Aluminum C355.0-T7
Temper
UNS A33550
T7 = solution heat treated and overaged (stabilized)
Use where dimensional stability at elevated temperature and improved toughness matter more than peak strength.
Values for the T7 condition
Other C355.0 tempers and conditions
C355.0 is listed in 5 conditions; see the grade overview at C355.0.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Pick only for non-structural parts or as the shipping state before customer heat treatment. | 90 | 165 | 2.5 | 65 HB | 36 % IACS |
T7This page Solution heat treated and overaged (stabilized) | Use where dimensional stability at elevated temperature and improved toughness matter more than peak strength. | 200 | 255 | 4.5 | 80 HB | 41 % IACS |
T6Default Solution heat treated and artificially aged | The standard stocked condition: best balance of high strength and usable ductility for structural sand and permanent-mold castings. | 207 | 275 | 4 | 85 HB | 39 % IACS |
T6 variant, underaged | Choose when maximum yield strength and hardness are needed and 2–3 % elongation is acceptable (typical aerospace permanent-mold castings). | 240 | 290 | 3 | 90 HB | 39 % IACS |
T6, heat treated by the user | Permanent-mold option (ASTM B108) for the highest hardness/strength where ductility and toughness are secondary. | 275 | 310 | 2 | 100 HB | 38 % IACS |
What is C355.0-T7?
C355.0-T7 is C355.0 in the T7 temper — use where dimensional stability at elevated temperature and improved toughness matter more than peak strength. C355.0-T7 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 255 MPa (37 ksi) — stronger than 53% of aluminum grades. Elongation at break is 4.5% and the elastic modulus is 71 GPa (10.3 Msi). C355.0-T7 has a density of 2.71 g/cm³ (0.0979 lb/in³), heavier than 51% of aluminum grades. It melts at 546°C (1,015 °F). T6 is the default condition FabDigit quotes; T7 is available on request or by drawing note.
Advantages
- High service temperature — 175°C (347 °F), better than 83% of aluminum grades
- High electrical conductivity — 41 % IACS, better than 78% of aluminum grades
- Tough — resists crack growth — 30 MPa·√m (27.3 ksi·√in), better than 76% of aluminum grades
C355.0-T7 properties
Typical room-temperature values for C355.0-T7; 21 are specific to this condition. Other listed values are C355.0 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
C355.0-T7 has a density of 2.71 g/cm³ (0.0979 lb/in³), heavier than 51% of aluminum grades. It melts at 546°C (1,015 °F).
Mechanical12
C355.0-T7 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 255 MPa (37 ksi) — stronger than 53% of aluminum grades. Elongation at break is 4.5% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
C355.0-T7 is rated for continuous service to 175°C (347 °F). It conducts heat at 155 W/m·K (89.6 BTU/hr·ft·°F), better than 71% of aluminum grades. Thermal expansion is 22.4 µm/m·K (12.4 µin/in·°F).
Electrical3
C355.0-T7 conducts electricity at 41 % IACS, better than 78% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 51% of aluminum grades.
Sustainability4
Producing a kilogram of C355.0-T7 takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 25%.
Manufacturability8
C355.0-T7's machinability is good (60/100, worse than 51% of aluminum grades); weldability good (55/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C355.0-T7
Is C355.0 easy to machine?
Machines well in T6/T61 with polished-flute carbide, high speed and flood coolant; the eutectic Si is abrasive, so use PCD for long production runs.
Can C355.0 be welded?
TIG/MIG repair with 4043 or 4145 filler is practical but the Cu content raises hot-crack sensitivity — re-solution and re-age after structural repairs.
Can C355.0 be formed, bent or molded?
Sand and permanent-mold (also investment) casting alloy with excellent fluidity and pressure tightness; needs good gating/chill practice and clean, degassed melt to reach rated properties — HIP is often used on aerospace parts.
What surface finishes work on C355.0?
Takes chromate conversion and hard anodize (grey, non-decorative), primes and paints well; shot-peen fillets for fatigue-critical castings.
C355.0 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 |
|---|---|---|
| Si | 4.5 – 5.5 | 5 |
| Cu | 1 – 1.5 | 1.25 |
| Mg | 0.4 – 0.6 | 0.5 |
| Felow-iron premium quality | ≤ 0.2 | — |
| Mn | ≤ 0.1 | — |
| Zn | ≤ 0.1 | — |
| Tigrain refiner | ≤ 0.2 | — |
| Others (each)total 0.15 max | ≤ 0.05 | — |
| Al | balance | — |
C355.0-T7 — frequently asked
What is C355.0-T7 used for?
C355.0-T7 is typically used for aircraft housings, wheels, structural brackets and gearbox cases. In short: high-strength structural casting; controlled-purity 355.0 variant; pressure-tight castings.
What is the yield strength of C355.0-T7?
C355.0-T7 has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 255 MPa (37 ksi) — stronger than 53% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is C355.0-T7 easy to machine?
Reasonably — machinability is rated good (60/100, worse than 51% of aluminum grades). Machines well in T6/T61 with polished-flute carbide, high speed and flood coolant; the eutectic Si is abrasive, so use PCD for long production runs.
Can C355.0-T7 be welded?
Yes — weldability is rated good (55/100). TIG/MIG repair with 4043 or 4145 filler is practical but the Cu content raises hot-crack sensitivity — re-solution and re-age after structural repairs.
What surface finishes work on C355.0-T7?
Takes chromate conversion and hard anodize (grey, non-decorative), primes and paints well; shot-peen fillets for fatigue-critical castings.
Can C355.0-T7 be formed, bent or molded?
Sand and permanent-mold (also investment) casting alloy with excellent fluidity and pressure tightness; needs good gating/chill practice and clean, degassed melt to reach rated properties — HIP is often used on aerospace parts.
What is the maximum service temperature of C355.0-T7?
C355.0-T7 is rated for continuous use to about 175°C (347 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C355.0-T6 and C355.0-F?
T6 is the default condition — the standard stocked condition: best balance of high strength and usable ductility for structural sand and permanent-mold castings. F: pick only for non-structural parts or as the shipping state before customer heat treatment. Yield strength is 207 MPa in T6 versus 90 MPa in F.
Sources
- Designations and Chemical Composition Limits for Aluminum Alloys in the Form of Castings and Ingot (Teal Sheets) — The Aluminum Association (2018)
- ASTM B26/B26M — Aluminum-Alloy Sand Castings — ASTM International (2018)
- ASTM B108/B108M — Aluminum-Alloy Permanent Mold Castings — ASTM International (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Aluminum: Properties and Physical Metallurgy (ed. J.E. Hatch) — ASM International (1984)
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.