Zamak 3 is a zinc alloy. It casts easily. It’s strong and stable. Around 4% aluminum helps it flow. This makes detailed parts possible. Cars, electronics, and hardware use it. Softness means you need carbide tools to machine it. Coatings fight corrosion.

This article describes Zamak 3 capabilities, its working, key variants, and why it is chosen for efficient and precision projects.

Definition and Overview of Zamak 3

In Zamak 3, aluminum, copper, and magnesium are also present, including the main element of zinc. It has several features of corrosion resistance, wear resistance, strength, and machinability. That is beneficial for most of the industry, especially for industrial.

Dendritic Structure and Phases of Zamak 3

The zinc-based alloy Zamak 3 has certain qualities. Its microstructure is unique. The formation of a dendritic structure occurs during its solidification phase.

There are two main phases (alpha and beta) in this structure. The alpha phase consists of rich zinc, while in beta, there is more aluminum. These phases dictate the alloy’s strength and durability.

Composition and Properties of Zamak 3

A. Chemical Composition

Percentage Ranges

The alloy of Zamak 3 has primarily zinc. It is composed of other alloy contents. There is, for example, 3.5%–4.3% aluminum and 95.6%–96.5% zinc. It includes magnesium (0.02% — 0.05%) and copper (0.10% — 0.25%) as well.

Role of Each Element in Zamak 3

Zinc die casting works as the base element for the Zamak 3 alloy. It gives its structural integrity. Aluminum contributes to fluidity improvements. It makes the alloy much stronger, forming a solid solution.

The magnesium alloy refines the grain structure. It creates better hardness and lessens brittleness as a result.

To compete with high-stress conditions, the addition of copper increases the tensile strength and wear resistance of Zamak 3.

If the lead, cadmium, and tin (impurities) are there (more than 0.005% each) in the alloy, it can affect the mechanical strength. That leads to cracks or corrosion.

B. Physical Properties

Thermal Expansion Coefficient

Zamak 3 has around 27.4 µm/m°C thermal expansion coefficient. That’s why you can expand the alloy up to 0.0274 mm for every 1°C temperature. Especially in a 1-meter-long workpiece.

Electrical Conductivity

Zamak alloys have electrical conductivity. That is around 28% of the International Annealed Copper Standard (IACS). It is, however, less conductive in comparison to pure copper. But you can use them for components like connectors.

Specific Heat Capacity

There are 420 joules of heat capacity in Zamak 3. Specifically, this aids in improving the 1 kg alloy temperature up to 1°C.

I am running a few minutes late; my previous meeting is running over.  Zamak 3 melts at 385 °C. It also has a latent heat of fusion of 113 kJ/kg.

When the temperature goes up 150 °C, this alloy is more likely to lose its strength.

However, it maintains dimensional stability and suits low- to moderate-temperature parts.

C. Mechanical Properties of Zamak 3

Stress-Strain Curves

The image shows two conditions of the stress strain curve of zamak 3 ingots. One is as-annealed (softened) and the other one is solution-treated (SFT).

The as-annealed shows 143 MPa yield strength. When it undergoes SFT, it gets improved and reaches 212 Mpa.

Another reason for these improvements is the redistribution of aluminum and zinc phases during heating.

Fatigue Strength

After completing 10 million cycles, Zamak 3 reaches 50 MPa fatigue strength. This also means the alloy can handle multiple or repeated stresses around 50 MPa without failure.

Impact Strength

Impact strength around 48 J/cm² enables the alloy to absorb sudden shocks. There is 80 to 100 HB (hardness). To check this, manufacturers press a 10 mm steel ball into the ingot under a 500-load

Advantages of Zamak 3

1.   High Strength-to-Weight Ratio

Zamak 3 has a high strength-to-weight ratio. This is because of its tensile strength and the presence of a density of 6.6 g/cm³. This also impacts its weight, making it stronger than certain plastics. It is also lightweight yet more durable than steel.

2.   Corrosion Resistance

This alloy corrodes less because there is a protective layer of zinc oxide. This layer occurs on its surface and avoids oxidation.

That is also effective in humid or mildly acidic conditions. So they offer long-term durability as a result.

3.   Excellent Castability

You can use Zamak three alloys to manufacture very thin wall parts. They can contain complex shapes and could be as thin as 0.5 mm.

It produces parts with very good surfaces. Because of this, the parts need minimal machining or postprocessing. That ultimately saves production time and labor costs.

4.   Vibration Dampening Properties

Zamak 3 effectively reduces vibrations. This means it can absorb up to 30% more energy. That is better than steel.

This feature works by reducing noise and wear in things such as moving parts. Therefore, machinery and automotive systems choose it.

Applications of Zamak 3

Automotive Industry

The automotive industry usually chooses Zamak 3 to manufacture their parts. For instance, fuel system components, door handles, and gear housings.

Furthermore, it has less weight. That alternatively increases fuel efficiency. The corrosion resistance property suits in harsh environments.

Aerospace Industry

Manufacturers make non-critical structural parts using this ingot. For instance, brackets and fasteners.

It dampens vibrations, which lessen stress and increase safety. This feature is helpful in aircraft systems.

Electrical Industry

Zamak 3 is used in the electrical industry to make connectors, switches, and housings.

It has good electrical conductivity and can handle sensitive gadgets. That’s because of its electromagnetic interference shield.

Hardware Industry

The hardware sector uses Zamak 3 for locks, hinges, and decoration pieces. It makes parts with detailed designs because of its castability. The corrosion resistance enhances durability in outdoor objects.

Shielding Applications

In electronics closures, Zamak 3 forms EMI shields. It protects sensitive parts from electromagnetic waves. The industries include telecommunications and computing.

Equivalent Materials and Substitutes

Zamak 3 Equivalent Materials

Comparison of Zamak Alloys:

All other zamak alloys, including zamak 2, 3, 5, and 7, contain different compositions and attributes.

• Zamak 2 includes higher alloying copper of 2.7% to 3.3%. Therefore, they offer greater strength but fewer ductility.
• Zamak 3 has aluminum, magnesium, and copper in varying ranges. It gives a balanced strength and castability.
• There is 0.75%-1.25 copper content in Zamak 5. That’s why the alloy offers good wear resistance.
• Zamak 7 resists corrosion well because of a lower amount of 0.005% — 0.02% magnesium.

Substitutes

Aluminum:

There is 324 MPa tensile strength in Aluminum (A380). The density is around 2.71 g/cm³. Lightweight and affordability are their benefits. Best suits for automotive and aerospace.

Brass:

The tensile strength of brass C36000 is 469 Mpa. Density ranges from 8.5 g/cm³. It is strong and resists corrosion well. However, it costs more and is heavier. Used for plumbing.

Bronze:

310 mpa is the tensile strength of bronze C93200. It has an 8.8 g/cm³ density. This alloy is expensive and dense but resists wear in parts like bearings.

Among these substitutes, zamak 3 has less weight compared to brass and bronze. However, it is heavier than aluminum. You can choose them as an affordable choice for manufacturing general applications. Meanwhile, the subtrees suit certain needs.

Machining and Fabrication

Cutting Speeds and Feed Rates:

Metalworkers machine Zamak 3 ingots, applying cutting speeds of 100–150 m/min. The feed rate fluctuates between 0.05 and 0.15 mm. These parameters work to remove parts during ejection.

Tool Materials

Tool material must be carbide or high-speed steel (HSS). These are recommended because of their machinability for Zamak 3.

They meet important durability and give the exact sharpness. So that the tool handles ingot softness and resists wear.

Machining Challenges

The softness feature of Zamak 3 causes tool wear and burr formation. This is the primary challenge that Zamak 3 casting faces in machining.

Optimization of tooling and designs results in better outputs. Such as maintaining cooling or cutting aspects.

Joining Techniques

You can assemble different parts of Zamak 3 using soldering techniques or adhesive bonds.

Also, there is no such need for welding. Because it can weaken the metal and cause structural issues.

Corrosion Resistance and Surface Treatment

1.   Corrosion Resistance

Electrochemical Mechanisms

Zinc oxides when it is exposed to moisture or oxygen. That’s become the reason for corrosion in Zamak 3 via electrochemical reactions.

Environmental Factors Affecting Zamak 3:

Corrosion issues increase in Zamak 3 if faced with environmental factors like humidity, pH levels, and exposure to salts.

2.   Surface Treatment Zamak 3

Chromating:

Chromating technique is an effective way to protect parts from corrosion. In this. A chromium oxide layer occurs.

This is a kind of thin coating of 0.5–2 µm. However, there is an environmental concern because of hexavalent chromium.

Anodizing:

The anodizing process creates a thicker oxide layer using electrochemical techniques. Its benefits include enhanced corrosion resistance and better surface hardness.

This process, however, needs proper control over voltage and electrolyte composition.

Painting:

This process applies a primer and paint layer to the part. There are necessary steps to be followed before painting. Such as cleaning and phosphating.

So the layers stick well. A part after paint coating gets a protective shield and a beautiful look. But paint can be peeled off over time.

Powder Coating:

Manufacturers use electrostatically charged powder to powder coat parts. It is cured properly to ensure adhesion. The parts get better durability and thicker layers with less environmental impact.

Conclusion:

Zamak 3 alloy is especially used in general applications. It is a versatile ingot that gives excellent castability and strength and resists corrosion. Because of their balance attributes, industries like automotive, aerospace, electrical, and hardware use them.

Tool material, surface treatments, and machining parameters are important in case of increasing alloy performance. These are also cheap and durable metals and are becoming the reason for various industrial uses.