What is Magnesium Die Casting

Extremely lightweight
Melted at a low temperature
Easily machinable
Costlier than Aluminum & Zinc
Highly reactive

Therefore, Magnesium Die Casting-

Requires a hot chamber die casting machine
Has an excellent strength-to-weight ratio
Can retain strength at high temperatures
Has bad corrosion resistance
Has good RFI and EMI shielding properties

Magnesium is known to produce the lightest structural components out of all commonly used metals. So, magnesium’s ultra-lightweight is a unique feature. Therefore, it is the main reason for its exclusive demand in some industries.

Process of Magnesium Die Casting

We have classified the magnesium die casting process into the following number of steps for easier understanding.

5 Steps for Magnesium Die Casting Process:

Die Preparation
Injection
Solidification
Ejection
Trimming/Machining

Die Preparation

Before every casting cycle, the die has to be thoroughly cleaned and lubricated. Firstly, clean the die halves with a sprayer mechanism to remove any residue from the previous cycle. Then, spray lubricant onto the die to prepare it for the next cycle.

Injection

Molten magnesium is stored in a furnace located inside the hot chamber equipment. The injection mechanism remains submerged into the furnace. There, a plunger forces the melted magnesium alloy inside the mold cavity through a gooseneck.

Solidification

Once the mold cavity has been filled, leave it alone for a specified period. Then, the casting will cool down and solidify.

Ejection

After the casting becomes solid, separate the die halves. Then, an ejection mechanism within the moving die half will eject the casting.

Trimming/Machining

Then remove the excess material from the casting using a trim die. It can be machined as well to introduce other features that were hard to implement during casting.

What are the Applications of Magnesium Die Casting?

The main scope of application for magnesium castings is where lightweight components are required. You can also use it to shield electronic components from EMI/RFI. Additionally, Magnesium is often alloyed with other materials to suit the requirements of an application.

We have described the main applications of magnesium die casting below:

Magnesium parts serve as excellent enclosures for electronic and telecommunication equipment.
You can use magnesium alloy die casting to create efficient thermal imaging camera enclosures as well.
Different transportation means always aim for lightweight parts as lighter vehicles require less power/fuel to operate. That’s why various industries use magnesium die castings as body components for automobiles, aircraft, and even bicycles.
Some magnesium alloys have enhanced ductility, creep resistance, corrosion resistance and can withstand high temperatures. Therefore, these properties make it an ideal choice for engine and transmission components.

What are the Advantages of Magnesium Die Casting?

The main advantages of Magnesium Die Casting are discussed in detail below:

Extremely Lightweight

Magnesium’s specific gravity is only 1.74. Whereas aluminum has about 2.55 and Iron has about 7.5. Therefore, magnesium is almost 35% lighter than aluminum and 75% lighter than Iron. Consequently, it is considered one of the most lightweight structural metals.

Easy to Machine

Magnesium die cast parts are easy to machine. So, they require less time and cost. It could be a good choice when dealing with a die casting project that requires too much secondary machining.

Good Castability

Magnesium alloys are known for their castability. The high fluidity of magnesium alloys makes them easy to cast. So, intricate features and thin walls are easier to implement with magnesium alloy casting.

Excellent Shielding Properties

Magnesium parts have exceptional EMI/RFI shielding properties. So, magnesium enclosures can protect electrical components from electromagnetic radiation. Thus, this makes it very important for certain applications.

What Magnesium Alloys are There in Die Casting?

Magnesium alloy composition mainly consists of the following elements,

Aluminum
Zinc
Silicon
Rare Earth
Manganese

Here, AZ91D alloy is more commonly used for die casting magnesium alloys. The first two letters of the alloy refer to the major alloying ingredients. For instance, the AZ91D alloy has 9% aluminum and 1% zinc.

Normally, magnesium has bad corrosion resistance. The high percentage of alloying elements, especially aluminum, improves its mechanical properties, corrosion resistance, and castability. Decreasing aluminum content would compromise these properties but would increase the ductility.

There are different variations of magnesium alloys available in the market. Which one you need depends on your product’s application. The commonly used magnesium alloy includes,

AM50A
AM20
AM60B
AS41B
AE42, etc.

Here, magnesium die casting companies use AM50A, AM20, and AM60B alloys, when they need to achieve a reasonable toughness, ductility, and impact resistance. They use the AS41B and AE42 alloys when focusing on better strength at high temperatures, ductility, and creep resistance.