Henan Gnee New Material Co., Ltd. is one of the most reliable manufacturers and suppliers of 6061 Seamless Aluminum Tube And Pipe in China. With abundant experience, we warmly welcome you to wholesale high quality 6061 Seamless Aluminum Tube And Pipe in stock here from our factory. Good service and reasonable price are available.
What is 6061 Seamless Aluminum Tube
6061 is a 6000-series aluminum alloy in the Al-Mg-Si (magnesium-silicon) family. It is a precipitation-hardenable alloy: its strength comes from a heat treatment that forms fine Mg2Si particles inside the metal. The "seamless" form is produced by extrusion of a hollow billet, so the tube has no longitudinal weld seam. This gives uniform wall properties around the full circumference and removes the weld as a potential leak or fatigue path.
Engineers select 6061 tube because it balances three needs at once: enough strength for load-bearing frames, good weldability for fabricated assemblies, and sufficient corrosion resistance for outdoor and marine service. It is not the strongest aluminum alloy (7075 is stronger) and it is not the most corrosion-resistant (5083 / 5052 lead there), but it is the most versatile structural grade for general supply.
Chemical Composition
Composition below follows ASTM B221 / B241 and the AA 6061 registration. Values are weight percent.
| Element | Min % | Max % | Role / Function |
|---|---|---|---|
| Silicon (Si) | 0.40 | 0.80 | With Mg forms Mg2Si; primary strengthening precipitate after heat treatment. Improves castability and machinability. |
| Iron (Fe) | - | 0.70 | Impurity control; excess reduces ductility and surface finish. Kept low for extrusion quality. |
| Copper (Cu) | 0.15 | 0.40 | Raises strength and hardness; slightly reduces corrosion resistance and weldability. |
| Manganese (Mn) | - | 0.15 | Refines grain structure and limits recrystallization; minor strength contribution. |
| Magnesium (Mg) | 0.80 | 1.20 | Forms Mg2Si with Si; main source of strength and a positive factor for corrosion resistance. |
| Chromium (Cr) | 0.04 | 0.35 | Controls grain growth and improves stress-corrosion resistance. |
| Zinc (Zn) | - | 0.25 | Kept low to avoid lowering corrosion resistance. |
| Titanium (Ti) | - | 0.15 | Grain refiner; improves toughness and surface quality. |
| Aluminum (Al) | Remainder | Remainder | Base metal; balance to 100%. |
Mechanical Properties
| Temper | UTS (MPa) | Yield (MPa) | Elongation (%) | Hardness |
|---|---|---|---|---|
| T6 | 310 (45 ksi) | 276 (40 ksi) | 12 | 95 HB |
| T6511 | 310 (45 ksi) | 276 (40 ksi) | 12 | 95 HB |
| T4 | 241 (35 ksi) | 145 (21 ksi) | 22 | 65 HB |
| O (annealed) | 124 (18 ksi) | 55 (8 ksi) | 25 | 30 HB |
Physical & Thermal Properties
| Property | Value (metric) | Value (imperial) |
|---|---|---|
| Density | 2.70 g/cm³ | 0.0975 lb/in³ |
| Melting range | 582–652 °C | 1080–1206 °F |
| Modulus of elasticity | 68.9 GPa | 10.0 ×10&sup6; psi |
| Electrical conductivity | 43% IACS | ~25 MS/m |
| Thermal conductivity | 167 W/(m·K) | 115 BTU·in/(ft²·h·°F) |
| Coefficient of thermal expansion (CTE) | 23.6 µm/(m·°C) | 13.1 µin/(in·°F) |
6061 Seamless Aluminum Tube Specifications Table
Standard supply ranges for seamless and extruded 6061 tube. Non-standard sizes are produced to drawing.
| Parameter | Range (metric) | Range (imperial) |
|---|---|---|
| Outer diameter (OD) | 6–300 mm | 0.25–12 in |
| Wall thickness (WT) | 0.5–25 mm | 0.02–1.0 in |
| Length | 1–12 m | 3–40 ft |
| Shapes | Round, square, rectangular, custom profiles | |
| Tempers | T6, T6511, T4, O | |
| Standards | ASTM B241 (seamless), ASTM B210 (drawn), ASTM B221 (extruded), EN 755, AMS 4082 | |
| Tolerance | Per ASTM B241 / EN 755; precision grade on request | |
Heat Treatment & Temper Guide
6061 is heat-treatable. The T6 condition is produced by solution heat treatment followed by artificial aging:
Solution treatment: 530 ± 5 °C, hold then rapid quench (water).
Aging: 175 ± 5 °C for 8 hours (typical), air cool.
T6511: adds 1–3% cold stretch after solution treatment to relieve residual stress before aging - preferred for extrusions and tubes that must stay straight and stable in machined parts.
Welding locally softens the heat-affected zone (HAZ) back toward the T4 condition; full T6 strength is not recovered without re-heat-treatment of the whole part. Design for this when welding carries load.
6061 is mildly quench-sensitive: cooling that is too slow during the water quench lets some Mg2Si form coarsely before aging, which lowers the final strength. Controlled extrusion and prompt quenching keep properties consistent across wall thicknesses. For thick-wall tube, confirm the actual temper and consider T6511 (stress-relieved) to reduce distortion after machining.
Equivalent Designations
| AA | UNS | EN | DIN | JIS | GB | ISO |
|---|---|---|---|---|---|---|
| 6061 | A96061 | EN AW-6061 (AlMg1SiCu) | 3.3211 (AlMg1SiCu) | A6061 | 6061 | AlSi1MgCu |
Corrosion Resistance
Atmospheric: Good in rural, urban, and most industrial atmospheres. A thin oxide film forms spontaneously and limits further attack.
Marine / seawater: Good with a protective finish. Bare 6061 performs well in splash zones but benefits from anodizing or coating in continuous immersion.
Galvanic: Moderate. Avoid direct contact with steel or copper without insulation; use dielectric washers or coatings to break the electrical path.
Stress-corrosion cracking (SCC): Resistant in normal service. Risk rises only under high sustained tensile stress plus specific corrosive environments - less sensitive than 7xxx high-strength alloys.
After finishing: Anodizing and powder coating extend service life and seal the surface against pitting.
Fabrication
Welding. 6061 is among the most weldable high-strength aluminum alloys. Use filler metal ER4043 for general work, or ER5356 when higher joint strength or closer anodizing color match to the base metal is required. Note that 5xxx fillers raise joint strength; 4xxx fillers give a lighter anodized tone. Pre-clean and use adequate heat sink to limit HAZ softening.
Machining. Good machinability in T6. Use sharp carbide tooling, generous rake angle, and flood coolant to avoid built-up edge. T6 machines more cleanly than O or T4.
Formability. Moderate. T4 and O tempers bend more readily than T6; for tight bends on T6, consider local annealing or select T4. As a rule, the minimum bend radius for T6 tube is roughly 2–3 times the wall thickness with a proper mandrel or wipe-die setup, while O tempers bend at smaller radii without cracking. Tube can be cut, drilled, tapped, and CNC-machined to tolerance, and ends can be chamfered, threaded, or fitted with couplings for assembly.
Surface Finishes
| Finish | Description | Typical use |
|---|---|---|
| Mill finish | As-extruded, uncoated surface | Structural, internal, painted-over parts |
| Anodized (Type II / III) | Oxide layer 5–25 µm; better wear and corrosion resistance | Architectural, decorative, marine |
| Powder coated | Polymer layer, multiple colors | Architectural, equipment housings |
| PVDF / fluoropolymer | High weather resistance, long color retention | Exterior cladding, coastal structures |
| Polished / brushed | Mechanical surface texture | Decorative, display |
Applications
Structural frames & frameworks: Machine guards, workstations, 80/20-style framing - 6061 tube gives high stiffness at low weight and welds cleanly.
Marine & offshore: Handrails, ladders, supports - corrosion resistance with anodized or coated finish.
Automotive & transport: Chassis bracing, trailer frames, roll cages - strength-to-weight and weldability.
Bicycle & sporting goods: Frames, handlebars - light, stiff, easy to TIG weld.
Hydraulic & compressed-air lines: Seamless tube removes the weld seam as a leak path.
Rail & mass transit: Interior structures, seat frames - fire-smoke-toxicity-friendly, light.
Industrial machinery: Cylinder bodies, guides, jigs - machinable T6 with stable dimensions (use T6511).
Robotics & automation: Lightweight arms and gantries keep moving inertia low for faster cycle times; stiffness per mass is the reason.
6061 vs Other Aluminum Alloy Comparison
| Property | 6061-T6 | 6063-T6 | 6082-T6 | 5052 (H32) | 7075-T6 |
|---|---|---|---|---|---|
| Series | Al-Mg-Si | Al-Mg-Si | Al-Mg-Si | Al-Mg | Al-Zn-Mg-Cu |
| UTS (MPa) | 310 | 241 | 290–310 | [To be confirmed] | 570 |
| Weldability | Excellent | Excellent | Good | Good | Poor |
| Corrosion resistance | Good | Good | Good | Very good | Moderate |
| Heat-treatable | Yes | Yes | Yes | No | Yes |
| Suited for | General structure | Architecture | EN structural | Marine plate | Aerospace |
7075 UTS shown from reference data; confirm per MTC for your stock. 5052 values are [To be confirmed] in our dataset and provided per MTC.
Why Choose GNEE
Established supply, wide reach: GNEE has supplied aluminum products since 2008 and ships to more than 100 countries, with export experience across structural, marine, and industrial sectors.
Flexible order size: Minimum order quantity is flexible - small trial orders are negotiable, so you can qualify the material before a large run.
Custom sizes and tempers: We cut to length and supply T6 / T6511 / T4 / O and custom OD × WT to drawing. Non-standard profiles are produced against your specification.
Documented quality: Material test certificates (MTC) are available on request, and inspections cover dimensions, surface, and mechanical checks before shipment.
Protected packaging and lead time: Lead time is 15–30 days after drawing or sample confirmation. Tubes are end-capped to prevent denting, wrapped with VCI (volatile corrosion inhibitor) paper, bundled, and packed in seaworthy wooden crates or on heat-treated pallets so they survive long ocean transit without surface staining.
Clear trade terms: Shipment is available on FOB, CIF, or EXW terms, with common departure ports including Qingdao, Shanghai, and Tianjin. Incoterms are confirmed per order so freight and risk transfer match your import setup.
Drawing review and technical support: Send your drawing or spec sheet and we check temper, tolerance, and standard before production, so the tube you receive matches the assembly it feeds rather than a generic catalogue size.
Taken together, these points mean you get a documented, made-to-order 6061 tube rather than an unexplained commodity length - useful when the part enters a qualified BOM or a regulated end market.
Contact GNEE for specification and pricing
FAQ
Q1: Can 6061 seamless tube be welded?
A: Yes. 6061 is one of the most weldable high-strength aluminum alloys. Use ER4043 for general joints or ER5356 for higher strength; the HAZ softens toward T4 after welding.
Q2: Which temper should I choose for structural use?
A: T6 (or T6511 for stress-relieved, more stable extrusions) is the standard choice when you need high strength and stiffness. Choose T4 or O if you must bend the tube sharply before assembly.
Q3: Is seamless better than welded tube?
A: For pressure, hydraulic, or fatigue-critical service, seamless removes the longitudinal weld as a failure path. For static frames, welded (drawn) tube is often cost-effective.
Q4: What standards apply to your 6061 tube?
A: Supply follows ASTM B241 (seamless), ASTM B210 (drawn), and ASTM B221 (extruded), with EN 755 and AMS 4082 available on request.
Q5: Do you provide test certificates?
A: Yes. Material test certificates (MTC) are available on request, covering chemistry and mechanical properties per the ordered temper.
Q6: What is the minimum order and lead time?
A: Minimum order quantity is flexible and small trial orders are negotiable. Standard lead time is 15–30 days from drawing or sample confirmation; exact timing depends on size, temper, finish, and current mill schedule, and is confirmed when we quote.
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