Nickel Alloy CW2M-AC (Spheroidize annealed)
Heat-treated state
UNS J26455, N06200 · ASTM A494 CW2M
Rarely accepted for corrosion duty - interdendritic carbide/mu-phase network lowers ductility and localised-corrosion resistance; used only for non-wetted or trial parts.
Values for the AC condition
Other CW2M tempers and conditions
CW2M is listed in 3 conditions; see the grade overview at CW2M.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ACThis page Spheroidize annealed | Rarely accepted for corrosion duty - interdendritic carbide/mu-phase network lowers ductility and localised-corrosion resistance; used only for non-wetted or trial parts. | 285 | 480 | 22 | 14 HRC | 1.4 % IACS |
SADefault Solution annealed and rapidly quenched | Standard delivery condition for all ASTM A494 CW-2M castings; maximum corrosion resistance and ductility. | 300 | 540 | 45 | 190 HB | — |
Hot isostatically pressed then solution annealed | Choose for pressure-containing or fatigue-loaded castings where residual microporosity must be closed (pump casings, valve bodies for severe service). | 305 | 555 | 50 | 190 HB | 1.4 % IACS |
What is CW2M-AC?
CW2M-AC is CW2M heat treated to AC — rarely accepted for corrosion duty - interdendritic carbide/mu-phase network lowers ductility and localised-corrosion resistance; used only for non-wetted or trial parts. CW2M-AC has a yield strength of 285 MPa (41.3 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 81% of nickel alloy grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi). CW2M-AC has a density of 8.6 g/cm³ (0.311 lb/in³), heavier than 67% of nickel alloy grades. It melts at 1,325°C (2,417 °F). SA is the default condition FabDigit quotes; AC is available on request or by drawing note.
Limitations
- Poor heat conductor — 9.8 W/m·K (5.66 BTU/hr·ft·°F), worse than 92% of nickel alloy grades
- Low strength — 285 MPa (41.3 ksi), worse than 81% of nickel alloy grades
- Limited formability — 15/100, worse than 81% of nickel alloy grades
CW2M-AC properties
Typical room-temperature values for CW2M-AC; 23 are specific to this condition. Other listed values are CW2M reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
CW2M-AC has a density of 8.6 g/cm³ (0.311 lb/in³), heavier than 67% of nickel alloy grades. It melts at 1,325°C (2,417 °F).
Mechanical13
CW2M-AC has a yield strength of 285 MPa (41.3 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 81% of nickel alloy grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi).
Thermal5
CW2M-AC is rated for continuous service to 550°C (1,022 °F). It conducts heat at 9.8 W/m·K (5.66 BTU/hr·ft·°F), worse than 92% of nickel alloy grades. Thermal expansion is 11.2 µm/m·K (6.22 µin/in·°F).
Electrical3
CW2M-AC conducts electricity at 1.4 % IACS, worse than 80% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (82/100), better than 67% of nickel alloy grades.
Sustainability4
Producing a kilogram of CW2M-AC takes about 175 MJ of energy and emits 14 kg of CO₂ — more than 65% of nickel alloy grades. Typical recycled content is 45%.
Manufacturability8
CW2M-AC's machinability is poor (17/100, worse than 69% of nickel alloy grades); weldability good (60/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CW2M-AC
Is CW2M easy to machine?
Tough, gummy and strongly work-hardening: use rigid setups, positive-rake carbide or ceramic tooling, low speed with heavy positive feed, flood coolant and never dwell in the cut.
Can CW2M be welded?
Readily GTAW/GMAW welded with matching low-carbon Ni-Cr-Mo filler (ERNiCrMo type); keep interpass temperature low, use low heat input and no preheat; re-solution anneal heavily repaired castings.
Can CW2M be formed, bent or molded?
Supplied as sand or investment castings - design generous fillets and directional solidification with chills/risers to avoid hot tears and interdendritic shrinkage; solution treat and water quench after pouring.
What surface finishes work on CW2M?
Grit blast and pickle/passivate wetted surfaces to remove casting scale and any iron contamination; mechanical polishing improves corrosion behaviour; no anodizing or plating required.
CW2M 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 |
|---|---|---|
| Cr | 15 – 17.5 | 16 |
| Mo | 15 – 17.5 | 16 |
| Fe | ≤ 2 | 1 |
| W | ≤ 1 | 0.3 |
| Clow carbon for as-welded/as-cast corrosion resistance | ≤ 0.02 | 0.01 |
| Si | ≤ 0.8 | 0.5 |
| Mn | ≤ 1 | 0.6 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Ni | balance | — |
CW2M-AC — frequently asked
What is CW2M-AC used for?
CW2M-AC is typically used for pump casings for mixed acid service, valve trim and flue gas desulfurization components. In short: cast Alloy C-2000; widest acid range cast grade; oxidising and reducing service.
What is the yield strength of CW2M-AC?
CW2M-AC has a typical yield strength of 285 MPa (41.3 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 81% of nickel alloy grades. Strength varies by condition: see the 3 listed tempers.
Is CW2M-AC easy to machine?
Not especially — machinability is rated poor (17/100, worse than 69% of nickel alloy grades). Tough, gummy and strongly work-hardening: use rigid setups, positive-rake carbide or ceramic tooling, low speed with heavy positive feed, flood coolant and never dwell in the cut.
Can CW2M-AC be welded?
Yes — weldability is rated good (60/100). Readily GTAW/GMAW welded with matching low-carbon Ni-Cr-Mo filler (ERNiCrMo type); keep interpass temperature low, use low heat input and no preheat; re-solution anneal heavily repaired castings.
What surface finishes work on CW2M-AC?
Grit blast and pickle/passivate wetted surfaces to remove casting scale and any iron contamination; mechanical polishing improves corrosion behaviour; no anodizing or plating required.
Can CW2M-AC be formed, bent or molded?
Supplied as sand or investment castings - design generous fillets and directional solidification with chills/risers to avoid hot tears and interdendritic shrinkage; solution treat and water quench after pouring.
What is the maximum service temperature of CW2M-AC?
CW2M-AC is rated for continuous use to about 550°C (1,022 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CW2M-SA and CW2M-AC?
SA is the default condition — standard delivery condition for all ASTM A494 CW-2M castings; maximum corrosion resistance and ductility. AC: rarely accepted for corrosion duty - interdendritic carbide/mu-phase network lowers ductility and localised-corrosion resistance; used only for non-wetted or trial parts. Yield strength is 300 MPa in SA versus 285 MPa in AC.
Sources
- ASTM A494/A494M - Castings, Nickel and Nickel Alloy — ASTM International (2023)
- ASM Handbook Vol. 2 - Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Specialty Handbook: Nickel, Cobalt and Their Alloys — ASM International (2000)
- Ni-Cr-Mo corrosion-resistant alloy technical data (C-type alloys) — Alloy producers/foundries (2022)
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.