Magnesium Die Casting: Everything You Need to Know
Because of the excellent features, aluminum die casting is the favorite process among all for most companies and manufacturers. And we got many articles and blogs about aluminum die casting on our website. In this article, We are going to go over magnesium die casting in particular.
What is Magnesium Die Casting?
Magnesium die casting is a process where magnesium alloys are melted and forced into a mold cavity where it takes the shape of the mold or final design.
The process of aluminum die casting and magnesium die casting is almost identical. The main differences are the molten metal and the temperature required. Otherwise, the process remains the same.
Magnesium is one of the finest and easiest tools for machining works. It gives you extra ordinary performance on machining activities like punching, drilling or milling. It takes a shorter time to do so as well.
Manufacturers are able to apply strong cutting at high speed, so the process is faster than other metals. Which ensures that less machine hour is needed and the cost of machining is less.
Machining magnesium can be an affordable option as it can save the cost in various ways:
- Less machine hour needed
- Doesn’t require large working space
- Easily machined and less power consumed
- Minimum workforce and equipment needed
Magnesium alloys are lightweight and well-known metal alloys. Primarily they are made with magnesium. However, they might have aluminum zinc or other metals in them to increase the mechanical and physical properties.
Their strength to weight ratio is comparable with steel alloys. One other major characteristic of this alloy is that it has a lower density and higher specific modulus.
These alloys are good when you don’t need great strength and a thick, light form metal is necessary.
There are two main groups of magnesium alloys. Cast alloys and wrought alloys.
They are made by pouring the molten metal into a mound and extracting the hardened final parts. Common cast alloys consist of magnesium and zinc as their primary components. However, they also include less than 10% of aluminum and other metal substances as well.
AZ91D, AM60B, and AM50 are the most common magnesium alloys for die casting. But other than that there are other a large number of cast alloys are available such as AZ63, AZ81, AM60, ZK5, HZ32, QE22, QH21, WE54
Unlike cast alloys, wrought alloys are best used for mechanical applications. When you need magnesium for extrusion, forging or other mechanical works like this, wrought alloys are the best option for you.
In this type, aluminum is also present significantly along with magnesium and zinc. This type is also divided into two sections, heat treatable and non heat treatable alloys.
Some of the wrought alloys are AZ31, AZ61, AZ80, Elektron 675, ZK60, M1A, HK31, HM21, ZE41
The process of magnesium die casting is almost identical to aluminum die casting. As we’ve covered the entire process in detail there, I am not going to cover it here.
However, it requires less temperature to melt the metal compared to aluminum die casting or zinc die casting. As it’s lighter than aluminum, the final parts will be lighter as well. The magnesium die casting process can cast thin walls and complex structures with smoother surfaces.
How Strong is Magnesium
Magnesium is an extremely lightweight material with fair good strength. As there are many grades of magnesium and magnesium alloys are available, the strength of the material truly depends on the condition and composition of the material.
Magnesium alloys do have a wide range of uses and applications. Because it offers some great features. They’re great for high levels of machinability, cast ability and strength.
Major industries that uses magnesium die casting parts:
Automotive industry is the primary user of these parts. The reason is obvious, lesser weight. They can be found in brakes, clutch and transmission areas.
For them, weight is the number one deal maker or deal-breaker. So wherever possible the aerospace industry looks for strong, but most importantly lightweight metals to use. Landing wheels, gearbox housing, and rotor boxings are some examples of magnesium die casting parts used in aerospace.
People who need parts for their high-speed machinery, like textile machines. Magnesium parts can be an option for them.
Magnesium products are heavily used in electrical components and appliances. We have them in our cell phone and computers as well.
For some mobile equipment in the medical industry, magnesium is used.
Magnesium Die Casting vs. Aluminum Die Casting
Both these metals bring unique properties to the parts and equipment and have their own set of demands. Their features and benefits make them demandable for their uses. Both seem similar from the outside, the question is, can you substitute one with another?
No. Because although they seem to have similar functionalities there are some core differences that make them perfect for their own uses.
Here are some major differences between them. This is to help you understand why they are better for their own applications and which one to choose for your own projects.
Magnesium alloys solidify faster than aluminum and it has a shorter die life comparably. On the physical site, Aluminum is heavier but more stable than magnesium. If you consider the finishing, aluminum doesn’t need finishing as much as magnesium. As it requires special treatments and coating prior to being used.
Magnesium’s strength to weight ratio is satisfactory, however, generally speaking, aluminum parts are stronger, more stable, and have a great amount of durability.
Although the magnesium die casting process is faster than the aluminum die casting process, aluminum remains the cheapest of all.
Magnesium requires less time in melting and ejecting from the mold, but the cost of the aluminum is less per cubic inch. Which makes it cheaper than the other.
Magnesium is lighter than aluminum and has a smoother surface after die casting. It can cast thin walls and complex structures. Using magnesium for your projects can reduce the weight of your machine or you can have very thin walls.
Although it saves money on the machining, in general, magnesium metal is more expensive. So for casting, and if you’re ordering bulk items, you want to consider the cost-effectiveness of this material.
Aluminum die casting parts are widely used and accepted metal that can be used for almost any metal application. The main difference is that you get more durable, stable, and stronger parts when you choose aluminum for your projects.
if you’re looking for a strong metal that won’t bend in high stress you’ll want to go with aluminum. On top of that, it will cost you less.
Magnesium vs. Steel
If you compare steel with magnesium, the first thing to be considered is the weight. Magnesium is about 75%lighter than the steel. It also has better tooling capacity and high heat conductivity.
Die casting magnesium is way cheaper than steel. It’s because of the low temperature it requires and longer die life than steel.
Magnesium vs. Zinc
Zinc has an even lower melting point and longer die life than magnesium. This means casting zing is cheaper than casting magnesium. In addition, zinc doesn’t require special treatments or coatings, which saves the buyer’s cost as well.
Corrosion is a common disadvantage among most metals. However, magnesium corrodes very rapidly.
Why does Magnesium Corrode So Fast
The reason behind it corrodes so fast is a couple of ingredients present in the metal that accelerates the corrosion. These items are sulfates, iodides, Chlorides and bromides.
How to Prevent
Because of the fast corroding nature, magnesium is often avoided in automobiles and various other applications. However, when you’re using magnesium parts, you need to make sure they don’t corrode fast. There are certain measurements that can be taken during production and while using as well.
Magnesium requires special treatments and coatings, it’s recommended to apply a protective coating to make it safe from corroding fast. Protective cold sprays and corrosion inhibitor chemicals are other options that you can consider as well.
How to Clean Corrosion from Magnesium Surface
When the prevention or protective coating fails and the metal begins to corrode, its best if the corrosion has been identified in the initial stage of the corrosion. So it’s easier to clean and repair the parts.
For cleaning, first protect the surrounding areas, so the corrosion does not spread. Now start to clean the corroded area by cleaning any oil or dust and strip out the paint.
Then you’ll need to apply abrasive and start sending the affected area. For lighter corrosion, you can use pumice paste as well.
If the corrosion is heavier, you’ll need to use wire brushing or grinding with dry abrasive blasting. When done check with a 10x magnifying glass if any corrosion is still remaining. Then clean the surface with fresh water extensively.
Ordering From China
Before you order magnesium die casting parts from China, thoroughly consider all the advantages and disadvantages you’re getting with the metal.
If you’re new to this or thinking of ordering magnesium for the first time, make sure you’re consulting with an expert. Because you need to select the right process and parts for your project. To do so consider your product requirements, application, budget and other factors as well.
If you’re confused feel free to give us a knock in the contact box and I’ll personally get back to you. But then, when you’ve decided to order it, the process is not very different from ordering any other products.
But make sure you’re doing proper research on the quality and choosing the right supplier for your parts.
Contact Sunrise Metal
There is no shortage of options when it comes to choosing the right metal for your products. You need to be careful about choosing the right one that will give you the most value for your money.
Magnesium alloys like any other metals have their own pros and cons. This doesn’t make it bad or good material to use for any equipment. It all depends on what you need for your project and what do you expect out of it.
When you know what you need clearly and have realistic expectations from any product, it becomes easier to decide.