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2020.11.23
When it comes to the material options for zinc die casting, we have to mention Zamak 3 alloy. Zamak goes by many different names based on standard and/or country, it is a versatile metal in die casting and lots of other industries, in this article, we’ll outline the Zamak 3 chemical composition, properties, advantages, and uses in die casting.
Zamak 3 (Zinc Alloy 3) is the most common Zamak alloy and a popular die casting material. Zamak, also known as ZAMAK or Zamac, a family of alloys with zinc as the base metal and aluminum, magnesium, and copper as alloy elements. “Zamak” is the acronym of a German game for the alloys that are composed of Zink (zinc), Aluminum, Magnesium, and Kupfer (copper). Zamak alloys are part of the zinc-aluminum alloy family, the constant 4% aluminum composition distinguish them from other alloys. The use of 99.99% pure zinc metal solved a big problem of early zinc die casting materials: zinc pest, which is due to impurities in the alloy. The excellent physical and mechanical properties, dimensional stability and great castability makes Zamak 3 commonly used in zinc die casting, more than 70% of zinc die castings in North America are made from Zamak 3.
Other forms/names of Zamak 3
Zamak 3 has the base composition for the Zamak alloys (96% zinc, 4% aluminum), it is the standard for the Zamak series of zinc alloys, all other zinc alloys are compared to it.
Zinc: Balance
Aluminum: 3.5-4.3%
Copper: 0.25%
Magnesium: 0.02-0.05%
Iron: up to 0.1%
Lead: up to 0.005%
Cadmium: up to 0.004%
Tin: up to 0.003%
Physical Properties of Zamak 3
Density of Zamak 3: 6.7g/cm3 (0.24 lb/in3)
Melting range: 381 – 387 ℃
Thermal conductivity: 113 W/mK
Electrical resistivity: 6.37 μΩ-cm at 20 °C
Coefficient of thermal expansion: 27.4 μm/m-°C
Coefficient of friction: 0.07
Die Shrinkage: 0.007 in/in
Mechanical Properties of Zamak 3
Hardness: 97 Brinell
Yield Strength (0.2% offset): 208 MPa or 30200 psi
Ultimate Tensile Strength: 268 MPa or 38900 psi
Modulus of Elasticity: 96 GPa or 14, 000, 000 psi
Shear Strength: 214 MPa or 31000 psi
Impact Strength: 46 J (56 J aged)
Elongation at fracture: 6.3% (16% aged)
Zamak is widely used in automotive parts, furniture accessories, appliances components, faucets and taps, shower hinges, handles, valves and pneumatics, toys, ornaments, clothing, mechanical parts, and more industries and applications, different Zamak alloys are suitable for different uses. When it comes to zamak 3 alloy, it’s usually considered the first choice of zinc die casting.
The Zamak die casting process is to melt the Zamak ingots in a 420°C furnace adjacent to the die-casting machine, and then inject the alloy into the cast mold. Why use Zamak 3 in die casting?
Advantages of Zamak 3 in Die Casting
– High fluidity and low melting point (save energy)
– Resistance to corrosion, impact, and wear
– Allows low tolerances, high accuracy, high complexity of castings
– High durability of the molds for Zamak die casting, longer service life than for aluminum casting
– Easy to use, fast cycle.
– Versatility and in various finishing process or surface treatment like plating and painting
– Suitable for small or large batch production
– Superb castability and constant dimensional stability
– Do not disperse any harmful substances in the air or the environment
– Recyclability, die-cast Zamak parts are recyclable
– Affordable price, the cost is lower than many other die casting alloys
– Excellent damping capacity and vibration attenuation