The difference between extruded aluminum profiles and die-cast aluminum parts

Many people cannot distinguish between the processes and applications of extruded aluminum profiles and die-cast aluminum. Let's take a look at the differences between these two processing methods. Extruded aluminum profiles are made by an extruder that pushes a heated aluminum billet to its critical point through a die. Die-cast aluminum is made from aluminum ingots and alloy materials, melted in a furnace, and formed in a die-casting machine. The shapes of die-cast aluminum products can be designed to resemble toys, with various forms, making connections in all directions easier. In addition, it has high hardness and strength, and can be mixed with zinc to form a zinc-aluminum alloy.

Advantages of Aluminum Profiles
Less machining: Aluminum alloys can be extruded into any complex parts. Therefore, with reasonable design, extruded aluminum profiles can be easily assembled, reducing the need for machining. Some shapes can only be obtained through extrusion and cannot be achieved by other processes.

Low cost of aluminum extrusion dies: Compared to other competing materials such as rolling, casting, and forging, aluminum extrusion dies are cost-effective.

High structural efficiency: Aluminum extrusions can achieve maximum structural efficiency. Profiles can be used where strength is needed, and aluminum can be removed where it is not required.

Lightweight: Extruded aluminum profiles are lightweight, strong, and durable. Due to the differences in performance between aluminum and other competing materials, aluminum structures of the same effect weigh about half as much as other metal structures, which are also harder to process.

Various surface treatment options: Corrosion-resistant: With powder coating or electrophoretic coating, designers can achieve any desired color. This also includes natural silver or colored anodized coatings.

Low maintenance: Aluminum is a naturally durable metal, and the above surface treatments enhance its durability.

Disadvantages of Extruded Aluminum Profiles
1. Inconsistent structure and performance of products. Due to uneven metal flow during the extrusion process (especially severe in forward extrusion without lubrication), the structure and performance of the extruded product vary between the surface and the core, as well as between the head and the tail.

2. Poor working conditions for extrusion dies and significant die wear. During extrusion, the billet is in a nearly closed state, and the triaxial pressure is high, requiring the die to withstand high pressure. At the same time, the tooling dies in hot extrusion are usually subjected to high temperatures and high friction, greatly affecting their strength and service life.

3. Low production efficiency. Except for the continuous extrusion process developed in recent years, all conventional extrusion methods cannot achieve continuous production. Generally, extrusion speed is much lower than rolling speed, and there is significant geometric waste and low yield in extrusion production.

Applications of Extruded Aluminum Profiles:
Extruded aluminum profiles are mainly used for manufacturing broken bridge aluminum doors and windows, electronic heat sinks, curtain walls, and other products.

What is aluminum die casting?

Die-cast aluminum has low density but relatively high strength, comparable to or exceeding that of high-quality steel. It has good plasticity, can be processed into various profiles, and has excellent electrical conductivity, thermal conductivity, and corrosion resistance. It is widely used in industry, second only to steel. Aluminum alloys can be divided into two main categories based on processing methods: wrought aluminum alloys and casting aluminum alloys. Wrought aluminum alloys can withstand pressure processing and can be made into aluminum alloys of various shapes and specifications.

Advantages of Aluminum Die Castings:
1. Since die-cast aluminum is formed using mold die casting, the aluminum parts have accurate dimensions and smooth surfaces; they can generally be used directly without machining, or require minimal machining. This not only improves metal utilization but also reduces the need for extensive machining equipment and labor.

2. Die-cast aluminum is inexpensive; it can be combined with other metals or non-metal materials, saving assembly time and metal.

3. Die-cast aluminum has high production efficiency. A horizontal cold-chamber die-casting aluminum machine can cast aluminum 600-700 times in an average of 8 hours, while a small hot-chamber die-casting machine can cast aluminum 3,000-7,000 times on average in the same period.

4. Aluminum die-casting molds have a long service life. A pair of aluminum die-casting molds and die-cast zinc-aluminum alloys can last hundreds of thousands, even up to a million cycles; they are easy to mechanize and automate.

5. Die-cast aluminum products are of high quality, with casting dimensional accuracy generally corresponding to grades 6–7, and sometimes up to grade 4; the surface finish is generally grades 5–8; strength and hardness are higher—the strength is typically 25–30% greater than sand-castings, although elongation is reduced by about 70%; dimensions are stable with good interchangeability; thin-walled and complex aluminum castings can also be produced.

Disadvantages of die-cast aluminum:

1. Low hardness and poor wear resistance;

2. Relatively large volume shrinkage during solidification, about 6.6%;

3. High coefficient of linear expansion;

4. Prone to sticking to the mold, requiring strict control of iron content within 0.8%-0.9%;

5. Low melting point, limiting high-temperature usage.

Applications of Die-Cast Aluminum Products:

Currently, the aluminum alloy die-casting process has been widely used in various fields. Aluminum alloy die-cast products are mainly used in automotive parts, electronic casings, communications, motors, aviation, ships, household appliances, furniture parts, digital device casings, handicrafts, security product casings, LED lighting (lampshades), and some new energy industries. High-performance, high-precision, and high-toughness premium aluminum alloy die-cast products are also used in industries with relatively high requirements, such as large aircraft and ships. Their main use remains in parts or casings of certain instruments, as the aluminum alloy forming process has become a widely used technique.