Aluminum alloy tempers refer to the different mechanical and thermal treatments applied to aluminum to achieve specific properties such as strength, hardness, ductility, and corrosion resistance. Common tempers include O (annealed), H (strain-hardened), and T (heat-treated), each designed for different industrial applications such as marine engineering, building construction, and transportation equipment.
What Are Aluminum Alloy Tempers?
Aluminum alloy tempers are defined as the specific processing conditions assigned to an alloy under international standards like ASTM and EN. The temper designation follows the alloy number (for example, 5083-H116 or 6061-T6) to indicate exactly how the material was processed at the mill.
Understanding the aluminum temper meaning is crucial for manufacturers and engineers because the temper dictates the material's final performance. A single alloy grade can exhibit completely different physical characteristics depending on its temper. The temper system primarily controls three critical factors:
- Strength control: Determining the yield and tensile strength required for structural load-bearing.
- Formability: Dictating how much the aluminum plate can be bent, stamped, or drawn without cracking.
- Corrosion resistance: Adjusting the internal grain structure to resist harsh environments, such as seawater or chemical exposure.
Main Aluminum Temper Categories Explained for Aluminum
The aluminum alloy designation system uses letters to indicate the basic treatment process, followed by numbers that indicate specific processing variations. Here is a detailed breakdown of the primary tempers.
| Temper | Description |
|---|---|
| H | Strain-Hardened Temper: Applies to products strengthened through cold working (strain hardening). The product may undergo additional thermal treatment after strain hardening, with or without a reduction in strength. |
| O | Annealed Temper: Applies to wrought products that have been fully annealed to obtain the lowest strength condition and maximum ductility. |
| T | Heat-Treated Temper: Different from F, O, and H tempers. Applies to products that are thermally treated, with or without strain hardening, to produce stable tempers. The T designation must be followed by one or more digits (commonly used for heat-treatable alloys). |
| W | Solution Heat-Treated Temper: An unstable temper applicable only to alloys that have been solution heat-treated and naturally aged at room temperature. This designation indicates the product is in a transient condition. |
| F | As-Fabricated Temper: Applies to products shaped during manufacturing processes where no special control over thermal or strain hardening conditions is required. Mechanical properties are not specified. |
H Temper (Strain-Hardened) for Aluminum
The H temper is defined as a condition where the strength of the aluminum is increased through cold working (strain hardening), such as rolling the metal at room temperature. This temper is primarily used for non-heat-treatable alloys, including the 1xxx, 3xxx, and 5xxx series.
The H code structure consists of two to three digits:
- H1 (Strain hardened only): The metal is cold-rolled to the desired dimension without any subsequent thermal treatment.
- H2 (Strain hardened and partially annealed): The metal is cold-worked beyond the required final strength, then heated slightly to soften it back to the target strength level, improving ductility.
- H3 (Strain hardened and stabilized): The metal is cold-worked and then subjected to a low-temperature heating process to stabilize its mechanical properties and prevent age softening.
- H4 is the temper of work hardening and painting. It applies to products that have undergone work hardening and painting, resulting in incomplete annealing.
The second digit in the H temper designation indicates the degree of strain hardening achieved in the material.
Generally, the strain hardening level is divided into 8 grades, where:
1 = lowest hardness
8 = highest hardness (full hard)
9 = extra hard condition beyond Hx8
H1x Series – Strain Hardened Only
| Temper | Description |
|---|---|
| H12 | Strain hardened to approximately 25% of full hardness |
| H14 |
Strain hardened to approximately 50% of full hardness |
| H16 | Strain hardened to approximately 75% of full hardness |
| H18 | Strain hardened to 100% (full hard condition) |
| H19 | Extra strain hardened condition; tensile strength is at least 10 N/mm² higher than H18 |
H2x Series – Strain Hardened and Partially Annealed
| Temper | Description |
|---|---|
| H22 | Strain hardened and then partially annealed to 25% hardness |
| H24 | Strain hardened and then partially annealed to 50% hardness |
| H26 | Strain hardened and then partially annealed to 75% hardness |
| H28 | Strain hardened and then partially annealed to 100% hardness |
H3x Series – Strain Hardened and Stabilized
| Temper | Description |
|---|---|
| H32 |
Strain hardened and stabilized to 25% hardness |
| H34 |
Strain hardened and stabilized to 50% hardness Read more:5052 H34 |
| H36 | Strain hardened and stabilized to 75% hardness |
| H38 | Strain hardened and stabilized to 100% hardness |
H4x Series – Strain Hardened and Painted
| Temper | Description |
|---|---|
| H42 | Strain hardened and lacquered/painted, 25% hardness |
| H44 | Strain hardened and lacquered/painted, 50% hardness |
| H46 | Strain hardened and lacquered/painted, 75% hardness |
| H48 | Strain hardened and lacquered/painted, 100% hardness |
Special HXXX Tempers in Aluminum Alloys
| Temper | Description |
|---|---|
| H111 |
Applies to products that have undergone final annealing followed by a slight amount of strain hardening, but the degree of strain hardening is less than that required for H11 temper. |
| H112 |
Applies to products that are formed by hot working processes. Mechanical properties are specified and meet standard requirements, although the exact degree of strain hardening is not controlled. Read more:5083-H112, 5A06 H112 Aluminum Plate |
| H116 |
Applies to 5XXX series alloys with magnesium content ≥ 4.0%. These products meet specified mechanical properties and provide enhanced resistance to exfoliation corrosion, making them ideal for marine environments. |
| H321 |
Applies to products that are strain hardened and then stabilized by a low-temperature thermal treatment. This temper improves resistance to stress corrosion and microstructural instability, while maintaining mechanical properties similar to H32. Read more:5083 H321 Aluminum Plate |
T Temper Subdivisions (TX Tempers) in Aluminum Alloys
In the T temper designation system, the digit following "T" (0–10) indicates the specific sequence of thermal and mechanical treatments applied to the product.
T0 – T10 Tempers
| Temper | Description |
|---|---|
| T0 | Applies to products that are solution heat-treated, naturally aged, and then cold worked to increase strength. |
| T1 | Applies to products that are cooled from an elevated temperature shaping process and naturally aged to a substantially stable condition, without further cold working (straightening or flattening is allowed if it does not significantly affect mechanical properties). |
| T2 | Applies to products that are cooled from an elevated temperature shaping process, cold worked, and then naturally aged to a substantially stable condition. |
| T3 | Applies to products that are solution heat-treated, cold worked, and then naturally aged to a substantially stable condition. |
| T4 |
Applies to products that are solution heat-treated and naturally aged to a substantially stable condition, without further cold working (straightening or flattening is allowed if it does not significantly affect mechanical properties). Read more:6061 T4 Aluminum Tube |
| T5 |
Applies to products that are cooled from an elevated temperature shaping process and then artificially aged, without cold working (straightening or flattening is allowed if it does not significantly affect mechanical properties). Read more:6005 T5 Aluminum Rectangular Tube ,6063-T5 Aluminum Pipe |
| T6 |
Applies to products that are solution heat-treated and then artificially aged, without further cold working (straightening or flattening is allowed if it does not significantly affect mechanical properties). Read more:6061 T6 Aluminum Tube, 6082 T6 Aluminum Plate |
| T7 | Applies to products that are solution heat-treated and then overaged (artificially aged beyond peak strength) to obtain specific properties such as improved corrosion resistance or dimensional stability. |
| T8 | Applies to products that are solution heat-treated, cold worked, and then artificially aged to increase strength. |
| T9 | Applies to products that are solution heat-treated, artificially aged, and then cold worked to further increase strength. |
| T10 | Applies to products that are cooled from an elevated temperature shaping process, cold worked, and then artificially aged to achieve higher strength. |
TXX and TXXX Tempers in Aluminum Alloys
These tempers indicate that the product has undergone special processing treatments that significantly modify its properties, such as mechanical strength, corrosion resistance, or stress corrosion behavior.
| Temper | Description |
|---|---|
| T42 | Applies to products that are solution heat-treated from O or F temper and naturally aged to a stable condition. Also applies to products heat-treated from any temper to achieve mechanical properties equivalent to T42. |
| T62 | Applies to products that are solution heat-treated from O or F temper and then artificially aged. Also applies to products heat-treated from any temper to achieve mechanical properties equivalent to T62. |
| T73 | Applies to products that are solution heat-treated and then overaged to achieve specified mechanical properties and improved stress corrosion resistance. |
| T74 | Similar to T73, but with higher tensile strength than T73 and lower than T76, while maintaining good stress corrosion resistance. |
| T76 | Similar to T73, but with higher tensile strength than T73 and T74, and lower stress corrosion resistance, while still maintaining good exfoliation corrosion resistance. |
| T7X2 | Applies to products that are solution heat-treated from O or F temper and then artificially overaged, achieving mechanical and corrosion properties equivalent to T7X tempers. |
| T81 | Applies to products that are solution heat-treated, cold worked (~1% deformation), and then artificially aged to increase strength. |
| T87 | Applies to products that are solution heat-treated, cold worked (~7% deformation), and then artificially aged for higher strength. |
Stress-Relieved Tempers in Aluminum Alloys
(Suffixes "51", "510", "52", "54" are added after TX / TXX / TXXX tempers to indicate stress-relief treatment.)
-51 Tempers (TX51 / TXX51 / TXXX51)
| Item | Description |
|---|---|
| Process | Stress relieved by stretching after solution heat treatment or cooling from an elevated temperature shaping process |
| Applicable Products | Plate, rolled or cold-finished bars, die forgings, forging rings, and rolled rings |
| Post-Treatment | No further straightening after stretching |
| Permanent Set | Plate: 1.5% – 3% |
| Rolled or cold-finished bars: 1% – 3% | |
| Die forgings / forging rings / rolled rings: 1% – 5% |
Read more:6061-T651 Aluminum Alloy Plate,7075-T651 Aluminum plate
-510 Tempers (TX510 / TXX510 / TXXX510)
| Item | Description |
|---|---|
| Process | Stress relieved by stretching after solution heat treatment or cooling from an elevated temperature shaping process |
| Applicable Products | Extruded rods, bars, shapes, tubes, and drawn tubes |
| Post-Treatment | No further straightening after stretching |
| Permanent Set | Extruded rods, bars, shapes, tubes: 1% – 3% |
| Drawn tubes: 1.5% – 3% |
-52 Tempers (TX52 / TXX52 / TXXX52)
| Item | Description |
|---|---|
| Process | Stress relieved by compression after solution heat treatment or cooling from high-temperature forming |
| Applicable Products | Various wrought aluminum products |
| Permanent Set | 1% – 5% |
-54 Tempers (TX54 / TXX54 / TXXX54)
| Item | Description |
|---|---|
| Process | Stress relieved by cold sizing in the final forging die |
| Applicable Products | Die forgings |
O Temper (Annealed)
The O temper refers to the fully softened condition of aluminum alloys. It is achieved by heating the metal to a specific temperature and cooling it slowly. This temper provides the lowest strength but the highest ductility and formability.
Characteristics: Excellent workability, zero residual stress.
Typical Applications: Deep drawing processes, chemical equipment, and complex forming tasks where the metal must bend significantly without fracturing.
F Temper (As Fabricated)
The F temper is defined as the condition resulting from the normal manufacturing process (rolling, extruding, or casting) without any special control over thermal conditions or strain hardening. There are no guaranteed mechanical properties for F temper products, and they are usually purchased by buyers who will forge or heat-treat the material themselves.
W Temper (Solution Heat-Treated)
The W temper refers to an unstable condition following solution heat treatment. Because the metal naturally ages at room temperature over time, the W temper is rarely used for direct commercial supply and is mainly an intermediate manufacturing phase.
Aluminum Alloy Temper Chart for Industrial Applications
The following aluminum temper chart provides a quick reference to match temper states with their strength levels and standard industrial uses.
| Temper | Meaning | Strength Level | Typical Applications |
| O | Annealed (Fully softened) | Low | Deep forming, chemical tanks, piping |
| H32 | Strain hardened + stabilized (1/4 hard) | Medium | Tread plates, cabinet enclosures, general sheet metal |
| H116 | Marine grade strain hardened | Medium-High | Ship hulls, bulkheads, decks |
| H321 | Stabilized marine grade | High | Offshore structures, pressure vessels |
| T6 | Heat treated + artificially aged | High | Aerospace components, heavy structural parts |
| T651 | Heat treated + stress relieved | High | CNC machined parts, mold making |
How to Choose the Right Aluminum Temper for Your Project
Selecting the correct temper requires a balance between the desired mechanical strength, welding requirements, and bending parameters.
1. For Marine and Offshore Use
When building workboats, yachts, or offshore platforms, the material will face continuous saltwater exposure.
Recommendation: 5083 aluminum plate H116 or H321. These tempers guarantee that the magnesium within the alloy will not precipitate at the grain boundaries, thereby preventing intergranular and exfoliation corrosion.
2. For High Structural Strength and Machining
If you are manufacturing load-bearing frames, bridge components, or machinery bases, high yield strength is critical.
Recommendation: 6061-T6 or 7075-T651. If the part requires heavy CNC milling, always choose T651 to ensure the plate remains perfectly flat after material removal.
3. For Forming, Bending, and Stamping
When producing automotive panels, fuel tanks, or complex enclosures, the metal must not crack upon bending.
Recommendation: O temper or 5052-H32.
The choice of temper depends on the balance between strength, corrosion resistance, and formability required for the application. If you are unsure which temper matches your blueprint specifications, contact our engineering team today for a rapid technical review and a competitive wholesale quote.
Contact our engineering team today
GNEE Advantage
GNEE is a leading Chinese aluminum factory-direct supplier, specializing in industrial and marine grade aluminum. We do not just trade; we control the manufacturing process to ensure strict adherence to international temper standards.
Our Factory Capabilities & Authentic Industrial Data:
- Equipment: We operate a 3300mm wide "1+4" hot rolling line and an 4000-ton stretching machine. This heavy machinery allows us to produce ultra-wide marine plates (up to 2600mm width) and guarantee the flatness of T651 stress-relieved plates.
- Quality Control: Every batch of 5083 H116 and H321 marine aluminum alloy undergoes ASTM G66 (exfoliation corrosion) and ASTM G67 (intergranular corrosion) testing.
- Supply Capacity: We maintain a monthly production capacity of 900+ tons.
- Seaworthy Packaging: We understand the risks of maritime transport. All aluminum plates are interleaved with moisture-proof kraft paper, wrapped in waterproof plastic film, packed with industrial desiccants, and secured on fumigated wooden pallets.
- Real Use Case: In 2023, we supplied 150 tons of certified 5083-H116 aluminum plates to a shipyard in Singapore for patrol boat construction. The plates passed the ABS surveyor inspection on the first test, and the client reported zero cracking during tight-radius hull bending.
Whether you need 5083 aluminum plate H116 for shipbuilding or 6061-T651 for aerospace machining, GNEE provides multi-alloy supply, custom dimensions, and full marine certification support. Send us your material list and requested tempers now, and we will provide factory-direct pricing within 24 hours.