properties of the alloy.

Zinc Alloy Die Casting Process Customized Shell

Properties and Advantages of Zinc Alloy Materials for Die Casting

- Good Fluidity:Once melted, zinc alloy has excellent fluidity, making it easy to fill molds.

- High Strength:Zinc alloy exhibits high strength, allowing it to withstand significant external forces.

- Good Wear Resistance: Zinc alloy has notable wear resistance, making it suitable for applications with high friction.

- Good Corrosion Resistance: Zinc alloy offers excellent corrosion resistance, suitable for various environments.

- Machinability: Zinc alloy can be easily machined and processed in various ways.

- High Material Utilization Rate: Die casting with zinc alloy produces near-net shapes, leading to high material utilization.

- High Production Efficiency:The die casting process with zinc alloy is fast, making it suitable for mass production.

- High Dimensional Accuracy: Zinc alloy die castings achieve high dimensional accuracy, typically reaching IT11-IT13 levels.

- Good Surface Quality: The surface of zinc alloy die castings is smooth, allowing for various surface treatments.

- Low Cost: Zinc alloy die casting is cost-effective compared to other metal die casting processes.

- Environmental Protection: Zinc alloy is environmentally friendly and harmless to both humans and the environment.

- Easy Processing: Zinc alloy has excellent processing properties, allowing it to be handled in various ways.

Classification of zinc alloys

Casting zinc alloy can be divided into two categories: die-casting alloys and gravity casting alloys. Based on their applications, they are further classified into instrument alloys, damping alloys, die wear-resistant alloys, and parts wear-resistant alloys.

Globally, there are two main standard series used for zinc alloy castings: Zamak alloys and ZA series alloys. The Zamak series includes Zamak 2, Zamak 3, Zamak 5, and Zamak 7, which are commonly referred to as zinc 2, 3, 5, and 7. The ZA series consists of ZA-8, ZA-12, ZA-27, and ZA-35. ZA-8 is mainly used for hot chamber die casting.ZA-12 and ZA-27 are only used for cold chamber die casting,due to special melting requirements.ZA-35 is generally used in gravity castings.While Zamak alloys were developed before the ZA series and are primarily used for pressure casting.

Zamak 2

Zamak 2, also known as Kirksite, is the strongest alloy in the Zamak family. However, its high copper content leads to aging characteristics over time. This includes a slight increase in volume (0.0014 mm/mm) after 20 years, along with a reduction in extensibility and filling cohesion. Although Zamak 2 is an excellent mold material, it is rarely used by die producers due to its higher creep behavior compared to other zinc alloys. Despite this, it retains high hardness and firmness even after aging.

Zamak 3

Zamak 3 is the most popular zinc alloy in North America and the preferred material for zinc die casting. It offers balanced physical and chemical properties, making it especially suitable for die casting, providing three-dimensional stability and resistance to aging. This makes Zamak 3 the standard choice for most molds. Finished products made from Zamak 3 are of high quality and are suitable for electroplating, painting, and chromic acid applications. For applications requiring higher hardness, other zinc alloys should be considered.

Zamak 5

Zamak 5 is the most commonly used zinc alloy in Europe. Due to its higher copper content, it is more rigid and firm compared to Zamak 3. This alloy offers increased strength but has reduced elasticity (continuous elongation). This reduction in stretchability can affect the metal's shape during secondary processes such as bending, tenoning, forging, and crimping, which designers need to consider.

Although Zamak 3 holds a higher market share, parts engineers often choose Zamak 3 over Zamak 5 for reinforcing parts. However, for products requiring high elongation performance,Zamak 5 is recommended. While Zamak 3 and Zamak 5 have similar creep indices, Zamak 5 exhibits stronger creep resistance. Both alloys are suitable for arc machining, but Zamak 5 is the better choice when the temperature rises above normal ambient levels and special design requirements exist for the structural bearing capacity of the part.

Zamak 7

Zamak 7 is an improved version of Zamak 3, offering enhanced die casting capabilities, ductility, and surface quality. It is often used in metal components where the molding process requires special considerations for subsequent assembly operations, such as crimping or stacking.Zamak 7 is particularly suitable for thin-wall casting and applications requiring stronger die casting for complex and fine parts. Precision in die sizes and parameters is crucial to avoid excessive sparks during the dividing tangent process. The high stretchability of Zamak 7 is evident in the production process, especially during correction grinding in secondary operations.

ZA-8 Zinc Alloy

ZA-8 zinc alloy has a significantly higher aluminum content compared toZamakalloys, as indicated by its numerical index. Originally designed for permanent casting alloys, ZA-8 produces high-quality finished products with excellent plating properties, making it ideal for decorative materials. Although its casting properties are not as good as other alloys, ZA-8 offers the best stiffness and deformation resistance among hot-tempered zinc alloys. It is the only ZA-class alloy suitable for hot chamber die casting.

ACuZinc5 Zinc Alloy

Developed by General Motors, ACuZinc5 zinc alloy has increased copper content and reduced aluminum content, resulting in improved hardness, firmness, and deformation resistance. ACuZinc5 also boasts excellent bearing capacity.

Surface Treatment Technologies for Zinc Alloy Die Casting Parts

- Electroplating:Enhances surface corrosion resistance and aesthetics

- Spraying:Improves surface corrosion resistance and wear resistance through coating application.

- Anodizing:Increases surface corrosion resistance and aesthetics by forming an oxide layer.

- Thermal Spraying:Enhances surface wear resistance and corrosion resistance by applying a thermal coating.

Surface Treatment Methods for Zinc Alloy Die Casting Parts

- Polishing:Improves surface quality by smoothing the die casting surface.

- Grinding:Enhances surface accuracy by removing material from the die casting surface.

- Ultrasonic Cleaning:Utilizes ultrasonic waves to improve the cleaning effect of the die casting.