Aluminum 7075 · temper
Aluminum 7075-O
Properties of the O condition, compared with the other 7075 tempers.
Softest condition for deep forming, severe bending or cold heading; must be solution treated and aged afterwards to develop strength.
What is 7075-O?
7075-O is 7075 in the O temper — softest condition for deep forming, severe bending or cold heading; must be solution treated and aged afterwards to develop strength. 7075-O has a yield strength of 103 MPa (14.9 ksi) and a tensile strength of 228 MPa (33.1 ksi) — weaker than 84% of aluminum grades. Elongation at break is 17% and the elastic modulus is 71.7 GPa (10.4 Msi). 7075-O has a density of 2.81 g/cm³ (0.102 lb/in³), heavier than 86% of aluminum grades. It melts at 477°C (891 °F). T6 is the default condition FabDigit quotes; O is available on request or by drawing note.
Advantages
- High electrical conductivity — 45 % IACS, better than 86% of aluminum grades
- Ductile — tolerates forming and impact — 17%, better than 85% of aluminum grades
- Conducts heat well — 173 W/m·K (100 BTU/hr·ft·°F), better than 84% of aluminum grades
- Forms and bends easily — 70/100, better than 83% of aluminum grades
Limitations
- Difficult to weld — 18/100, worse than 94% of aluminum grades
- Low strength — 103 MPa (14.9 ksi), worse than 84% of aluminum grades
7075-O properties
Typical room-temperature values for 7075-O — 15 properties are specific to this condition; the rest are grade-level values shared by every 7075 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
7075-O has a density of 2.81 g/cm³ (0.102 lb/in³), heavier than 86% of aluminum grades. It melts at 477°C (891 °F).
Mechanical16
7075-O has a yield strength of 103 MPa (14.9 ksi) and a tensile strength of 228 MPa (33.1 ksi) — weaker than 84% of aluminum grades. Elongation at break is 17% and the elastic modulus is 71.7 GPa (10.4 Msi).
Thermal6
7075-O is rated for continuous service to 150°C (302 °F). It conducts heat at 173 W/m·K (100 BTU/hr·ft·°F), better than 84% of aluminum grades. Thermal expansion is 23.6 µm/m·K (13.1 µin/in·°F).
Electrical3
7075-O conducts electricity at 45 % IACS, better than 86% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 62% of aluminum grades.
Sustainability4
Producing a kilogram of 7075-O takes about 205 MJ of energy and emits 12.5 kg of CO₂ — more than 75% of aluminum grades. Typical recycled content is 15%.
Manufacturability7
7075-O's machinability is fair (45/100, worse than 72% of aluminum grades); weldability poor (18/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 7075 tempers and conditions
7075 is also supplied in 12 other conditions. The full side-by-side table is on the 7075 overview.
- T6DefaultPeak-strength condition for extrusions, bar and forgings where maximum static strength matters and SCC exposure is controlled.503 MPa yield · 150 HB
- T651Standard stocked plate temper: peak strength with low residual stress, so machined parts stay flat.503 MPa yield · 150 HB
- T7651Plate temper balancing near-T6 strength, low residual stress and good exfoliation resistance for machined skins and spars.469 MPa yield · 145 HB
- T76Intermediate overage: better exfoliation resistance than T6 while keeping most of its strength (less SCC-resistant than T73).469 MPa yield · 145 HB
- T652Peak-aged 7075 hand/die forgings and blocks given a controlled compressive set to relieve quench stresses, giving near-T6 strength with reduced machining distortion.440 MPa yield · 150 HB
- T73Choose when stress-corrosion cracking resistance in the short-transverse direction is critical; ~12 % lower strength than T6.435 MPa yield · 135 HB
- T7351Standard SCC-resistant thick-plate temper for machined aerospace bulkheads and ribs.435 MPa yield · 135 HB
- T7Generic overaged 7075 condition that trades some peak strength for markedly better stress-corrosion-cracking resistance and dimensional stability.400 MPa yield · 135 HB
- T7352T73-type overaged forgings compressively stress-relieved for low residual stress, high SCC immunity and good short-transverse toughness.395 MPa yield · 135 HB
- OSoftest condition for deep forming, severe bending or cold heading; must be solution treated and aged afterwards to develop strength.103 MPa yield · 60 HB
Working with 7075-O
Is 7075 easy to machine?
Excellent chip control in T6/T651 — run high SFM with sharp polished-flute carbide, 2–3 flutes, generous coolant; leave symmetric stock and rough/finish in passes on T6 plate to avoid distortion (T651/T7351 are preferred for heavy metal removal).
Can 7075 be welded?
Not recommended for arc fusion welding (severe hot cracking and HAZ SCC); join by mechanical fastening, adhesive bonding, or friction-stir welding, and use 7xxx-compatible fillers only for repair of non-critical parts.
Can 7075 be formed, bent or molded?
Form in O or freshly solution-treated (W) condition then age; T6/T651 tolerates only large-radius bends (≥4–6 t) and cracks readily in tight cold forms.
What surface finishes work on 7075?
Takes Type II and Type III hard anodising well (grey/bronze tone, up to ~50 µm); chromate/trivalent conversion coating plus epoxy primer is standard for corrosion protection; shot peening improves fatigue and SCC life.
7075 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 |
|---|---|---|
| Znprincipal strengthening addition | 5.1 – 6.1 | 5.6 |
| Mg | 2.1 – 2.9 | 2.5 |
| Curaises strength, lowers corrosion resistance | 1.2 – 2 | 1.6 |
| Crgrain-structure control; SCC resistance | 0.18 – 0.28 | 0.23 |
| Feimpurity max | ≤ 0.5 | 0.25 |
| Siimpurity max | ≤ 0.4 | 0.15 |
| Mn | ≤ 0.3 | 0.05 |
| Ti | ≤ 0.2 | 0.03 |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
7075-O — frequently asked
What is 7075-O used for?
7075-O is typically used for aerospace components, defense equipment and gears. In short: ultimate strength; aerospace favorite.
What is the yield strength of 7075-O?
7075-O has a typical yield strength of 103 MPa (14.9 ksi) and a tensile strength of 228 MPa (33.1 ksi) — weaker than 84% of aluminum grades. Strength varies by condition: see the 13 listed tempers.
Is 7075-O easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 72% of aluminum grades). Excellent chip control in T6/T651 — run high SFM with sharp polished-flute carbide, 2–3 flutes, generous coolant; leave symmetric stock and rough/finish in passes on T6 plate to avoid distortion (T651/T7351 are preferred for heavy metal removal).
Can 7075-O be welded?
Not readily — weldability is rated poor (18/100). Not recommended for arc fusion welding (severe hot cracking and HAZ SCC); join by mechanical fastening, adhesive bonding, or friction-stir welding, and use 7xxx-compatible fillers only for repair of non-critical parts.
What surface finishes work on 7075-O?
Takes Type II and Type III hard anodising well (grey/bronze tone, up to ~50 µm); chromate/trivalent conversion coating plus epoxy primer is standard for corrosion protection; shot peening improves fatigue and SCC life.
Can 7075-O be formed, bent or molded?
Form in O or freshly solution-treated (W) condition then age; T6/T651 tolerates only large-radius bends (≥4–6 t) and cracks readily in tight cold forms.
What is the maximum service temperature of 7075-O?
7075-O is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 7075-T6 and 7075-O?
T6 is the default condition — peak-strength condition for extrusions, bar and forgings where maximum static strength matters and SCC exposure is controlled. O: softest condition for deep forming, severe bending or cold heading; must be solution treated and aged afterwards to develop strength. Yield strength is 503 MPa in T6 versus 103 MPa in O.
Can FabDigit make parts in 7075-O?
Yes — 7075-O is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Aluminum Standards and Data / Teal Sheets (Registration Record of Alloys) — The Aluminum Association (2018)
- ASTM B209 / B211 / B221 — aluminium sheet, plate, bar and extrusions — ASTM International (2021)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- MMPDS-17 Metallic Materials Properties Development and Standardization — Battelle/FAA (2022)
- 7075 plate and extrusion datasheets — Kaiser Aluminum / Constellium (2023)
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.