Aluminum 7A52-O (Annealed)
Temper
GB 7A52
Softest condition for heavy forming, deep drawing or straightening before solution treatment and ageing.
Values for the O condition
Other 7A52 tempers and conditions
7A52 is listed in 7 conditions; see the grade overview at 7A52.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
OThis page Annealed | Softest condition for heavy forming, deep drawing or straightening before solution treatment and ageing. | 140 | 250 | 17 | 70 HB | 46 % IACS |
As-welded deposit | Design value for welded armor hull joints (ER5356/ER5183 filler) without post-weld heat treatment; strength recovers with weeks of natural re-ageing. | 230 | 340 | 8 | 100 HB | 42 % IACS |
Solution heat treated and naturally aged | Pick for forming or welding operations followed by natural/artificial re-ageing; moderate strength with better ductility than T6. | 240 | 380 | 17 | 105 HB | 33 % IACS |
Solution heat treated and overaged for stress-corrosion resistance | Overaged option for thick sections in humid/marine or high-residual-stress service where stress-corrosion cracking resistance outweighs peak strength. | 330 | 405 | 14 | 118 HB | 43 % IACS |
Cooled from hot working and artificially aged | Used for extruded profiles and press-quenched sections where full re-solution treatment is impractical. | 340 | 420 | 12 | 122 HB | 41 % IACS |
T6, stress relieved by stretching | Choose for thick plate that will be extensively machined — same strength as T6 but low residual stress and minimal machining distortion. | 385 | 455 | 11 | 133 HB | 40 % IACS |
T6Default Solution heat treated and artificially aged | Standard supply condition for armor plate and welded structural panels — highest strength/ballistic performance with acceptable weld joint efficiency. | 390 | 460 | 12 | 135 HB | 40 % IACS |
What is 7A52-O?
7A52-O is 7A52 in the O temper — softest condition for heavy forming, deep drawing or straightening before solution treatment and ageing. 7A52-O has a yield strength of 140 MPa (20.3 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 70% of aluminum grades. Elongation at break is 17% and the elastic modulus is 70 GPa (10.2 Msi). 7A52-O has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 585°C (1,085 °F). T6 is the default condition FabDigit quotes; O is available on request or by drawing note.
Advantages
- Forms and bends easily — 85/100, better than 91% of aluminum grades
- High electrical conductivity — 46 % IACS, better than 87% of aluminum grades
- Ductile — tolerates forming and impact — 17%, better than 85% of aluminum grades
- Conducts heat well — 175 W/m·K (101.1 BTU/hr·ft·°F), better than 85% of aluminum grades
- Tough — resists crack growth — 32 MPa·√m (29.1 ksi·√in), better than 83% of aluminum grades
Limitations
- Difficult to machine — 40/100, worse than 81% of aluminum grades
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
7A52-O properties
Typical room-temperature values for 7A52-O; 10 are specific to this condition. Other listed values are 7A52 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
7A52-O has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 585°C (1,085 °F).
Mechanical13
7A52-O has a yield strength of 140 MPa (20.3 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 70% of aluminum grades. Elongation at break is 17% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
7A52-O is rated for continuous service to 120°C (248 °F). It conducts heat at 175 W/m·K (101.1 BTU/hr·ft·°F), better than 85% of aluminum grades. Thermal expansion is 23.5 µm/m·K (13.1 µin/in·°F).
Electrical3
7A52-O conducts electricity at 46 % IACS, better than 87% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), better than 62% of aluminum grades.
Sustainability4
Producing a kilogram of 7A52-O takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 20%.
Manufacturability7
7A52-O's machinability is fair (40/100, worse than 81% of aluminum grades); weldability very good (75/100); formability excellent (85/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 7A52-O
Is 7A52 easy to machine?
Machines like 7075-T6 — free-cutting with sharp carbide tools, high speeds, positive rake and flood coolant; use T651 plate to avoid distortion in thick machined parts.
Can 7A52 be welded?
Designed for GMAW/GTAW with ER5356 or ER5183 filler; keep heat input low, preheat ≤120 °C, expect HAZ softening that recovers by natural re-ageing, and avoid 4000 series (Si) fillers which embrittle Al-Zn-Mg joints.
Can 7A52 be formed, bent or molded?
Form in O or T4 and age afterwards; T6 plate tolerates only gentle bends (min radius ≈ 4–6 t) and should be warm-formed or hot-formed for tight radii.
What surface finishes work on 7A52?
Chromate/Ti-Zr conversion coat plus epoxy primer and topcoat is standard for vehicle hulls; clear or hard anodizing is possible but decorative color match is inconsistent, and shot peening of welds helps SCC/fatigue life.
7A52 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Znmain strengthening element with Mg | 4 – 4.8 | 4.4 |
| Mg | 2 – 2.8 | 2.4 |
| Mn | 0.2 – 0.5 | 0.35 |
| Crimproves SCC resistance | 0.15 – 0.25 | 0.2 |
| Zrgrain-structure control | 0.05 – 0.15 | 0.1 |
| Ti | 0.05 – 0.18 | 0.1 |
| Cukept low for weldability | 0.05 – 0.2 | 0.12 |
| Feimpurity | ≤ 0.3 | — |
| Siimpurity | ≤ 0.25 | — |
| Others (each)total 0.15 max | ≤ 0.05 | — |
| Al | balance | — |
7A52-O — frequently asked
What is 7A52-O used for?
7A52-O is typically used for armored vehicle hulls, welded structural panels and military plate. In short: weldable high-strength 7000 series; armor plate grade; best 7000-series corrosion resistance here.
What is the yield strength of 7A52-O?
7A52-O has a typical yield strength of 140 MPa (20.3 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 70% of aluminum grades. Strength varies by condition: see the 7 listed tempers.
Is 7A52-O easy to machine?
Not especially — machinability is rated fair (40/100, worse than 81% of aluminum grades). Machines like 7075-T6 — free-cutting with sharp carbide tools, high speeds, positive rake and flood coolant; use T651 plate to avoid distortion in thick machined parts.
Can 7A52-O be welded?
Yes — weldability is rated very good (75/100). Designed for GMAW/GTAW with ER5356 or ER5183 filler; keep heat input low, preheat ≤120 °C, expect HAZ softening that recovers by natural re-ageing, and avoid 4000 series (Si) fillers which embrittle Al-Zn-Mg joints.
What surface finishes work on 7A52-O?
Chromate/Ti-Zr conversion coat plus epoxy primer and topcoat is standard for vehicle hulls; clear or hard anodizing is possible but decorative color match is inconsistent, and shot peening of welds helps SCC/fatigue life.
Can 7A52-O be formed, bent or molded?
Form in O or T4 and age afterwards; T6 plate tolerates only gentle bends (min radius ≈ 4–6 t) and should be warm-formed or hot-formed for tight radii.
What is the maximum service temperature of 7A52-O?
7A52-O is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 7A52-T6 and 7A52-O?
T6 is the default condition — standard supply condition for armor plate and welded structural panels — highest strength/ballistic performance with acceptable weld joint efficiency. O: softest condition for heavy forming, deep drawing or straightening before solution treatment and ageing. Yield strength is 390 MPa in T6 versus 140 MPa in O.
Sources
- ASM Handbook Vol. 2: Properties and Selection — Nonferrous Alloys (7005/7039 data) — ASM International (1990)
- ASM Handbook Vol. 13B: Corrosion — Aluminum Alloys — ASM International (2005)
- Aluminum Association Teal Sheets — registered alloy compositions (7039/7005 comparison) — The Aluminum Association (2018)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.