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2021.4.26
What alloy is the most widely used material in the zinc die casting process? Zamak is a special being of zinc alloy. In this article, we’ll break down what is Zamak and how it’s named, the properties and its alloying elements, uses, and types.
ZAMAK, also known as Zamac, formerly represented as MAZAK, is a family of alloys with a base metal of zinc and alloying elements of aluminum, magnesium, and copper. ZAMAK is distinguished from other zinc alloys by its constant 4% aluminum content, zinc by itself doesn’t have enough mechanical properties to hold its shape, but at the same time, it has very good corrosion resistance, so that’s why we need aluminum in our alloy. With capital letters here in ZAMAK, Z stands for zinc, A stands for aluminum, MA a stands for magnesium, K stands for copper, which comes from the German language, the German names for the metals of which the alloys are composed: Zink (zinc), Aluminium, Magnesium, and Kupfer (copper). In the alloy, aluminum is used, it’s 4% and we have other relative elements magnesium and copper.
What is Zamak used for? The first one and very important one is automotive parts, more common uses are blenders, mirror frames, plumbing fittings, zipper, bathroom fixtures, handles, locks, tooling, fishing reels, ceiling fans, etc. Zamak is a popular material in die casting services due to its resistance to shocks, wear, and corrosion, high accuracy, inexpensive prices, safety, and more benefits.
How do these alloying elements affect the properties of Zamak? When talking about aluminum, if we have less than 3.5% aluminum in our alloy, less than 2.5%, the strength goes down, if we increase the amount of aluminum such as more than 4.5%, the tensile strength goes down so that means hardness increases, so in metallurgy, that means it becomes a breathable material so that’s why we keep it at the level. We need aluminium to increase the strength, it helps zinc to hold these shapes increase strength and fluidity. Secondly, magnesium is used to remove unwanted elements such as tin or lead, some elements like that to remove impurities or unwanted things. Lastly, copper is used to increasing hardness. In a word, we need an alloy other than zinc because it must be strong enough to hold its shape or it must be fluid because it is often used in die casting, this is a very important property. Zamak can be electroplated, wet painted, and chromate conversion coated well.
The most common Zamak alloy is Zamak 3. Besides that, Zamak 2, Zamak 5, and Zamak 7 are also commercially used. These alloys are most commonly die cast.
– Zamak 2: the composition is the same as that of Zamak 3, adding 3% copper in order to increase strength by 20%, which also increases the price. Zamak 2 has the highest tensile strength, hardness and creep performance out of all the Zamak alloys. Over time it retains its strength and hardness better than the other alloys; however, it becomes more brittle, shrinks, and is less elastic. Zamak 2 is easily cast, coated and machined.
– Zamak 3: the standard for the Zamak series, has the base composition for the Zamak alloys (96% zinc, 4% aluminum). It has excellent castability and long-term dimensional stability. Grade Zamak 3 also offers great finishing characteristics for plating and painting. The most commonly used alloy in North American zinc die casting.
– Zamak 5: the same composition as Zamak 3, adding 1% copper to increase strength by about 10%, hardness and corrosion resistance, but reduces ductility. Less dimensional accuracy than Zamak 3.
– Zamak 7: less magnesium content than Zamak 3 to increase fluidity and ductility, which is especially useful when producing thin-wall castings. In order to reduce inter-granular corrosion, a small amount of nickel is added and impurities are more strictly controlled.-