Nickel Alloy CU5MCuC-AC (Spheroidize annealed)
Heat-treated state
UNS N08826, N08825 · ASTM A494 CU5MCuC
Only for non-critical or mildly corrosive service — interdendritic carbides/segregation reduce intergranular corrosion resistance.
Values for the AC condition
Other CU5MCuC tempers and conditions
CU5MCuC is listed in 4 conditions; see the grade overview at CU5MCuC.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefault Solution annealed | Standard supply condition for ASTM A494 CU5MCuC castings — maximum corrosion resistance and ductility. | 235 | 490 | 40 | 160 HB | — |
hot isostatically pressed then solution annealed | For pressure-containing or fatigue-loaded castings where shrinkage porosity must be closed. | 245 | 520 | 45 | 160 HB | 1.5 % IACS |
ACThis page Spheroidize annealed | Only for non-critical or mildly corrosive service — interdendritic carbides/segregation reduce intergranular corrosion resistance. | 250 | 470 | 25 | 170 HB | 1.5 % IACS |
solution annealed plus stabilization anneal (≈930–980 °C) | Choose when the casting will see 425–650 °C service or heavy weld repair and maximum intergranular-corrosion immunity is required. | 250 | 500 | 35 | 165 HB | 1.5 % IACS |
What is CU5MCuC-AC?
CU5MCuC-AC is CU5MCuC heat treated to AC — only for non-critical or mildly corrosive service — interdendritic carbides/segregation reduce intergranular corrosion resistance. CU5MCuC-AC has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 87% of nickel alloy grades. Elongation at break is 25% and the elastic modulus is 193 GPa (28 Msi). CU5MCuC-AC has a density of 8.1 g/cm³ (0.293 lb/in³), lighter than 80% of nickel alloy grades. It melts at 1,370°C (2,498 °F). SA is the default condition FabDigit quotes; AC is available on request or by drawing note.
Advantages
- Low embodied carbon — 6.5 kg CO₂/kg, better than 99% of nickel alloy grades
Limitations
- Low strength — 250 MPa (36.3 ksi), worse than 87% of nickel alloy grades
- Hard to polish — 60/100, worse than 84% of nickel alloy grades
- Limited service temperature — 480°C (896 °F), worse than 82% of nickel alloy grades
- Limited formability — 15/100, worse than 81% of nickel alloy grades
CU5MCuC-AC properties
Typical room-temperature values for CU5MCuC-AC; 22 are specific to this condition. Other listed values are CU5MCuC reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
CU5MCuC-AC has a density of 8.1 g/cm³ (0.293 lb/in³), lighter than 80% of nickel alloy grades. It melts at 1,370°C (2,498 °F).
Mechanical12
CU5MCuC-AC has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 87% of nickel alloy grades. Elongation at break is 25% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
CU5MCuC-AC is rated for continuous service to 480°C (896 °F). It conducts heat at 11 W/m·K (6.36 BTU/hr·ft·°F), worse than 60% of nickel alloy grades. Thermal expansion is 14 µm/m·K (7.78 µin/in·°F).
Electrical3
CU5MCuC-AC conducts electricity at 1.5 % IACS, better than 59% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), worse than 71% of nickel alloy grades.
Sustainability4
Producing a kilogram of CU5MCuC-AC takes about 95 MJ of energy and emits 6.5 kg of CO₂ — less than 97% of nickel alloy grades. Typical recycled content is 40%.
Manufacturability8
CU5MCuC-AC's machinability is poor (26/100, better than 80% of nickel alloy grades); weldability good (65/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CU5MCuC-AC
Is CU5MCuC easy to machine?
Work-hardens rapidly — use rigid setups, positive-rake carbide, heavy depth of cut, low speed (≈20–35 m/min) and flood coolant; never dwell in the cut.
Can CU5MCuC be welded?
Readily welded GTAW/SMAW with ERNiFeCr-1 (Alloy 65) or ENiCrMo-3 filler; low heat input, no preheat, interpass <150 °C, solution or stabilization anneal after major weld repair.
Can CU5MCuC be formed, bent or molded?
Sand or investment cast; long freezing range demands generous risering and chills, and pouring under argon/vacuum control to limit Ti loss and dross.
What surface finishes work on CU5MCuC?
Grit-blast and pickle (HNO₃-HF) to remove casting scale, then passivate or electropolish; not anodizable, plating is rarely needed.
CU5MCuC 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 |
|---|---|---|
| C | ≤ 0.05 | 0.03 |
| Mn | ≤ 1 | 0.7 |
| Si | ≤ 1 | 0.7 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Ni | 38 – 44 | 41 |
| Cr | 19.5 – 23.5 | 21.5 |
| Mo | 2.5 – 3.5 | 3 |
| Cuimproves sulfuric acid resistance | 1.5 – 3.5 | 2.2 |
| Ticarbide stabilizer against sensitization | 0.6 – 1.2 | 0.9 |
| Feremainder, ≈28–32 % | balance | — |
CU5MCuC-AC — frequently asked
What is CU5MCuC-AC used for?
CU5MCuC-AC is typically used for pump and valve bodies, chemical processing pumps and sulfuric acid handling equipment. In short: cast Alloy 825; sulfuric acid workhorse; most weldable cast nickel grade.
What is the yield strength of CU5MCuC-AC?
CU5MCuC-AC has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 87% of nickel alloy grades. Strength varies by condition: see the 4 listed tempers.
Is CU5MCuC-AC easy to machine?
Not especially — machinability is rated poor (26/100, better than 80% of nickel alloy grades). Work-hardens rapidly — use rigid setups, positive-rake carbide, heavy depth of cut, low speed (≈20–35 m/min) and flood coolant; never dwell in the cut.
Can CU5MCuC-AC be welded?
Yes — weldability is rated good (65/100). Readily welded GTAW/SMAW with ERNiFeCr-1 (Alloy 65) or ENiCrMo-3 filler; low heat input, no preheat, interpass <150 °C, solution or stabilization anneal after major weld repair.
What surface finishes work on CU5MCuC-AC?
Grit-blast and pickle (HNO₃-HF) to remove casting scale, then passivate or electropolish; not anodizable, plating is rarely needed.
Can CU5MCuC-AC be formed, bent or molded?
Sand or investment cast; long freezing range demands generous risering and chills, and pouring under argon/vacuum control to limit Ti loss and dross.
What is the maximum service temperature of CU5MCuC-AC?
CU5MCuC-AC is rated for continuous use to about 480°C (896 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CU5MCuC-SA and CU5MCuC-AC?
SA is the default condition — standard supply condition for ASTM A494 CU5MCuC castings — maximum corrosion resistance and ductility. AC: only for non-critical or mildly corrosive service — interdendritic carbides/segregation reduce intergranular corrosion resistance. Yield strength is 235 MPa in SA versus 250 MPa in AC.
Sources
- ASTM A494/A494M — Castings, Nickel and Nickel Alloy — ASTM International (2023)
- INCOLOY alloy 825 technical bulletin — Special Metals Corporation (2004)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
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.