What is the composition of Aluminum 6061?

Typical composition by weight: Al balance (95.8–98.6%), Mg 0.8–1.2%, Si 0.4–0.8%, Cu 0.15–0.40%, Cr 0.04–0.35%, Zn ≤0.25%, Fe ≤0.7%, Mn ≤0.15%, Ti ≤0.15%, others ≤0.15%.

What is the difference between 6061-T6 and 6061-T4?

T6 is solution heat treated and artificially aged (higher strength). T4 is solution heat treated and naturally aged (lower strength, better formability). T651/T451 variants include stress relieving by stretching.

Is Aluminum 6061 weldable?

Yes. 6061 is generally weldable by common processes. Gas welding may require special technique; arc/resistance/spot/seam welding are typically rated as good.

How corrosion resistant is 6061?

General corrosion resistance is good (often usable in industrial atmospheres without protection). Stress-corrosion cracking resistance is excellent in T6 and good in T4.

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Aluminum 6061 – Material Properties

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Composition (wt%)
Temper designations (T6, T651, T4, T451)
Characteristics (corrosion, weldability, workability)
6061 product property pages
Related aluminum properties
Reference

Aluminum 6061 is one of the most versatile heat-treatable aluminum alloys in the 6000 series, combining good formability, corrosion resistance, and medium strength. It is widely used for heavy-duty structures, railroad cars, and pipelines. The alloying elements are primarily magnesium and silicon, with small additions of copper and chromium.

Aluminum 6061 Composition (wt%)

Aluminum 6061 – Composition by Weight (Typical Ranges)
Element	Wt. %	Element	Wt. %
Aluminum	95.8 – 98.6	Iron	≤ 0.70
Silicon	0.40 – 0.80	Copper	0.15 – 0.40
Manganese	≤ 0.15	Chromium	0.04 – 0.35
Magnesium	0.80 – 1.20	Zinc	≤ 0.25
Titanium	≤ 0.15	Others	≤ 0.15

Temper Designations (6061)

Common 6061 temper designations:

T6 – Solution heat treated and artificially aged.
T651 – Solution heat treated, stress relieved by stretching, then artificially aged.
T4 – Solution heat treated and naturally aged.
T451 – Solution heat treated, stress relieved by stretching, naturally aged.

Aluminum 6061 – Characteristics by Temper

Ratings: Letters are qualitative (context: A = best across the set)
Characteristic	6061-T6 / T651 / T6510	6061-T4 / T451 / T4510
General resistance to corrosion	Rated B (usable in many industrial atmospheres without protection)
Stress-corrosion cracking	Rated A (no known failure in service or lab tests)	Rated B (no known failure in service; limited failures for short transverse in lab)
Workability (cold)	Rated C (scale A–D)	Rated B (scale A–D)
Machineability	Rated C (scale A–E)
Gas welding	Rated B (weldable with appropriate technique)
Brazeability / Arc / Resistance spot & seam welding	Rated A (generally weldable by commercial processes)

Aluminum 6061 Mechanical Properties

Material Properties of Aluminum

Note: Ratings are comparative within the 6061 temper set and for general guidance only. Actual performance depends on product form, processing, and service conditions.

Reference

MMPDS-01, Metallic Materials Properties Development and Standardization (2003).
AA-FMA-17, The Aluminum Association, Forming and Machining Aluminum (1988).
AA-38, The Aluminum Association, Structural Design with Aluminum (1987).