Aluminum 6061 vs 6063: Quick Comparison at a Glance
Chemical Composition: Aluminum 6061 vs 6063
Mechanical Properties of Aluminum 6061 and 6063
Thermal and Electrical Conductivity Comparison
While strength and formability are key factors when selecting aluminum, thermal and electrical conductivity can also influence your choice-especially in applications involving heat transfer or electrical grounding.
Thermal Conductivity:
Both GNEE 6061 and 6063 aluminum provide good thermal conductivity, but 6063 generally performs slightly better due to its higher aluminum purity and lower alloying content.
GNEE 6063: ~201–209 W/m·K
GNEE 6061: ~167–170 W/m·K
This makes GNEE 6063 the preferred choice for applications such as LED housings, heat sinks, and architectural fins where effective heat dissipation is important.
Electrical Conductivity:
Similarly, GNEE 6063 has a slight advantage in electrical conductivity, making it better suited for low-voltage connectors, grounding systems, or decorative trim requiring some functional conductivity.
GNEE 6063: ~53–56% IACS
GNEE 6061: ~40–44% IACS
However, neither alloy matches the performance of pure aluminum or specialized conductor-grade alloys (such as 1350), so their use in electrical applications is generally secondary or structural.
Manufacturing Process: Aluminum 6061 vs. 6063
Here's a closer look at how GNEE 6061 and 6063 aluminum perform in various industrial processes.
Casting:
Casting is a fundamental process in aluminum alloy production, especially for creating billets used in extrusion or forging. Comparing GNEE 6061 and 6063 aluminum, 6063 demonstrates clear advantages for large-scale, high-volume casting applications.
GNEE 6063 features a purer composition with fewer alloying elements, resulting in excellent casting flow, reduced susceptibility to defects like porosity or inclusions, and enhanced process stability. It is particularly well-suited for semi-continuous casting of long billets, commonly employed in architectural profiles such as window frames and decorative extrusions.
In contrast, GNEE 6061 contains copper and chromium, which enhance strength but make casting more challenging. Careful control of temperature and cooling rates is required to prevent segregation. This alloy is best used for casting billets intended for high-strength structural components, such as automotive frames or aerospace forgings.
Extrusion
Extrusion is the primary forming method for 6xxx series aluminum, and the differences in flow characteristics between alloys are particularly significant.
GNEE 6063 aluminum provides excellent extrudability due to its high ductility and fine grain structure. With elongation rates up to 25–30%, it is ideal for producing complex, thin-walled, or long aluminum profiles such as decorative trims, hollow window frames, or curtain wall sections. Its processing advantages include:
High extrusion speeds (up to 60–100 m/min)
Reduced die wear
Smooth surface finish requiring minimal post-processing
GNEE 6061 aluminum, although stronger, has lower plasticity. Its extrusion requires higher temperatures (500–520°C versus 480–500°C for 6063) and greater force. Speeds are generally slower (30–60 m/min), and care must be taken to prevent cracking or uneven flow. It is better suited for moderately complex structural profiles, such as support arms, rails, or camper frames.
Rolling
Rolling converts aluminum into sheets or plates, where surface quality and resistance to deformation are key. Choosing between 6061 and 6063 depends on the application.
GNEE 6063 is well-suited for thin-gauge rolling (0.3–3 mm). Its excellent plasticity and low work-hardening rate produce smooth, uniform surfaces (Ra < 0.8 μm), making it ideal for decorative sheet metal or parts requiring further forming, such as appliance casings or architectural cladding.
GNEE 6061 is better for medium to thick plates (3–100 mm) intended for structural use, including machinery bases, marine decks, or heavy-duty frames. Its higher strength necessitates greater rolling force, and intermediate annealing is often required to prevent cracking.
CNC Machining: Precision & Surface Finish
When machining GNEE 6061 and 6063, the choice depends on whether strength or surface quality is the priority.
GNEE 6063, being softer, produces lower cutting resistance and clean, non-clogging chips. This makes it suitable for high-speed precision machining of decorative components, such as ornamental parts or slim shafts. Tool wear is minimal, and high-speed steel tools are usually sufficient.
GNEE 6061, especially in T6 temper, provides superior strength (~290 MPa tensile) and dimensional stability. It requires carbide tooling and higher cutting forces. Chips are brittle and break easily, which aids efficient machining of structural components like brackets, joints, or load-bearing housings.
Sheet Metal Welding
Weldability is a crucial consideration in assembly and fabrication, especially for structural or architectural applications.
GNEE 6063 is highly weldable due to its clean chemistry and absence of copper. It has low susceptibility to hot cracking and performs well with MIG/TIG welding using ER4043 filler wire. Weld seams are strong (up to 80% of base metal), making it ideal for profile splicing in window and door frames.
GNEE 6061, while weldable, is more challenging because its copper content increases the risk of hot cracking. ER5356 filler wire is recommended, and precise control of heat input is essential. Post-weld aging or localized heat treatment is often required to restore mechanical strength, particularly for load-bearing welds in automotive or aerospace structures.
