ZINC ALLOYS

Various types of zinc alloy parts are usually made using the zinc die casting process. All types of zinc alloy parts can be relied on for their strength and durability. Zinc alloy parts also come in a broader range of shapes and sizes since zinc alloy is more capable of producing multi-cavity complex shapes than most other metal alloys.

Zinc-based alloys are the easiest to die cast. Ductility is high and impact strength is excellent, making these alloys suitable for a wide range of products. Zinc alloys can be cast with thin walls and excellent surface smoothness making preparation for plating and painting relatively easy. It is essential that only high purity (99.99+ %) zinc metal be used in the formulation of alloys. Low limits on lead, tin and cadmium ensure the long-term integrity of the alloy’s strength and dimensional stability.

Zinc alloy’s characteristic low melting point makes it flexible enough to be used for both hot-chamber die casting machines and cold-chamber die casting machines. As a result, there are more types of zinc alloy parts manufactured and sold in the market today, with the automotive industry enjoying the largest share in the output of zinc die castings.

The zinc die casting process involves the injection of molten zinc metal alloy into dies made of hardened tool steel. Over a century ago, molten metal was squeezed into die cast dies or die cast molds to manufacture axe heads. From simple shapes, zinc alloy die casting technology has improved the process to be able to manufacture more complex shapes.

There are two processes for zinc alloy die casting:

1. The hot-chamber method and the cold-chamber method. In the hot-chamber method, a pool of molten metal is used to fill the steel die while maintaining pressure until the metal hardens in the die.
2. The cold-chamber method, on the other hand, uses separate chambers to melt and then hold the melted metal before pouring the zinc alloy into a shot cylindar and injecting them into the die casting dies.

Various metal alloys are used in the production of parts using the die casting process. Tin and lead were the first metal alloys that were used in die casting of metal printer’s types. Throughout the years, a number of other metal alloys ensued as medium for die casting parts. Among the most popular metal alloys is zinc alloy.

Zinc alloys: Zinc #2, Zinc #3, Zinc #5, and Zinc #7.
Zinc is also known as Zamak alloy: Zamak 2, Zamak 3, Zamak 5 and Zamak 7.

There are four alloys in the conventional zinc group, which are often referred to commercially as the “Zamak” alloys (an acronym for zinc, aluminum, magnesium and copper).
These alloys, with their ASTM designations, are:

• Zinc 2        ASTM AC43A
• Zinc 3        ASTM AG40A
• Zinc 5        ASTM AC41A
• Zinc 7        ASTM AG40B

Zinc alloys include the ZA Alloys (zinc-aluminum alloys): ZA-8, ZA-12, and ZA-27.