The 6xxx or 6000 series of wrought aluminum alloys features Magnesium (Mg) and Silicone (Si). These alloying element forms Magnesium Silicide (Mg₂Si) with aluminum. The two predominant components must maintain perfect proportions to create the Al-Mg-Si system.

Aluminum 6xxx Alloy Characteristics

The Mg-Si combo imparts and enhances some important mechanical properties for grade 6xxx alloys. Some key characteristics of 6000 series alloys are –

• Medium to high mechanical strength
• Good resistance to corrosion and rust
• Sufficient weight-to-strength ratio
• Ultimate tensile strength of 18ksi to 58ksi
• Heat treatable for further strengthening
• Good formability, especially for extrusions
• Sensitivity to naturally solidification crack
• Hard to weld due to susceptibility to cracking
• Susceptible to high-temp artificial aging
• Good for anodizing, coloring, and coating
• Has excellent machinability

Solution treatment followed by aging can enhance the yield strength by 3-5 times. Artificial age hardening or precipitation hardening requires a temperature of 160-182°C (320-360°F). 6000 series alloys can be readily welded using 4xxx or 5xxx fillers.

Common Aluminum Grade 6xxx Alloys

Grade 6000 aluminum alloys contain only a fraction of Mg and Si. The maximum alloying percentages are about 1.5% and 1.8% for Mg and Si, respectively. Slight differences produced newer alloys, boosting the total alloy number of this series.

The most widely used alloys of the aluminum 6000 group are –

Grade 6053 (1.1% – 1.4% Mg, 0.15% – 0.35% Cr)

Grade 6061 (0.8% – 1.2% Mg, 0.4% – 0.8% Si)

Grade 6063 (0.45% – 0.9% Mg, 0.2% – 0.6% Si)

Grade 6066 (0.8% – 1.4% Mg, 0.9% – 1.8% Si)

Grade 6070 (0.50% – 1.2% Mg, 1.0% – 1.7% Si)

Grade 6082 (0.6% – 1.2% Mg, 0.7% – 1.3% Si)

Grade 6101 (0.35% – 0.8% Mg, 0.3% – 0.7% Si)

Grade 6151 (0.45% – 0.8% Mg, 0.6% – 1.2% Si)

Grade 6201 (0.6% – 0.9% Mg, 0.5% – 0.9% Si)

Grade 6463 (0.4% – 0.9% Mg, 0.2% – 0.6% Si)

Excessive silicone in the composition can cause slower precipitation, leading to poor ductility. As impurities, Manganese (Mn) and Chromium (Cr) can effectively reduce the adverse effects.

That’s why Cr and Mn are also present with Copper (Cu) in almost all alloys in a meager portion. Additional minor impurities include Boron (B), Zinc (Zn), Lead (Pb), Titanium (Ti), and Iron (Fe).

Applications for Aluminum 6xxx Series Alloys

Easy machinability and reasonable mechanical properties make grade 6xxx alloys suitable for many uses. These alloys exist in standard forms like sheets, plates, extrusions, flat bars, and tubes. Additional forms like beam, billet, coil, pipe, rod, square, box, strip, and wire are available.

Grade 6061 and 6063 alloys are widely used for CNC machining intricate parts for various industries.

Fabrication

The heat-treatable alloys have widespread adaption in the welding fabrication process. However, its arc welding must require a filler material to avoid solidification cracks. Diluted 6xxx alloys with 4xxx or 5xxx alloys as fillers can provide a satisfying outcome.

Transportation

The excellent corrosion resistance of the alloy gives automotive parts further durability. Adding moderate strength is good enough for many transportation parts. Some non-flight aircraft parts have applications for common alloys like 6061.

Construction

Sufficient strength, great finish, and protective coating/polish enable these alloys for structural uses. Lower-strength alloys like 6063 are in frames where strength isn’t the primary consideration. Windows, doors, railings, and electrical tools have them.

Architectural

Shiny metal finish requires almost no maintenance against everyday rigors. Good mechanical properties make these 6000 alloys perfect for decorative purposes. Structure, furniture, reel, firearm suppressor, etc., also feature some of these common alloys.

Which Aluminum Alloys is Best for Your Project?

Aluminum grade 6xxx alloys have various types of applications in the industry. We also provide CNC machining services for popular Grade 6xxx alloys such as Al6061 and Al6063. We have the latest technology equipment to ensure high precision and speed for your parts. If you have any queries about aluminum alloys, feel free to contact us.