6061-T6 Aluminum Alloy Sheet & Extrusion Technical Specification
Comprehensive technical specification for 6061-T6 aluminum alloy sheet and extrusion, covering Canadian stock sizing, machinability, tooling, common defects, and storage guidelines for fabrication and machining operations.
Material Overview & Common Uses
6061-T6 is a precipitation-hardened aluminum alloy offering a good balance of strength, corrosion resistance, and machinability. It is widely used in structural components, aerospace fittings, marine hardware, automotive parts, bicycle frames, and general fabrication. In Canadian shops, it is the default choice for jigs, fixtures, and custom extrusions due to its consistent properties and availability in standard sheet and extrusion profiles.
Core Technical Properties & Sizing
| Property | Value |
|---|---|
| Temper | T6 (solution heat-treated and artificially aged) |
| Tensile Strength | 310 MPa (45,000 psi) minimum |
| Yield Strength | 276 MPa (40,000 psi) minimum |
| Elongation | 12% in 50 mm (2 in) |
| Hardness | 95 Brinell (500 kg load, 10 mm ball) |
| Density | 2.70 g/cm³ (0.0975 lb/in³) |
| Modulus of Elasticity | 68.9 GPa (10,000 ksi) |
| Thermal Conductivity | 167 W/m·K (at 25°C) |
| Electrical Resistivity | 4.3e-6 ohm·cm |
Standard Sheet Sizes (Canadian Stock)
| Thickness | Sheet Dimensions |
|---|---|
| 0.032″ (0.81 mm) | 48″ × 96″, 48″ × 120″, 60″ × 120″ |
| 0.040″ (1.02 mm) | 48″ × 96″, 48″ × 120″, 60″ × 120″ |
| 0.050″ (1.27 mm) | 48″ × 96″, 48″ × 120″, 60″ × 120″ |
| 0.063″ (1.60 mm) | 48″ × 96″, 48″ × 120″, 60″ × 120″ |
| 0.080″ (2.03 mm) | 48″ × 96″, 48″ × 120″, 60″ × 120″ |
| 0.090″ (2.29 mm) | 48″ × 96″, 48″ × 120″, 60″ × 120″ |
| 0.100″ (2.54 mm) | 48″ × 96″, 48″ × 120″, 60″ × 120″ |
| 0.125″ (3.18 mm) | 48″ × 96″, 48″ × 120″, 60″ × 120″ |
| 0.160″ (4.06 mm) | 48″ × 96″, 48″ × 120″ |
| 0.190″ (4.83 mm) | 48″ × 96″, 48″ × 120″ |
| 0.250″ (6.35 mm) | 48″ × 96″, 48″ × 120″ |
Standard Extrusion Profiles
Angles (equal and unequal legs), channels, tees, I-beams, rectangular and square tubes, round tubes, and custom shapes per ASTM B221. Common profiles:
- 1″ × 1″ × 1/8″ angle
- 2″ × 2″ × 1/4″ angle
- 1″ × 2″ × 1/8″ channel
- 1″ square tube 0.125″ wall
- 2″ round tube 0.125″ wall
Tolerances (Sheet – ASTM B209)
| Parameter | Tolerance |
|---|---|
| Thickness (up to 0.125″) | ±0.005″ |
| Thickness (0.126″–0.250″) | ±0.007″ |
| Width (up to 48″) | ±1/8″ |
| Width (48″–60″) | ±3/16″ |
| Length (up to 120″) | ±1/4″ |
| Flatness (0.063″ and above) | 1/4″ in any 48″ length |
Tolerances (Extrusion – ASTM B221)
| Parameter | Tolerance |
|---|---|
| Cross-section (dimensions up to 1″) | ±0.010″ |
| Cross-section (1″–2″) | ±0.015″ |
| Cross-section (2″–4″) | ±0.020″ |
| Twist | 1° per foot maximum |
| Straightness | 0.0125″ per foot maximum |
Machinability, Tooling & Feeds
6061-T6 has excellent machinability (rating: 8/10). It produces small, easily broken chips. Recommended tooling: carbide inserts (C2 grade) for high-speed machining, high-speed steel (HSS) for lower volume. For milling: use 2- or 3-flute end mills with polished flutes to reduce built-up edge. Avoid using coolant with high chlorine content to prevent stress corrosion cracking. Use mist or flood coolant with 5–10% soluble oil.
| Operation | Tooling | Speed (SFM) | Feed | Notes |
|---|---|---|---|---|
| Milling – Roughing | Carbide (C2), 2–3 flute | 800–1200 | 0.005–0.015 in/tooth | Depth up to 0.100″ per pass |
| Milling – Finishing | Carbide (C2), 2–3 flute | 800–1200 | 0.002–0.005 in/tooth | Depth 0.010–0.030″ |
| Milling – HSS | HSS end mill | 200–400 | 0.003–0.010 in/tooth | Reduce speed for HSS |
| Drilling | 118° point angle HSS or carbide | 200–400 | 0.003–0.010 in/rev | Use peck cycle for deep holes |
| Tapping | Spiral point tap | 50–100 | — | Use cutting fluid (water-soluble oil or kerosene) |
| Sawing | Carbide-tipped blade, 10–12 TPI | 3000–5000 | — | Use mist coolant |
| Extrusion (same as milling) | Carbide (C2) | 800–1200 | Reduce feed by 10–15% | Account for grain direction effects |
Common Defects & Quality Control
| Defect | Description | Quality Control / Prevention |
|---|---|---|
| Surface scratches & die lines | From handling or extrusion die wear | Visual inspection under good lighting; use protective interleaving |
| Delamination | Separation of layers in sheet, often due to inclusions or rolling defects | Reject material with visible layer separation; perform bend test |
| Pitting corrosion | From improper storage or exposure to chlorides | Store in dry environment (RH <60%); avoid copper/brass contact |
| Warpage | From uneven cooling or stress relief | Check flatness with straightedge; reject if >1/4″ in 48″ |
| Burrs | From dull tooling or improper feeds | Deburr edges; sharpen tooling; adjust feed parameters |
| Inclusions | Non-metallic particles (e.g., oxides) causing porosity or weak spots | Visual inspection; reject if visible; perform tensile test per ASTM B557 |
| Grain flow lines | Visible on extrusions; affect anodizing uniformity | Check with etch inspection; accept if within customer specification |
Additional QC checks: Check thickness with micrometer (3 points per sheet), hardness test (Rockwell B, target 60–70 HRB), and for extrusions check twist and straightness with surface plate and feeler gauge. Reject material with visible cracks, deep scratches (>0.010″), or thickness out of tolerance.
Storage, Handling & Racking Guidelines
Store 6061-T6 sheet and extrusion in a dry, indoor environment with relative humidity below 60%. Avoid direct contact with concrete floors – use wooden pallets or rubber mats to prevent moisture wicking.
| Material Form | Storage Method | Key Requirements |
|---|---|---|
| Sheet (thin, <0.125″) | Stack flat on level surface, interleave with kraft paper or plastic film | Max stack height 24″; use suction cups or edge protectors for lifting |
| Sheet (thick, ≥0.125″) | Stack flat on level surface | Max stack height 36″; use clean, dry gloves |
| Extrusions | Horizontal racks with supports every 4 ft; padded or rubber-lined cradles | Use cantilever racks, arms spaced 24–36″; slings or padded clamps for lifting |
| Long-term storage (>6 months) | Wrap in VCI (vapor corrosion inhibitor) paper | Label with material grade, thickness, and date received |
| General | Do not store near copper or brass | Implement FIFO (first-in, first-out) rotation |
Racking: Use cantilever racks for extrusions with arms spaced at 24–36 inches. For sheet, use vertical sheet racks with dividers every 6 inches to prevent leaning and bending. Label each rack with material grade, thickness, and date received. Implement FIFO (first-in, first-out) rotation.