Aluminum 7204-T73
Temper
AA 7204
T73 = solution heat treated and overaged for stress-corrosion resistance
Use where sustained tensile stress meets a chloride environment and SCC immunity outranks peak strength.
Values for the T73 condition
Other 7204 tempers and conditions
7204 is listed in 7 conditions; see the grade overview at 7204.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition, used for severe forming, deep bending or straightening before heat treatment. | 90 | 195 | 20 | 48 HB | 44 % IACS |
Solution heat treated and naturally aged | Pick when parts must be formed or welded after solution treatment; strength continues to climb slowly at room temperature. | 205 | 315 | 16 | 78 HB | 34 % IACS |
T73This page Solution heat treated and overaged for stress-corrosion resistance | Use where sustained tensile stress meets a chloride environment and SCC immunity outranks peak strength. | 265 | 320 | 13 | 90 HB | 42 % IACS |
Cooled from hot working and artificially aged | Economical press-quenched extrusion temper for thin sections where full solution treatment is not needed. | 285 | 340 | 11 | 95 HB | 37 % IACS |
T6Default Solution heat treated and artificially aged | Default structural condition: peak strength for welded frames, beams and forged fittings. | 300 | 355 | 11 | 100 HB | 38 % IACS |
T6, stress relieved by stretching | Choose for machined plate and bar parts that must stay flat and dimensionally stable after stock removal. | 305 | 355 | 10 | 102 HB | 38 % IACS |
T6, stress relieved by stretching, minor straightening | Standard stress-relieved extrusion temper for long straight profiles that will be heavily machined. | 305 | 355 | 10 | 100 HB | 38 % IACS |
What is 7204-T73?
7204-T73 is 7204 in the T73 temper — use where sustained tensile stress meets a chloride environment and SCC immunity outranks peak strength. 7204-T73 has a yield strength of 265 MPa (38.4 ksi) and a tensile strength of 320 MPa (46.4 ksi) — stronger than 69% of aluminum grades. Elongation at break is 13% and the elastic modulus is 70 GPa (10.2 Msi). 7204-T73 has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 605°C (1,121 °F). T6 is the default condition FabDigit quotes; T73 is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 36 MPa·√m (32.8 ksi·√in), better than 93% of aluminum grades
- High electrical conductivity — 42 % IACS, better than 81% of aluminum grades
- Ductile — tolerates forming and impact — 13%, better than 79% of aluminum grades
- Good corrosion resistance — 70/100, better than 79% of aluminum grades
- Readily welded — 82/100, better than 76% of aluminum grades
7204-T73 properties
Typical room-temperature values for 7204-T73; 11 are specific to this condition. Other listed values are 7204 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
7204-T73 has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 605°C (1,121 °F).
Mechanical13
7204-T73 has a yield strength of 265 MPa (38.4 ksi) and a tensile strength of 320 MPa (46.4 ksi) — stronger than 69% of aluminum grades. Elongation at break is 13% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
7204-T73 is rated for continuous service to 150°C (302 °F). It conducts heat at 155 W/m·K (89.6 BTU/hr·ft·°F), better than 71% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).
Electrical3
7204-T73 conducts electricity at 42 % IACS, better than 81% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 79% of aluminum grades.
Sustainability4
Producing a kilogram of 7204-T73 takes about 205 MJ of energy and emits 12.5 kg of CO₂ — more than 76% of aluminum grades. Typical recycled content is 30%.
Manufacturability8
7204-T73's machinability is good (56/100, worse than 55% of aluminum grades); weldability very good (82/100); formability poor (32/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 7204-T73
Is 7204 easy to machine?
Machines cleanly in T5/T6 with sharp polished-flute carbide tooling, high speed and generous coolant; annealed stock is gummy and gives poor finish.
Can 7204 be welded?
One of the best-weldable 7000-series alloys — MIG/TIG with 5356 or 5183 filler; the HAZ naturally re-ages to about 75–85 % of parent strength in 30–90 days, and a 24 h/120 °C post-weld age restores more.
Can 7204 be formed, bent or molded?
Form, bend and stretch in O or freshly quenched T4 (refrigerate to delay ageing); T6 sections crack at tight radii and should be bent to at least 4–6 t.
What surface finishes work on 7204?
Takes sulphuric and hard anodize well (slightly grey cast), plus chromate/chrome-free conversion coating and powder coat; avoid finishing sequences that leave sustained short-transverse tensile stress.
7204 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 |
|---|---|---|
| Siimpurity limit | ≤ 0.35 | — |
| Feimpurity limit | ≤ 0.4 | — |
| Cukept low for weldability/corrosion | ≤ 0.2 | 0.1 |
| Mn | 0.2 – 0.7 | 0.4 |
| Mg | 1 – 1.8 | 1.4 |
| Cr | 0.06 – 0.2 | 0.12 |
| Zn | 4 – 5 | 4.5 |
| Zrgrain-structure control | 0.08 – 0.2 | 0.13 |
| Tigrain refiner | 0.01 – 0.06 | 0.03 |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
7204-T73 — frequently asked
What is 7204-T73 used for?
7204-T73 is typically used for welded structural extrusions, general engineering components, transport and trailer frames, welded machine frames and bases, forged structural fittings and mast and boom sections. In short: best-weldable 7000-series alloy; moderate strength, good corrosion; recovers strength after welding.
What is the yield strength of 7204-T73?
7204-T73 has a typical yield strength of 265 MPa (38.4 ksi) and a tensile strength of 320 MPa (46.4 ksi) — stronger than 69% of aluminum grades. Strength varies by condition: see the 7 listed tempers.
Is 7204-T73 easy to machine?
Reasonably — machinability is rated good (56/100, worse than 55% of aluminum grades). Machines cleanly in T5/T6 with sharp polished-flute carbide tooling, high speed and generous coolant; annealed stock is gummy and gives poor finish.
Can 7204-T73 be welded?
Yes — weldability is rated very good (82/100). One of the best-weldable 7000-series alloys — MIG/TIG with 5356 or 5183 filler; the HAZ naturally re-ages to about 75–85 % of parent strength in 30–90 days, and a 24 h/120 °C post-weld age restores more.
What surface finishes work on 7204-T73?
Takes sulphuric and hard anodize well (slightly grey cast), plus chromate/chrome-free conversion coating and powder coat; avoid finishing sequences that leave sustained short-transverse tensile stress.
Can 7204-T73 be formed, bent or molded?
Form, bend and stretch in O or freshly quenched T4 (refrigerate to delay ageing); T6 sections crack at tight radii and should be bent to at least 4–6 t.
What is the maximum service temperature of 7204-T73?
7204-T73 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 7204-T6 and 7204-O?
T6 is the default condition — default structural condition: peak strength for welded frames, beams and forged fittings. O: softest condition, used for severe forming, deep bending or straightening before heat treatment. Yield strength is 300 MPa in T6 versus 90 MPa in O.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (Al-Zn-Mg SCC behaviour) — ASM International (2005)
- EN 755-2 Aluminium and aluminium alloys — Extruded rod/bar, tube and profiles: mechanical properties (7020 analogue) — CEN (2016)
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.