The tensile strength of aluminum is not one fixed number. It ranges from about 60 MPa for soft 1xxx-series material to more than 600 MPa for specialized high-strength tube. Alloy, temper, product form, thickness, and test direction all affect the reported value.
Common reference points include about 230 MPa for 5052-H32 tube, at least 260 MPa for standard 6061-T6 extrusion, and about 572 MPa for 7075-T651 rod or bar. These figures are useful for comparison. They are not interchangeable design allowables.
Aluminum tensile strength chart
The table below uses traceable manufacturer data. It deliberately mixes typical and minimum values because both appear in engineering work.
| Alloy and temper | Product basis | Ultimate tensile strength | Yield strength or 0.2% proof stress |
|---|---|---|---|
| 1060-O | Extrusion | 60-95 MPa (8.7-13.8 ksi) | 15 MPa minimum (2.2 ksi) |
| 1100-O | Extrusion | 75-105 MPa (10.9-15.2 ksi) | 25 MPa minimum (3.6 ksi) |
| 5052-H32 | Tube and pipe | 230 MPa (33 ksi) | 195 MPa (28 ksi) |
| 6063-T5 | Extrusion | 145-150 MPa (21-22 ksi) | Depends on wall thickness |
| 6063-T6 | Extrusion | 205 MPa (30 ksi) | Depends on wall thickness |
| 6061-T6/T651 | Extrusion | 260 MPa (38 ksi) | 240 MPa (35 ksi) |
| 6082-T6 | EN extrusion | 290-310 MPa (42-45 ksi) | 250-260 MPa (36-38 ksi) |
| 7075-T651 | Rod and bar | 572 MPa (83 ksi) | 503 MPa (73 ksi) |
The table is a comparison tool, not a substitute for a material standard. Even the same alloy and temper can have different requirements for sheet, plate, bar, tube, or extrusion. Thick and thin sections may also carry different minimums.
Tensile strength, yield strength, and breaking strength
Ultimate tensile strength, or UTS, is the highest engineering stress reached during a tensile test. It is calculated from the maximum load divided by the specimen’s original cross-sectional area:
UTS = maximum tensile load / original cross-sectional area
Yield strength marks the onset of permanent deformation. Aluminum often has no sharp yield point, so specifications commonly use 0.2% offset yield strength. European documents may call this 0.2% proof stress.
Breaking strength is the engineering stress when the specimen fractures. It may be lower than UTS because a ductile specimen begins to neck after reaching maximum load.
For most static designs, yield or proof strength controls the first unacceptable permanent deformation. UTS still matters for material comparison, quality control, and fracture-related checks. Neither value should be used without the applicable design rules.
Point f on the curve in the figure is the tensile strength point.
Why the value changes so much
Alloy composition and strengthening route
Magnesium strengthens 5xxx alloys through solid-solution strengthening and strain hardening. The 2xxx, 6xxx, and 7xxx families can gain substantial strength through precipitation heat treatment.
A 6061 product in the O temper behaves very differently from 6061-T6. Likewise, 5052-H32 reflects a defined amount of strain hardening and stabilization.
Temper and processing method
Cold work usually raises tensile and yield strength while reducing ductility. Solution heat treatment and aging can strengthen heat-treatable alloys. Uncontrolled heating may reverse part of that benefit.
Machining and anodizing do not turn a base alloy into a stronger temper. They can affect local geometry, residual stress, fatigue behavior, or surface performance. They do not justify replacing the certified bulk tensile value.
Product form, section size, and direction
Rolling, extrusion, drawing, and forging create different microstructures and textures. Specifications therefore separate sheet, plate, rod, bar, tube, forgings, and extrusions. Test direction can matter because wrought products are anisotropic.
Section size matters too. A thick extrusion may cool and age differently from a thin wall. This is why the 6063 and 6082 data above divide requirements by wall thickness and profile geometry.
How aluminum tensile strength is tested
A machined or full-section specimen is pulled under controlled uniaxial load. The test records load and extension until fracture. Original dimensions convert load into engineering stress, while an extensometer measures strain over a defined gauge length.
North American aluminum product specifications often reference ASTM B557 or B557M. ASTM notes that a standardized specimen may not fully represent the entire end product. General metallic testing may instead reference ASTM E8/E8M. European and international work commonly uses ISO 6892-1 for room-temperature testing.
A usable report should identify the standard and specimen orientation. It should also state alloy, temper, product form, dimensions, and test temperature. Results normally include UTS, yield or proof strength, and elongation.
One specimen does not define every part in a shipment. Acceptance criteria come from the purchase specification, sampling plan, and required lot traceability. Our overview of material testing in aluminum processing explains how tensile results fit beside chemistry, hardness, dimensional, and surface checks.
What happens after welding or at elevated temperature
Room-temperature base-metal data should not be carried blindly into a welded design. Fusion welding can soften the heat-affected zone of precipitation-hardened 6xxx alloys. Hydro’s 6061 and 6063 data sheets both flag reduced T6 properties near welds.
The amount of reduction depends on alloy, temper, welding process, heat input, filler, joint geometry, and any post-weld treatment. Use the governing structural code or qualified joint data. Do not assign the unwelded T6 value to the local heat-affected zone.
Temperature creates a similar scope problem. The table above is room-temperature data. If a component will carry load while hot, use temperature-specific strength data and the applicable code. A room-temperature certificate does not establish elevated-temperature capacity.
How to choose the right strength value
Start with the part, not with a generic chart.
- Define the load case and failure limit. Decide whether yielding, ultimate failure, fatigue, buckling, or joint behavior governs.
- Fix the alloy, temper, and product form. Include wall or plate thickness and any required grain direction.
- Identify the applicable material and design standards. Do this for the destination market and end use.
- Use the correct property class. Keep typical, minimum, and design values separate.
- Account for manufacturing. Review forming, welding, heat treatment, machining, and service temperature.
- Specify verification. State the required certificate, lot traceability, sampling, and test method on the drawing or purchase order.
This sequence prevents a common sourcing error: selecting an alloy from a high UTS value, then buying a different temper or product form. It also keeps strength from crowding out corrosion resistance, formability, weldability, finish, and cost. Our guide to choosing an aluminum extrusion alloy covers those trade-offs in more detail.
What to request from an aluminum supplier
For a strength-critical part, send more than an alloy number. A useful request includes:
- drawing and revision;
- alloy, temper, and product specification;
- product form and critical section thickness;
- minimum yield and tensile requirements, if the specification does not already control them;
- test standard, direction, sampling, and acceptance criteria;
- certificate and lot-traceability requirements;
- welding, heat treatment, surface finish, and service-temperature conditions.
Ask whether quoted properties are typical or guaranteed minimums. Also confirm whether the certificate reports actual lot results or only specification limits.
Conclusion: Use a Specification-Based Tensile Strength
Use a value tied to a recognized product specification, not the highest number in a general table. State the full alloy and temper, product form, thickness range, test direction, and required evidence. For welded or hot-service parts, add the rules that govern the affected condition.
That definition gives the designer, manufacturer, and test laboratory the same acceptance target. It is far more useful than asking for “strong aluminum.”
Frequently asked questions
What is the tensile strength of pure aluminum?
There is no single value for “pure aluminum.” Annealed commercial-purity 1060 and 1100 extrusions in Hydro’s data range from about 60 to 105 MPa. Cold-worked 1xxx products can be stronger, so purity, temper, and form must be stated.
What is the tensile strength of 6061-T6 aluminum?
A common minimum for 6061-T6/T6511 extrusion is 260 MPa, or 38 ksi. Sheet, plate, bar, tube, and special extrusion classes may use different requirements. Check the controlling product specification and thickness range.
Is 7075 the strongest aluminum alloy?
7075-T651 is a common high-strength reference at about 572 MPa typical UTS for rod and bar. It is not the absolute limit of aluminum. Specialized alloys and product specifications can exceed 600 MPa. Availability, toughness, corrosion behavior, formability, and cost may be less favorable.
Is aluminum weaker than steel?
Most aluminum alloys have lower absolute stiffness and strength than common structural steels. Aluminum is about one-third the density, so strength-to-weight comparisons can tell a different story. The final choice also depends on section geometry, corrosion, joining, production volume, and cost.
