Die Cast Aluminum Alloys: The Ultimate FAQ Guide

This guide explores everything you need to know about die cast aluminum alloys.

So, before choosing any aluminum alloy for die casting, read this guide.

Which Grades Of Aluminum Alloys Are Suitable For Dies Casting?

A380 Aluminum Alloy

This is the most commonly used and popular Aluminum alloy for die casting. It is preferred because of its strong mechanical and physical properties required for die casting.

Such properties include its resistance to corrosion, its lightweight and the fact that its strength can withstand very high temperatures.

Dimensional stability is also retained by A380 Aluminum Alloy despite having thin walls and having complex shapes.

The A380 Aluminum Alloy also has a very good thermal conductivity while still offering a high electrical conductivity.

  1. Benefits of die cast A380 Aluminum Alloy
  • Lighter parts can be die cast with a variety of surface finishing options.
  • It has the highest operating temperatures compared to other aluminum die cast alloys.
  • It is resistant to corrosion.
  • Its application can be in various industries due to its high dimensional stability retention.
  1. Applications of die cast A380 Aluminum Alloy
  • Used to manufacture various products such as hand tools, electronic equipment chassis and engine brackets. Others include power tools and household furniture.

Product Made From A380 Aluminium Alloy

A Product Made From A380 Aluminum Alloy

A383 Aluminum Alloy

A383 Aluminum Alloy is the most widely used option utilized by die casters.

When intricate components that need precise characteristics of die-filling, the A383 Aluminum Alloy is the most preferred in forming them.

It is very strong at very high temperatures and has a very little chance of cracking under intense heat in as much as it has dissimilar properties to the A380 Aluminum Alloy. It is called ADC12.

  1. Benefits of die cast A383 Aluminum Alloy
  • Its corrosion resistance is very high hence its shelf life is improved
  • It is lightweight with great fluidity thus easing the casting process
  • It contains exceptional mechanical and thermal properties
  • Has a sound dimensional stability
  1. Limitations of Die cast A383 Aluminum Alloy
  • Compared to A380 Aluminum Alloy, it is not as durable
  1. Applications of die cast A383 Aluminum Alloy
  • Electronic equipment
  • Motor vehicle components
  • Home appliances
  • Power tools
  • Communication equipment
  • Electric vehicles

Motor Vehicle Equipment Made From A383 Alloy

Motor Vehicle Equipment Made From A383 Alloy

A360 Aluminum Alloy

This type of aluminum alloy is hard to die cast compared to A380 meaning die casters avoid it.

Depending on casting abilities and needs, the A360 Aluminum alloy has very good strength at high temperatures.

  1. Benefits of die cast A360 Aluminum Alloy
  • It has a very high corrosion resistance
  • At elevated temperatures, it has superior strength
  • Better ductility
  1. Limitations of die cast A360 Aluminum Alloy
  • Difficult to cast
  1. Applications of A360 Aluminum Alloy
  • Manufacture of vehicle oil pans
  • Motor vehicle controller shells
  • Motor shells
  • 5G communication boxes
  • LED lamp housing

A360 LEDLamp Housing

A360 LED Lamp Housing

B390 Aluminum Alloy

This aluminum alloy has a very high hardness and a good resistance to wear.

Its energy is temperately low embodied among all the die cast aluminum alloys.

  1. Benefits of die cast B390 Aluminum Alloy
  • It has a very high hardness
  • Has a very good wear resistance
  1. Limitations of Die cast B390 Aluminum Alloy
  • Has a lower density
  • Its thermal expansion coefficient is small
  • It is difficult to machine
  1. Applications of Die cast B390 Aluminum Alloy
  • Manufacture engine pistons and brakes
  • Compressors

B390 Die Cast Aluminium Alloy

B390 Die Cast Aluminum Alloy

A413 Aluminum Alloy

It is a special type of die cast aluminum alloy that majorly exhibits an excellent pressure tightness property.

  1. Benefits of Die cast A413 Aluminum Alloy
  • Good fluidity
  • Excellent pressure tightness
  • High hot tear resistance
  • Good castability
  • Good machinability
  • High specific strength
  • High corrosion resistance
  1. Limitations of Die cast A413 Aluminum Alloy
  • Its cost is very high
  • Contains high level of impurities
  1. Applications of Die cast A413 Aluminum Alloy
  • Used in the aerospace industry to manufacture corrosion resistant materials which are strong and lightweight
  • Used in the manufacture of marine industry products
  • They make up parts of most bicycles
  • They form parts of the alloy metals in the automotive industry
  • Used to manufacture gas and air cylinders due to their high resistance to corrosion and tensile strength.

A356 Aluminum Alloy

Die cast Aluminum A356 Alloy is a very common material in die casting. It comes in three brands namely A356.0; A356.1 and A356.2

  1. Benefits of Die Cast A356 Aluminum alloy
  • It has good castability
  • It is lightweight
  • Contains excellent mechanical properties
  • It has excellent weldability characteristics
  • Very good corrosion resistance
  • No hot cracking tendency
  • It has a small linear shrinkage
  • Good corrosion resistance
  1. Applications of Die Cast A356 Aluminum Alloy
  • Used to manufacture flywheel castings
  • Impellers and blowers with high velocity
  • Space and airframe structures with very high strength
  • Truck chassis parts and high strength machine parts
  • Pump bodies, automotive transmission cases and oil pans

A356 Aluminium Cast Pump Housing

A356 Aluminum Cast Pump Housing

A357 Aluminum Alloy

This die cast aluminum alloy is applied in situations that require a combination of pressure tightness and high corrosion resistance.

  1. Benefits of Die Cast A357 Aluminum alloy
  • High strength
  • Ductility
  • Resistant to corrosion
  • Less sensitive to drop in temperature
  1. Applications of die cast A357 Aluminum Alloy
  • Used in the production of cast automotive components like frames and brackets
  • Used in semi-solid processes
  • Manufacture of pump and valve components
  • Used in the making of impellers
  • Building housing structures

K Alloy / A304

This is a die casting alloy that is patented and has been a game changer for manufacturers and die casters.

This is because surface finishing processes like painting, chromating and anodizing are eliminated.

The elimination of such expensive procedures saves a lot of time and money.

The K Alloy / A304 is designed in such a way that components are protected from damages from the environment that inhibit their performance.

  1. Benefits of Die cast K Alloy / A304
  • Excellent corrosion resistance
  • High elongation properties hence making it sturdier
  • Very good thermal conductivity which improves cooling
  • It has a high polish superior finish quality
  • No extra polishing or surface finishing required
  • Better flowability hence spreads precisely I the die cavity
  • Less shrinkage compared to other die cast aluminum alloys
  1. Applications of Die cast K Alloy / A304
  • Famous for manufacturing vehicles under harsh engine environments with temperatures constantly changing.
  • Applied in the military to make antennae radios and drones and to assist essential instruments withstand corrosion and extreme damaging elements.
  • Recreational vehicles, boating components and equipment and fishing rods.
  • It is suitable for outdoor and indoor lighting cases i.e. flood lights, street lighting or stadium lighting.
  • It provides electrical housing for components such as relays, capacitors, diodes, integrated circuits etc. and shields them from extreme environmental conditions.

Which Parts Can You Make From Die Cast Aluminum Alloys?

Die casting of Aluminum alloys has been known to produce complex designs not effectively produced by either machining or extrusion.

  1. A perfect example is the manufacture of engine blocks and other complex parts like transmission blocks.
  2. Recreational vehicles and their automotive parts are also made from Die Cast Aluminum alloys. They range from the counter mounts to the chassis.
  3. Firearms require reliable parts that have extreme accuracy. Die cast Aluminum alloys are used to create such in addition for use in law enforcement institutions and the military.
  4. Hospital and medical equipment require accurate and precise components. Die Cast Aluminum Alloys can satisfy this need efficiently.
  5. The lighting and telecommunication industry need electrical closures that offer crucial weatherproofing tools applied in many situations. Die Cast Aluminum Alloys can be used to custom make such enclosures for any application.
  6. Industrial equipment such as air compressors and pumps are created from Die Cast Aluminum Alloys.

What Are The Recommended Surface Finish For Die Cast Aluminum Alloy?

Chrome Plating

This is a very expensive surface finish method due to the labor involved. This method gives the die cast aluminum alloy a mirror-like finish.

In the automotive industry, a bright chrome is more commonly used. Satin chrome is also used as it produces a pearlescent appearance.

Chromate

This is an economical bulk procedure conversion coasting. It is a type of chemical conversion coating whereby a chemical reaction takes place on the die cast aluminum alloy.

The metal surface is transformed into a protective layer by the chemical reaction. This type of surface finish comes in an array of colors.

Anodizing

This is an electrochemical procedure that changes the die cast aluminum alloy surface into a decorative, long-lasting anodic finish that is resistant to corrosion.

Application of this oxide is not like paint or plating on the surface but it is integrated wholly with the die cast aluminum alloy.

This means that it does not peel. It is a very affordable option.

Powder Coating

This is a dry coating procedure that is mostly applied in die cast aluminum alloys that are used to manufacture industrial equipment.

Using an electrostatic process, dry powder is applied on the surface to form a powder coating.

Curing is done at very high temperatures hence it has a very tough finish. It is also resistant to scratch and ding.

E-coat

This process is a form of dipping wet paint finish where electrical current is used to attract paint to the die cast aluminum alloy surface.

It is similar to metal plating but e-coating uses organic paint for the finish instead of particles of metal in the dipping baths.

E-coat can be used alone or as an undercoat for other coatings like powder coat. It usually serves a functional purpose as opposed to decorative.

Bright Nickel

This is a finishing process whereby a layer of bright nickel is plated over a plating of semi-bright nickel on the surface of the die cast aluminum alloy.

A thin chrome plating application is then used to cover it.

This finish tends to be brittle therefore not recommended for parts that may be crimped or bent just after plating.

Polishing

This is a finishing process whereby the surface of the die cast aluminum alloy is smoothened by using an abrasive.

It is generally done to increase reflectivity, inhibit contamination improve the appearance of the die cast aluminum alloy.

It acts as the die cast aluminum alloys protective sealant thus improving its durability. It also reduces the wear and tear and corrosion of the die cast aluminum alloy.

Painting

A natural coating on the die cast aluminum alloy can be achieved using paint.

When paint is applied to a pre-treated surface, the die cast aluminum alloy will have a great look and can also be customized to suit one’s brand.

Teflon Coating

Teflon coatings can be applied on the surfaces of die cast aluminum alloys. The surface is roughened in order to obtain optimal adhesion before the coating is applied.

With the exception of mentioned instances, a primer coat is required for these coatings.

Electroless Nickel Plating

A coating of Nickel is deposited on the surface of the die cast aluminum alloy using an auto-catalytic reaction.

Current is not necessarily passed through the solution for deposits to form unlike in electroplating.

This surface finish technique helps to prevent wear and corrosion. Its advantage is that it eliminates power supply issues and it is flux-density free.

Despite the workpiece geometry, an even deposit on the die cast aluminum alloy surface can still be achieved easily.

Chem Film

This type of surface finish is also called conversion coating and is a chemical conversion coating. The surface of the die cast aluminum alloy experiences a chemical reaction.

The alloy surface is then transformed into a protective layer by the chemical reaction.

It provides the die cast aluminum alloy with corrosion protection while leaving a base on the alloys surface for organic coatings.

It also protects the alloy from loss of electrical conductivity.

Chrome Finish Of Dies Cast Alluminium Alloy

Chrome Finish Of Die Cast Alloy

How Do You Choose Mold For Die Casting Aluminum Alloy?

Molds are manufactured from very high quality and heat-resistant steel and each mold is specifically designed for each project carried out.

This ensures that each individual component is created with precise accuracy and has repeatability.

The mold design should be considered before anything else.

The design tends to have an impact on the uniformity of a product, its shape, quality and configuration during the die casting process.

Inferior quality products and material corrosion maybe the impact of having a mold with improper specifications.

An effective mold design will ensure efficiency is improved and production time reduced.

What Are The Common Defects In Die Cast Aluminum Alloys?

The defects in die casted aluminum alloys can be categorized into two; internal and superficial. Internal defects are not easy to find and may result in weakening the structural resistance of the component.

Superficial defects are casting defects that are visible on the surfaces of die cast aluminum alloys.

The defaced the surface of the component and reduce its aesthetic quality.

Internal defects

a)      Gas porosity

Turbulences are generated when the fluid moves at high speed on the filling phase. The turbulences are composed of various gases including air.

If the concentration of gas inside the casting is not uniform, cavities will be formed by air bubbles.

The effect will be the weakening of the components resistant sections.

Depending on the type of entrapped gas in the filling stage, the cavities may be opaque or shiny and they are rounded. Lubricant, air and water each have different types of cavities.

b)      Shrinkage Porosity

These defects occur during the cooling and solidification stages of die casting aluminum alloys.

They occur when the material shrinks and this is the reason why they are extensively spread in substantial parts.

Material have a tendency of moving around colder zones.

Due to the variations in temperature between the core and casting surface, the cavities are focused inside the part.

c)      Inclusions

These are material discontinuities which can be non-metallic or embedded intermetallic phases inside the matrix of the metal.

The various forms of inclusions include liquid droplets, solid articles or films in molten die cast aluminum alloys.

The alloying materials and the value of charge are the determinants of the type and amount of inclusions inside the melt.

Inclusions that are commonly found in die cast aluminum alloys include borides, non-metallic compounds, carbides and oxides.

Superficial Defects

a)      Lakes

These defects occur mostly in components that are aesthetical. The different times of solidification of the die cast aluminum alloy is the cause of these defects.

This is because they generate a separate skin on the alloys surface.

The affected area looks fine grained and differs from the rest.

b)      Cold Laps

These are the most common die cast aluminum alloys defects found. Their major cause is very low temperatures and irregular flows.

This defects encompasses a varied selection of defects including shortage of material and flow marks.

Alloys will end up with substandard surface quality or worse still it could end up incomplete depending on the rate of defect.

c)      Blisters

Air within the machine and mold becomes compressed in the mold filling process.

A single part is removed using a vacuum valve from the casting or it overflows.

Homogenous distribution can be used to dissolve the air that remains in the component within the melted metal.

In the event that the component extra operations of high temperatures, blisters are not visible but will diminish the components strength.

High temperature processes like powder painting have an expansion of gases within the casting that expand hence bubbles on the surface are generated.

d)      Lamination

This defect by extension falls under the category of cold laps. Their major cause is the overlapping of two layers which eventually are separated when filling is done.

Detecting these defects is near impossible but pre-finishing operations such as sand blasting expose them.

Aluminum layers’ experience lifting arising from casting and inserts impact.

These layers tend to hide fluids and die casting process dirt such as oil or lubricant between them.

Such substances worsen the galvanization or painting outcome when they manifest during surface treatment.

e)      Cracks

This is the breakage of die cast aluminum alloy brought about by stress within and outside the alloy.

The first cracks become visible when solidification and cooling takes place.

The die cast aluminum alloy cannot naturally shrink because of its cavity geometry. This leads to cracks that are brought about by residual stress.

The second cracks arise from external forces acting on the die cast aluminum alloy.

Such forces occur when parts are being ejected from the mold or during the cutting phase.

Do Die Cast Aluminum Alloy Require Heat Treatment?

Heat treatment can be used to modify the property profile of a lot of die cast aluminum alloys in a directed method.

This is applicable to pressure die casting alloys, sand die casting alloys and gravity die casting alloys.

Die cast aluminum alloys manufactured by conventional die casting are bound by limitations with regards to solution annealing.

This is due to the effects of blistering brought about by extreme temperatures.

The lack of knowledge of the range of heat treatment options often leads to poorly defined and incorrect parameters, and improper utilization of the potential of hardenable alloys.

The determinant factors for the selection of the type of heat treatment include the intended purpose, the process of manufacturing and the boundary conditions related to production.

Heat treatment generally leads to an increase in the cost of the end product of die cast aluminum alloys and the turnaround time.

A Heat Treatment System For Die Cast Aluminium Products

A Heat Treatment System For Die Cast Aluminum Products

If you have any questions or inquiry about die cast aluminum alloys – contact us now.

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