Aluminum Temper Meaning and Chart

Aluminum alloy temper directly determines the material's strength, ductility, corrosion resistance, internal stress, and workability. Therefore, understanding aluminum alloy tempers helps you choose the right material, apply the correct processing methods, and control costs effectively.

1. What is Aluminum Alloy Temper?

Aluminum Alloy Temper refers to the final mechanical properties and internal microstructure of aluminum products, formed through different processing procedures including rolling, extrusion, annealing, quenching, aging and cold working.

In short, for the same alloy grade (such as 6061), different tempers lead to completely different strength, hardness, ductility and corrosion resistance.

• Alloy Grade = "Material Composition Formula" (e.g. 6061, 7075)

• Temper = "Processing & Heat Treatment Formula" (e.g. O, H14, T6)

2. Five Basic Tempers Designations

In accordance with the national standard GB/T 16475, wrought aluminum alloys are divided into five basic tempers: F, O, H, W, T.

1) F - As Fabricated (Free Processing Temper)

• Processing: Delivered directly after rolling/extrusion, without any additional heat treatment or intentional hardening

• Performance: Unstable strength, good ductility, no internal stress control requirements

• Applications: Common plates and profiles with low performance requirements, requiring extensive subsequent processing

2) O - Annealed Temper

• Processing: Heated to recrystallization temperature, held, and slowly cooled to eliminate processing stress and soften grains

• Performance: Softest, lowest strength, best ductility, ideal for bending and deep drawing

• Applications: Aluminum cookware, decorative sheets, deep-drawn parts, complex bending component

3) H - Strain Hardened (Cold Worked) Temper

• Processing: Strengthened by cold rolling, cold drawing or straightening, through grain deformation and lattice distortion

• Applicable alloys: Non-heat-treatable alloys (1xxx, 3xxx, 5xxx series)

• Performance: Strength increases with cold working degree, while ductility decreases

4) W - Solution Heat Treated (Unstable Temper)

• Processing: A temporary state after solution quenching and during natural aging

• Features: Unstable, not used as a delivery temper, only indicates the material is in natural aging

5) T - Thermally Heat Treated (Stable Strengthened) Temper

• Processing: Solution treatment (high-temperature dissolution of alloy elements) → Quenching (rapid locking) → Aging (precipitation of strengthening phases)

• Applicable alloys: Heat-treatable alloys (2xxx, 6xxx, 7xxx, 8xxx series)

• Performance: Highest strength, high hardness, excellent comprehensive performance, core material for aerospace and automotive industries

3. Aluminum Temper Codes 

1) Standard Origin

This temper system was developed by the Aluminum Association (AA, USA), later standardized as ANSI H35.1, and equivalently adopted by China's national standard GB/T 16475.

2) Naming Structure

• Basic temper: Single letter → F, O, H, W, T

• Detailed temper: Letter + 1-3 digitsH series: H + two digits (1st digit = processing type, 2nd digit = hardening degree)

• T series:T + 1-10 digits + optional suffix (1st digit = heat treatment type, suffix = special treatment)

 4. Aluminum Two Main Tempers Interpretation

1) H Temper Interpretation (Strain Hardened, Non-Heat-Treatable Alloys)

Standard Format: HXY

1st Digit X: Processing Type

• H1X: Pure cold working hardening (no annealing, no stabilization)

• H2X: Cold working + partial annealing (slightly reduced strength, recovered ductility)

• H3X: Cold working + stabilization (low-temperature stress relief, prevents room-temperature aging softening)

• H4X: Cold working + painting/coating treatment

2nd Digit Y: Hardening Degree (Higher Number = Harder Material)

• ×1: 1/4 hard (between O temper and full hard, softer side)

• ×2: 1/2 hard

• ×3: 3/4 hard

• ×4: Full hard (H18)

• ×8: Extra hard

• ×9: Super hard

Examples

• 5052-H32: Al-Mg alloy, cold working + stabilization, 1/2 hard → Marine sheets, automotive outer panels

• 1100-H14: Pure aluminum, pure cold hardening, full hard → Nameplates, decorative panels

2) T Temper Interpretation (Heat Treated, Heat-Treatable Alloys)

T temper designation standard format:TX / TXX / TX51…

1st Digit (1-10): Core Heat Treatment Process

• T1: Cooled from hot forming (extrusion/rolling) → Naturally aged

• T2: Cooled from hot forming → Cold worked → Naturally aged

• T3: Solution quenched → Cold worked → Naturally aged

• T4: Solution quenched → Naturally aged (most common, excellent ductility)

• T5: Cooled from hot forming → Artificially aged

• T6: Solution quenched → Artificially aged (highest strength, most widely used)

• T7: Solution quenched → Overaged (slightly reduced strength, improved corrosion/stress corrosion resistance)

• T8: Solution quenched → Cold worked → Artificially aged

• T9: Solution quenched → Artificially aged → Cold worked

• T10: Cooled from hot forming → Cold worked → Artificially aged

Suffix (51, 52, 511): Stress Relief & Straightening

• 51: Stress relief by stretch straightening (commonly used for plates and thick plates)

• 52: Compression straightening

• 511: Minor stretch straightening

Examples

• 6061-T6: Solution treatment + artificial aging → Structural parts, profiles, bicycle frames

• 7075-T651: Solution treatment + artificial aging + stretch stress relief → Aerospace structures, molds

• 2A12-T4: Solution treatment + natural aging → Aircraft skins, frames

on treatment (high-temperature dissolution of alloy elements) → Quenching (rapid locking) → Aging (precipitation of strengthening phases)

• Applicable alloys: Heat-treatable alloys (2xxx, 6xxx, 7xxx, 8xxx series)

• Performance: Highest strength, high hardness, excellent comprehensive performance, core material for aerospace and automotive industries

5. Common Aluminum Alloy Series + Typical Temper + Applications 

1xxx Series - Pure Aluminum (Non-Heat-Treatable)

• 1050-O: Soft pure aluminum → Aluminum foil, tableware, decorative parts

• 1070-H14: Medium-hard pure aluminum → Conductive busbars, heat sinks

2xxx Series - Al-Cu Alloy (Duralumin, Heat-Treatable)

• 2A12-T4 / T6 → Aircraft skins, frames, rivets

• 2024-T3 / T4 → Aircraft structural parts, high-fatigue components

3xxx Series - Al-Mn Alloy (Anti-Corrosion, Non-Heat-Treatable)

• 3003-H14 / H18 → Anti-corrosion sheets, cookware, can bodies

• 3004-H19 → Can lids

5xxx Series - Al-Mg Alloy (Anti-Corrosion, Non-Heat-Treatable)

• 5052-H32 / H34 → Marine sheets, automotive outer panels, fuel tanks

• 5083-O / H112 → Welded structures, marine plates, pressure vessels

• 5754-H22 → Automotive inner panels, lightweight structures

6xxx Series - Al-Mg-Si Alloy (Wrought Aluminum, Heat-Treatable, Most Universal)

• 6061-T6 → Architectural profiles, automotive parts, bicycle frames, molds

• 6063-T5 / T6 → Door & window profiles, curtain walls, decorative profiles

• 6082-T6 → High-strength structural profiles, rail transit components

7xxx Series - Al-Zn-Mg-Cu Alloy (Super Duralumin, Heat-Treatable)

• 7075-T6 / T651 → Aircraft landing gears, molds, high-strength structures

• 7050-T7451 → High toughness, stress corrosion resistant → Key aerospace components