Aluminum C355.0-T61
Temper
UNS A33550
T61 = t6 variant, underaged
Choose when maximum yield strength and hardness are needed and 2–3 % elongation is acceptable (typical aerospace permanent-mold castings).
Values for the T61 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 |
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 |
T61This page 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-T61?
C355.0-T61 is C355.0 in the T61 temper — choose when maximum yield strength and hardness are needed and 2–3 % elongation is acceptable (typical aerospace permanent-mold castings). C355.0-T61 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 290 MPa (42.1 ksi) — stronger than 63% of aluminum grades. Elongation at break is 3% and the elastic modulus is 71 GPa (10.3 Msi). C355.0-T61 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; T61 is available on request or by drawing note.
Limitations
- Limited formability — 10/100, worse than 80% of aluminum grades
- Limited ductility — 3%, worse than 79% of aluminum grades
C355.0-T61 properties
Typical room-temperature values for C355.0-T61; 11 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-T61 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-T61 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 290 MPa (42.1 ksi) — stronger than 63% of aluminum grades. Elongation at break is 3% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
C355.0-T61 is rated for continuous service to 150°C (302 °F). It conducts heat at 151 W/m·K (87.2 BTU/hr·ft·°F), better than 63% of aluminum grades. Thermal expansion is 22.4 µm/m·K (12.4 µin/in·°F).
Electrical3
C355.0-T61 conducts electricity at 39 % IACS, better than 65% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (48/100), worse than 58% of aluminum grades.
Sustainability4
Producing a kilogram of C355.0-T61 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-T61's machinability is good (65/100, better than 62% of aluminum grades); weldability good (55/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C355.0-T61
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-T61 — frequently asked
What is C355.0-T61 used for?
C355.0-T61 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-T61?
C355.0-T61 has a typical yield strength of 240 MPa (34.8 ksi) and a tensile strength of 290 MPa (42.1 ksi) — stronger than 63% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is C355.0-T61 easy to machine?
Reasonably — machinability is rated good (65/100, better than 62% 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-T61 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-T61?
Takes chromate conversion and hard anodize (grey, non-decorative), primes and paints well; shot-peen fillets for fatigue-critical castings.
Can C355.0-T61 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-T61?
C355.0-T61 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 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.