Stainless Steel CD3MCuN-AC (Spheroidize annealed)
Heat-treated state
ASTM CD3MCuN · UNS J93373
Reference only: the as-cast structure holds sigma phase and nitrides that cut elongation to 12 % and corrosion resistance, and the standard does not allow it as a delivery condition.
Values for the AC condition
Other CD3MCuN tempers and conditions
CD3MCuN is listed in 4 conditions; see the grade overview at CD3MCuN.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ACThis page Spheroidize annealed | Reference only: the as-cast structure holds sigma phase and nitrides that cut elongation to 12 % and corrosion resistance, and the standard does not allow it as a delivery condition. | 540 | 700 | 12 | 24 HRC | 2.2 % IACS |
SADefault Solution annealed ≥1120 °C, water quenched | Use the standard supply condition, solution annealed at ≥1120 °C and water quenched, to dissolve sigma phase and balance the ferrite/austenite ratio for 550 MPa yield and full corrosion resistance. | 550 | 740 | 32 | 21 HRC | 2.2 % IACS |
Hot isostatically pressed then solution annealed and quenched | Choose hot isostatic pressing before solution annealing and quenching for critical high-pressure seawater pump casings and valve bodies that must be free of shrinkage porosity; elongation reaches 35 %. | 560 | 770 | 35 | 22 HRC | 2.2 % IACS |
Centrifugally cast, solution annealed | Pick centrifugally cast and solution annealed pipe or ring stock for a denser structure and slightly higher properties, 570 MPa yield and 780 MPa tensile, than equivalent sand castings. | 570 | 780 | 30 | 22 HRC | 2.2 % IACS |
What is CD3MCuN-AC?
CD3MCuN-AC is CD3MCuN heat treated to AC — reference only: the as-cast structure holds sigma phase and nitrides that cut elongation to 12 % and corrosion resistance, and the standard does not allow it as a delivery condition. CD3MCuN-AC has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 82% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi). CD3MCuN-AC has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,380°C (2,516 °F). SA is the default condition FabDigit quotes; AC is available on request or by drawing note.
Advantages
- Low embodied carbon — 3.6 kg CO₂/kg, better than 83% of stainless steel grades
- High strength — 540 MPa (78.3 ksi), better than 82% of stainless steel grades
Limitations
- Limited service temperature — 250°C (482 °F), worse than 99% of stainless steel grades
- Limited ductility — 12%, worse than 95% of stainless steel grades
- Low fracture toughness — 50 MPa·√m (45.5 ksi·√in), worse than 92% of stainless steel grades
- Limited formability — 15/100, worse than 91% of stainless steel grades
- Difficult to machine — 25/100, worse than 88% of stainless steel grades
CD3MCuN-AC properties
Typical room-temperature values for CD3MCuN-AC; 22 are specific to this condition. Other listed values are CD3MCuN reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
CD3MCuN-AC has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,380°C (2,516 °F).
Mechanical17
CD3MCuN-AC has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 82% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
CD3MCuN-AC is rated for continuous service to 250°C (482 °F). It conducts heat at 16 W/m·K (9.24 BTU/hr·ft·°F), better than 58% of stainless steel grades. Thermal expansion is 12.8 µm/m·K (7.11 µin/in·°F).
Electrical3
CD3MCuN-AC conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 71% of stainless steel grades.
Sustainability4
Producing a kilogram of CD3MCuN-AC takes about 47 MJ of energy and emits 3.6 kg of CO₂ — less than 87% of stainless steel grades. Typical recycled content is 70%.
Manufacturability8
CD3MCuN-AC's machinability is poor (25/100, worse than 88% of stainless steel grades); weldability fair (48/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CD3MCuN-AC
Is CD3MCuN easy to machine?
Work-hardens strongly, so use rigid clamping, sharp coated carbide tooling, low speed with heavy feed and ample coolant. Avoid light rubbing cuts that glaze the surface.
Can CD3MCuN be welded?
Weldability is better than CD4MCu: use 25Cr super-duplex or higher-nickel filler such as ER2594/E2595, hold interpass temperature ≤150 °C and heat input 0.5–2.5 kJ/mm. Re-solution anneal and water quench critical parts after welding.
Can CD3MCuN be formed, bent or molded?
Sand, investment and centrifugal casting are all suitable. The relatively wide solidification range calls for good feeding and riser design, and castings must be solution treated at ≥1120 °C and water quenched.
What surface finishes work on CD3MCuN?
Pickling plus nitric passivation or electropolishing gives the best pitting resistance. Mechanical polishing is possible; anodizing does not apply.
CD3MCuN 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 |
|---|---|---|
| Clow carbon, improves weldability and toughness | ≤ 0.03 | 0.02 |
| Mn | ≤ 1.2 | 0.8 |
| Si | ≤ 1.1 | 0.8 |
| P | ≤ 0.03 | — |
| SA995 often imposes a tighter limit | ≤ 0.03 | — |
| Cr | 24 – 26.7 | 25.5 |
| Ni | 5.6 – 6.7 | 6.1 |
| Mo | 2.9 – 3.8 | 3.3 |
| Cuimproves resistance to sulfuric and phosphoric acids | 1.4 – 1.9 | 1.6 |
| Nstabilizes austenite, raises pitting resistance | 0.22 – 0.33 | 0.27 |
| Fe | balance | — |
CD3MCuN-AC — frequently asked
What is CD3MCuN-AC used for?
CD3MCuN-AC is typically used for pump housings, valve bodies, marine hardware and chemical processing equipment. In short: most weldable cast duplex; low-carbon copper-bearing duplex; good as-cast toughness.
What is the yield strength of CD3MCuN-AC?
CD3MCuN-AC has a typical yield strength of 540 MPa (78.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 82% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is CD3MCuN-AC easy to machine?
Not especially — machinability is rated poor (25/100, worse than 88% of stainless steel grades). Work-hardens strongly, so use rigid clamping, sharp coated carbide tooling, low speed with heavy feed and ample coolant. Avoid light rubbing cuts that glaze the surface.
Can CD3MCuN-AC be welded?
With care — weldability is rated fair (48/100). Weldability is better than CD4MCu: use 25Cr super-duplex or higher-nickel filler such as ER2594/E2595, hold interpass temperature ≤150 °C and heat input 0.5–2.5 kJ/mm. Re-solution anneal and water quench critical parts after welding.
What surface finishes work on CD3MCuN-AC?
Pickling plus nitric passivation or electropolishing gives the best pitting resistance. Mechanical polishing is possible; anodizing does not apply.
Can CD3MCuN-AC be formed, bent or molded?
Sand, investment and centrifugal casting are all suitable. The relatively wide solidification range calls for good feeding and riser design, and castings must be solution treated at ≥1120 °C and water quenched.
What is the maximum service temperature of CD3MCuN-AC?
CD3MCuN-AC is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CD3MCuN-SA and CD3MCuN CF-SA?
SA is the default condition — use the standard supply condition, solution annealed at ≥1120 °C and water quenched, to dissolve sigma phase and balance the ferrite/austenite ratio for 550 MPa yield and full corrosion resistance. CF-SA: pick centrifugally cast and solution annealed pipe or ring stock for a denser structure and slightly higher properties, 570 MPa yield and 780 MPa tensile, than equivalent sand castings. Yield strength is 550 MPa in SA versus 570 MPa in CF-SA.
Sources
- ASTM A890/A890M — Castings, Iron-Chromium-Nickel-Molybdenum Corrosion-Resistant, Duplex — ASTM International (2023)
- ASTM A995/A995M — Castings, Austenitic-Ferritic (Duplex) Stainless Steel, for Pressure-Containing Parts — ASTM International (2020)
- ASM Handbook Vol.1: Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13B: Corrosion — Materials — ASM International (2005)
- UNS J93373 alloy data (SAE/ASTM Metals & Alloys in the Unified Numbering System) — SAE International (2017)
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.