Aluminum Alloys and Tempers

Nine common aluminum alloys with temper, strength, density, weldability and typical uses.

Aluminum is sold as alloys identified by a four-digit number and a temper. The first digit gives the main alloying element: 1xxx is nearly pure aluminum, 2xxx has copper, 3xxx manganese, 5xxx magnesium, 6xxx magnesium and silicon, and 7xxx zinc. The temper (H for work hardened, T for heat treated) says how the metal was strengthened.

This table compares nine alloys you will meet in everyday work: their strength in the usual temper, density, how well they weld, and what they are used for.

The table

9 rows

Alloy	Series	Main alloying elements	Typical temper	Yield strength (MPa)	Tensile strength (MPa)	Yield strength (ksi)	Tensile strength (ksi)	Density (kg/m3)	Fusion weldability	Typical use
1100	1xxx	Pure aluminum (99.0 percent)	H14	105	110	15.2	16	2710	Excellent	Chemical equipment, foil, heat exchanger fins
3003	3xxx	Manganese	H14	145	150	21	21.8	2730	Excellent	Cookware, tanks, general sheet work
5052	5xxx	Magnesium 2.5 percent	H32	193	228	28	33.1	2680	Excellent	Sheet metal, marine and fuel tanks
5083	5xxx	Magnesium 4.5 percent, manganese	H116	228	317	33.1	46	2660	Excellent	Ships, pressure vessels, welded structures
6061	6xxx	Magnesium and silicon	T6	276	310	40	45	2700	Good	Structural parts, machined parts, frames
6063	6xxx	Magnesium and silicon	T6	214	241	31	35	2700	Good	Extrusions: architectural and tubing
6082	6xxx	Magnesium, silicon, manganese	T6	260	310	37.7	45	2710	Good	Structural parts (the common European alloy)
2024	2xxx	Copper and magnesium	T3	345	483	50	70.1	2780	Poor (not fusion welded)	Aircraft structure, high-strength parts
7075	7xxx	Zinc, magnesium, copper	T6	503	572	73	83	2810	Poor (not fusion welded)	Highest-strength machined parts, aircraft, molds

Source and notes: Typical room-temperature values for the named temper (ASM Handbook, Aluminum Association "Aluminum Standards and Data"; minimums in the standards are lower). Temper codes: H = work hardened, T6 = solution heat treated and artificially aged, T3 = solution treated and cold worked. Density in kg/m3; the ksi columns are converted from MPa.

How to use this table

Choose the alloy by the job: strength, corrosion, welding and machining all pull in different directions.
Read the yield and tensile strength for the temper you are buying (strength drops after welding on heat-treated alloys).
Use the density for weight, and the specific strength (strength ÷ density) to compare with steel.

Worked example: strength for weight

6061-T6: yield 276 MPa ÷ density 2 700 kg/m³ = 102 kN·m/kg.
7075-T6: 503 ÷ 2 810 = 179 kN·m/kg, about 1.8 times better than 6061.
Mild steel A36 (250 MPa, 7 850 kg/m³) is only 32 kN·m/kg, so 6061-T6 gives about 3.2 times the strength per kilogram.

Notes and cautions

Welding a heat-treated alloy (6061-T6) lowers the strength next to the weld by 30 to 40 percent unless the part is heat treated again.
5052 and 5083 are the best for marine use and the cheapest to weld; 2024 and 7075 are strong but poor in corrosion resistance and not fusion welded.
Typical values only: minimum values in the standards are lower, and thick plate, extrusions and castings differ.

FAQ

Which aluminum is the strongest?

7075-T6 is the strongest common alloy (about 570 MPa tensile). It is hard to weld and less corrosion resistant than 5xxx and 6xxx alloys.

Which aluminum alloy is best for welding?

5052 and 5083 weld very well and keep their strength; 6061 welds well but loses strength next to the weld unless re-heat-treated.

What does T6 mean?

Solution heat treated, then artificially aged. It is the common high-strength temper of 6xxx and 7xxx alloys.

Sources

Aluminum Association, Aluminum Standards and Data; ASM Handbook, Volume 2; ASTM B209 (sheet and plate). Typical values for the named temper.
Typical room-temperature values for the named temper (ASM Handbook, Aluminum Association "Aluminum Standards and Data"; minimums in the standards are lower). Temper codes: H = work hardened, T6 = solution heat treated and artificially aged, T3 = solution treated and cold worked. Density in kg/m3; the ksi columns are converted from MPa.