Cast aluminum performs well in complex shapes and high-volume production with lower costs and minimal machining requirements. Forged aluminum, on the other hand, offers higher strength, better fatigue resistance, and superior structural integrity due to its fine-grain structure. Cast aluminum is well suited for lightweight, complex parts. Forged aluminum is better suited for high-stress, safety-critical components.
This article will take a closer look at the differences between cast and forged aluminum in terms of manufacturing processes, mechanical properties, cost efficiency, industry applications, and selection factors. Read on to learn more about the key differences between them.
Manufacturing Processes
Cast Aluminum
Cast aluminum is the process of pouring molten metal into a mold and letting it cool and solidify.
Common processes include high-pressure die casting, sand casting, and investment casting.
Different processes vary in detail, surface treatment, and production scale.
Aluminum die casting is the most efficient method for high-volume production, with the advantages of high dimensional accuracy and rapid prototyping.
Sand casting and investment casting are more suitable for small batches or products with special requirements for surface quality.
Forged Aluminum
Forged aluminum is formed by applying high pressure to a solid aluminum billet, usually accompanied by a heat treatment.
The main methods include free forging, die forging, and cold forging.
Forging can form a continuous grain flow structure, making the aluminum part dense and defect-free.
However, the final size often needs to be achieved through machining, so the forging process is more time-consuming and material-intensive.
Comparison of Mechanical and Structural Properties
Strength and Durability
Forged aluminum has higher tensile strength and yield strength due to grain refinement and orientation deformation, and is suitable for load-bearing structures.
Cast aluminum has moderate strength and is suitable for non-critical parts.
Fatigue and Impact Resistance
The dense structure and continuous grain flow formed by forging make forged aluminum extremely resistant to fatigue and impact.
Cast aluminum has poor performance under cyclic load environments due to the high internal pores and inclusions.
Weight and Density
Both processes produce lighter aluminum parts, but forged aluminum has a higher strength-to-weight ratio, allowing thinner parts without affecting its strength.
Shape Complexity
Casting supports cast aluminum with complex geometries, including internal cavities, undercuts, and thin-walled structures.
Forging is more suitable for aluminum parts with symmetrical, simple shapes due to tooling limitations.
Post-Processing
Cast aluminum, such as die casting and investment casting, produces parts with smooth surfaces and requires less post-processing.
Forged aluminum usually requires further machining due to its rough surface.
Internal Density
Forged aluminum has extremely low porosity and high consistency. Cast aluminum is prone to defects such as shrinkage cavities and air inclusions if not properly controlled.
|
Attribute |
Cast Aluminum | Forged Aluminum |
|
Strength |
Moderate to low; susceptible to porosity | High; grain refinement greatly improves strength |
|
Fatigue Resistance |
Low; internal voids weaken durability | Excellent; aligned grain handles stress cycles well |
|
Shape Complexity |
High; supports intricate and thin-walled designs | Low; best for simple, symmetric shapes |
| Weight | Lightweight |
Lightweight with better strength-to-weight ratio |
| Surface Finish | Smooth as-cast surface |
Requires machining and surface processing |
| Grain Structure | Random and fragmented |
Continuous and aligned |
| Internal Defects | Higher likelihood of porosity, cracks, and inclusions |
Very low; dense and defect-free structure |
Cost and Production Efficiency
Mold Investment
Cast aluminum mold investment is low, especially for sand casting and gravity casting, suitable for prototype trial production and mass production.
Forged aluminum requires a high-cost mold investment and is suitable for parts with a long life cycle.
Unit Cost
Cast aluminum has a low unit cost because the mold has a long life and fast molding, which is suitable for diluting fixed costs.
Forged aluminum has a high unit cost, and the volume effect is limited due to large mold wear and high processing costs.
Material Utilization Rate
Casting is formed according to the mold, which is close to the finished product size, and almost no extra blanks are needed, so there is less material waste.
Forging requires reserved processing allowances and trimming, and excess metal needs to be removed after forming, which results in high losses.
Production Efficiency
Casting aluminum is highly efficient because it is fast in forming and cooling, and is suitable for automated continuous production.
Forged aluminum requires heating, forming, cooling, and post-processing, so the production cycle is longer.
Industry Application
Automobile
Cast aluminum is often used for non-structural parts with complex shapes such as engine blocks, gearbox housings, and lamp holders.
Forged aluminum is used for important structural parts such as suspension control arms, steering knuckles, and wheels that bear dynamic loads.
Aerospace
Forged aluminum is widely used in load-bearing and flight-critical components such as actuator housings, landing gear assemblies, and wing connectors.
Cast aluminum is usually used for non-critical components such as brackets and housings.
Consumer Products
Cast aluminum is often used in products with high appearance requirements, such as furniture parts and decorative parts.
Forged aluminum is used in products that focus on strength and durability, such as high-end sports equipment and outdoor tools.
Electronics
Cast aluminum is widely used in LED lamp housings, electronic equipment housings, etc., because it can achieve fine structures and smooth surfaces.
Forged aluminum is less commonly used in electronic products.
Industrial Machinery
Forged aluminum is used for structural parts such as shafts, gears, and pressure-bearing joints.
Cast aluminum is suitable for housing parts with inner cavity structures such as housings, pump bodies, and fluid components.
Key Selection Factors
Performance Requirements
Forged aluminum is recommended if the parts need to withstand high loads or cyclic stresses. Cast aluminum is more economical for appearance parts or secondary structural parts.
Design Complexity
Cast aluminum is recommended for complex structures, which can achieve thin walls, inner cavities, and irregular structures.
Forged aluminum is limited by molds and pressure uniformity and is not suitable for manufacturing parts with complex details.
Production and Budget
Cast aluminum is suitable for large-scale production and can significantly reduce unit costs.
Although forged aluminum has a high initial investment, it is more suitable for applications with extremely high reliability requirements.
Post-Processing Requirements
Cast aluminum is close to the shape of the finished product and requires less subsequent processing.
Forged aluminum requires a lot of subsequent machining and heat treatment to meet part specifications.
Usage Environment and Safety Requirements
Forged aluminum is suitable for extreme environments with high pressure, high vibration, and large temperature fluctuations.
Cast aluminum is suitable for use under static or general conditions.
CEX Casting: Squeeze Casting Technology that Achieves Strength Comparable to Forging
Why Can Squeeze Casting Achieve “Forging-Grade” Strength
CEX Casting uses a self-developed squeeze casting process, also known as liquid die forging.
In this process, after the aluminum liquid is slowly injected into the mold, continuous pressure is immediately applied through the upper mechanical device to solidify the metal under pressure.
This method can effectively discharge gas and eliminate pores, while making the metal structure denser and the grains finer, thereby greatly improving the mechanical strength.
The mechanical properties of the final product are comparable to those of 5-series or 6-series forged aluminum alloys.
CEX’s Process Advantages to Ensure “Forging-Grade” Performance
Centralized Smelting System
All aluminum alloy raw materials are uniformly processed in our smelting center, which can effectively remove impurities and gases in the raw materials.
Laminar Feeding System
By optimizing the gate design and runner structure, the aluminum liquid fills the mold in a stable and laminar state, effectively avoiding pores and oxide inclusions caused by metal tumbling.
Advanced Cooling System
Directional cooling channels are integrated inside the mold to solidify the metal layer by layer from the inside out, effectively controlling the grain growth and significantly refining the microstructure.
High-Precision Mold Design
In-house mold design and manufacturing capabilities, the mold is tailored for each part.
Support mold flow analysis to predict potential casting defects before actual production and optimize the mold design in a targeted manner.
Conclusion
Casting aluminum is suitable for large-scale production with complex shapes and cost sensitivity, with the advantages of flexible design and high forming efficiency.
Forging performs better in strength, fatigue life, and structural integrity, and is suitable for high-load and critical application scenarios.
As a precision aluminum alloy casting manufacturer, CEX Casting provides squeeze casting solutions comparable to forging strength, taking into account performance, efficiency, and structural complexity.
Contact us now to get a one-stop aluminum alloy casting solution for your next project.