What is the difference between aluminum and zinc alloys when die casting?

28 Nov.,2022

 

Cast Aluminium Gate

Die casting is one of the most cost-effective, accurate, and versatile manufacturing processes in the world today. The process involves injecting molten metal, under pressure, into a reusable die (mold) and once solidified it can be ejected and finished (if necessary) in a variety of ways. The dies are generally constructed of high quality steel and the alloy cast is most commonly aluminum, magnesium, or zinc.

The alloy utilized in your casting will affect the part’s final properties, function, overall price, and life of your die. Aluminum and zinc are the two most popular metals to die cast and each have their own physical and mechanical properties which affect their cast-ability. Magnesium is the third most popular alloy to die cast but A&B does not work with it. Factors such as strength, longevity, melting temperature, and functionality need to be looked at closely before choosing the proper alloy. When choosing an alloy for your die cast parts machining and finishing operations also need to be taken into account.

Aluminum Alloys

Aluminum alloys are the most common alloys used in die casting today. They can be found in most items that we use every single day since are strong, lightweight, and economical for high-volume casting. Aluminum is very rarely used in its pure form because it tends to crack and shrink; therefore it is typically mixed with other materials including copper, magnesium, and silicon to help increase the alloy’s fluidity, elasticity, corrosion resistance, tensile strength, and hardness to provide it with superior mechanical properties. Aluminum alloy die cast parts tend to maintain their strength at high temperatures, possess good thermal and electrical conductivity, and can be cast with intricate geometries and thin walls while maintaining their strength.

Zinc Alloys

Zinc alloys are perfect for smaller and more complex shapes since no other alloys can be cast with such tight tolerances and thin walls. Zinc’s superior strength and hardness is an ideal alternative for machined, pressed, stamped, and fabricated components. Zinc also has excellent thermal and electrical conductivity, requires less tooling or secondary operations, and can be cast at moderate temperatures which provide significant energy and processing savings over other metals and engineering alloys.

How do you determine which alloy to choose for your die cast project?
Die casting offers the ability to create a wide variety of parts produced with precision at high speed. To determine which alloy would be best for your specific project you need to look closely at each alloy’s unique mechanical and physical properties since these will dramatically impact the performance and longevity of your application.

Other factors to take into consideration:
• Raw material cost
• Size of the finished part
• Wall size capability
• Tensile strength and hardness
• Weight requirements for the finished part
• Strength-to-weight ratio
• Dimensional stability and accuracy
• Corrosion resistance
• Thermal conductivity
• Electrical conductivity
• Finish needs and options
• Machining characteristics
• Recyclability

The alloy you select plays a huge role in the overall cost and performance of your die cast components. Since each alloy used in die casting offers its own unique benefits for your final die cast parts there is quite a lot to factor into the design and engineering of a new component.

It is not always easy to select the right alloy for your project. Need a hand? With over 75 years of die casting expertise, our team of experienced engineers will evaluate your requirements to help you decide which would be the best alloy option for your application to achieve the desired result for your part. Our in-depth knowledge and experience allows us to control the entire pre- and post-operative processing, as well as provide turn key part solutions with a variety of options, to meet our customer’s individual needs. Contact A&B Die Casting to get started on your next project today!