Aluminum C355.0
UNS A33550
C355.0 is a high-integrity Al-Si5Cu1.3Mg casting alloy in the ANSI/AA 3xx.x family, with tighter impurity control than 355.0 and heat treated to T6, T61, T62 or T7 for structural service.
Reference datasheet — C355.0 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the T6 condition
C355.0 tempers and conditions
C355.0 is supplied in 5 conditions, soft to hard. T6 is the default FabDigit quotes; the values on this page are for it.
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 |
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?
C355.0 is a high-integrity Al-Si5Cu1.3Mg casting alloy in the ANSI/AA 3xx.x family, with tighter impurity control than 355.0 and heat treated to T6, T61, T62 or T7 for structural service. In the default T6-class condition it gives 275 MPa tensile, 207 MPa yield, 4% elongation, 85 HB and a 71 GPa modulus with 151 W/m·K conductivity, poured as sand, permanent-mold and investment castings for aerospace and automotive housings. The copper content lowers corrosion resistance (score 48) and raises hot-cracking risk in repair welds, and service is capped near 150 °C; A356.0-T6 is preferred when corrosion resistance outweighs strength. C355.0 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). C355.0 has a yield strength of 207 MPa (30 ksi) and a tensile strength of 275 MPa (39.9 ksi) — stronger than 55% of aluminum grades. Elongation at break is 4% and the elastic modulus is 71 GPa (10.3 Msi).
What is C355.0 used for?
- aircraft housings
- wheels
- structural brackets
- gearbox cases
Limitations
- Limited formability — 10/100, worse than 80% of aluminum grades
C355.0 properties
Typical room-temperature values for C355.0-T6; bars are the position among aluminum grades.
Physical3
C355.0 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 has a yield strength of 207 MPa (30 ksi) and a tensile strength of 275 MPa (39.9 ksi) — stronger than 55% of aluminum grades. Elongation at break is 4% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
C355.0 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 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 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's machinability is good (62/100, better than 55% of aluminum grades); weldability good (55/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the aluminum family
Yield strength against density for every aluminum grade FabDigit runs. C355.0 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C355.0
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.
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 |
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.
Surface treatments FabDigit runs on aluminum parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Equivalent designations
Standards and trade names that resolve to Aluminum C355.0 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- A33550
- Also called
- SC51B
How much does C355.0 cost?
C355.0 is a standard-cost aluminum ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C355.0 — frequently asked
What is C355.0 used for?
C355.0 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?
C355.0 has a typical yield strength of 207 MPa (30 ksi) and a tensile strength of 275 MPa (39.9 ksi) — stronger than 55% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is C355.0 easy to machine?
Reasonably — machinability is rated good (62/100, better than 55% 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 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?
Takes chromate conversion and hard anodize (grey, non-decorative), primes and paints well; shot-peen fillets for fatigue-critical castings.
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 is the maximum service temperature of C355.0?
C355.0 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.
How much does C355.0 cost?
C355.0 is a standard-cost aluminum ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.