Selection summary
Overview
6061 is a heat-treatable aluminum-magnesium-silicon alloy used across structural, transportation, marine, and machined components. T6, T651, T6511, annealed, and as-fabricated weld zones have different properties and dimensional behavior.
This page separates standard-oriented limits from typical reference data. Purchase acceptance comes from the ordered specification and certified material test report.
Names and systems
Identity & standards
Similar designations across ASTM, EN, JIS, and other systems are not automatically interchangeable. Product form and ordered standard control chemistry, properties, dimensions, condition, and testing.
Reference chemistry
Composition
| Element | Reference range | Why it matters |
|---|---|---|
| Magnesium | 0.8–1.2% | Mg-Si precipitation strengthening |
| Silicon | 0.40–0.80% | Mg-Si precipitation strengthening |
| Copper | 0.15–0.40% | Strength response |
Concise grade-family reference only. Confirm every element limit against the current standard for the exact product ordered.
Condition matters
Reference properties
Typical 6061-T6/T651 reference; product and thickness control acceptance
Typical 6061-T6/T651 reference; use certified product data
Typical room-temperature reference value
Environment first
Corrosion behavior
Good general atmospheric corrosion resistance with suitable design and finish.
Galvanic couples, marine immersion, crevices, and aggressive alkaline or acidic exposure need review.
Temperature, concentration, deposits, crevices, stress, surface finish, cleaning, and fabrication quality can change service performance.
Service limits
Temperature & service
Elevated temperature and welding can reduce precipitation-hardened strength.
Delivery condition
Heat treatment & condition
6061 is solution-heat-treatable and precipitation hardenable. T4, T6, T651, T6510, and T6511 identify different aging, stress-relief, and product routes.
Fusion welding locally overages or dissolves strengthening precipitates and reduces heat-affected-zone strength; recovery by postweld heat treatment is geometry- and distortion-dependent.
Process route
Fabrication
Machinable, formable in suitable tempers, and readily welded with qualified procedures.
Fusion welding reduces heat-treatable strength around the weld unless postweld treatment is feasible.
Magnetic response: Non-ferromagnetic.
Decision boundaries
Comparisons & substitution
Choose 5052 when sheet formability and non-heat-treatable corrosion performance matter more than 6061-T6 strength.
Choose 6063 when extrusion complexity, visible surface, and anodizing quality dominate; choose 6061 when higher structural strength and broader plate/bar availability dominate.
Where it is used
Applications
Ordering scope
Product forms & standards
Sheet and plate under ASTM B209/B209M, with exact temper and stress-relieved suffix stated.
Extruded bar, rod, profiles, and tube under ASTM B221/B221M or the ordered extrusion standard; drawn tube and forgings use separate standards.
State T6/T651/T6510/T6511 accurately with dimensions, grain direction, residual-stress, straightness, machining, welding, anodizing, and inspection requirements.
Decision support
Selection guidance
Choose this grade when
- A broadly available heat-treatable alloy with useful strength and fabrication flexibility is needed.
- The specified product and temper match machining, welding, and dimensional-stability needs.
Review another grade when
- Better sheet forming favors 5052 or a softer alloy/temper.
- Higher marine plate performance, extrusion finish, or aerospace strength points elsewhere.
Before ordering
Procurement checklist
State alloy, temper, product specification, dimensions, tolerances, surface finish, edge, and quantity.
Require heat or lot traceability and a certificate showing chemistry, temper, mechanical tests, and ordered inspection.
Confirm fabrication, welding, anodizing or coating, flatness, residual-stress condition, packaging, destination, and delivery target.
Differentiate T6, T651, T6510, and T6511 and state residual-stress, straightness, and machining requirements.
Traceable evidence