Stainless Steel CD4MCuN-AC (Spheroidize annealed)
Heat-treated state
ASTM CD4MCuN · UNS J93372 · EN 1.4515
Intermediate condition after pouring; unbalanced phases and intermetallics mean it must be solution treated before any corrosion or pressure service.
Values for the AC condition
Other CD4MCuN tempers and conditions
CD4MCuN is listed in 4 conditions; see the grade overview at CD4MCuN.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ACThis page Spheroidize annealed | Intermediate condition after pouring; unbalanced phases and intermetallics mean it must be solution treated before any corrosion or pressure service. | 500 | 650 | 8 | 28 HRC | 2.2 % IACS |
SADefault Solution annealed ~1120 °C and water quenched | Standard as-supplied condition for all pressure-retaining and corrosion service; gives the balanced 50/50 ferrite-austenite structure. | 550 | 730 | 25 | 24 HRC | 2.2 % IACS |
hot isostatically pressed then solution annealed and quenched | Choose for thick-section pump casings and valve bodies where shrinkage porosity must be closed for radiography and fatigue life. | 560 | 760 | 28 | 24 HRC | 2.2 % IACS |
SA + aged ~480 °C | Occasionally used for slurry-pump wear parts where extra hardness is wanted; sacrifices impact toughness and some corrosion margin, and is outside ASTM A890/A995 supply conditions. | 700 | 860 | 10 | 34 HRC | 2.4 % IACS |
What is CD4MCuN-AC?
CD4MCuN-AC is CD4MCuN heat treated to AC — intermediate condition after pouring; unbalanced phases and intermetallics mean it must be solution treated before any corrosion or pressure service. CD4MCuN-AC has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 650 MPa (94.3 ksi) — stronger than 77% of stainless steel grades. Elongation at break is 8% and the elastic modulus is 200 GPa (29 Msi). CD4MCuN-AC has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,410°C (2,570 °F). SA is the default condition FabDigit quotes; AC is available on request or by drawing note.
Advantages
- High strength — 500 MPa (72.5 ksi), better than 77% of stainless steel grades
Limitations
- Limited ductility — 8%, worse than 99% of stainless steel grades
- Limited formability — 5/100, worse than 99% of stainless steel grades
- Low fracture toughness — 40 MPa·√m (36.4 ksi·√in), worse than 97% of stainless steel grades
- Difficult to machine — 22/100, worse than 95% of stainless steel grades
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
CD4MCuN-AC properties
Typical room-temperature values for CD4MCuN-AC; 21 are specific to this condition. Other listed values are CD4MCuN reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
CD4MCuN-AC has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,410°C (2,570 °F).
Mechanical16
CD4MCuN-AC has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 650 MPa (94.3 ksi) — stronger than 77% of stainless steel grades. Elongation at break is 8% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
CD4MCuN-AC is rated for continuous service to 300°C (572 °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 µm/m·K (6.67 µin/in·°F).
Electrical3
CD4MCuN-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 CD4MCuN-AC takes about 53 MJ of energy and emits 4.6 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 70%.
Manufacturability8
CD4MCuN-AC's machinability is poor (22/100, worse than 95% of stainless steel grades); weldability fair (35/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CD4MCuN-AC
Is CD4MCuN easy to machine?
Machine like a duplex stainless: rigid setup, 30–60 % of 304 speeds, positive-rake coated carbide, heavy constant feed to cut under the work-hardened skin, flood coolant.
Can CD4MCuN be welded?
GTAW/SMAW with 25Cr duplex (ER2553/E2553) or over-alloyed 25Cr-9Ni-4Mo filler, interpass ≤150 °C, heat input 0.5–2.0 kJ/mm; full re-solution anneal + water quench is preferred after major weld repair.
Can CD4MCuN be formed, bent or molded?
Supplied only as castings — sand, investment or centrifugal; needs generous risering (wide freezing range), 1100–1150 °C solution treatment followed by rapid water quench to avoid σ-phase.
What surface finishes work on CD4MCuN?
Passivate per ASTM A967 (nitric or citric) or pickle/electropolish after heat treatment; not anodizable — shot blast plus pickling is normal for cast surfaces.
CD4MCuN 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 | ≤ 0.04 | 0.03 |
| Mn | ≤ 1 | 0.7 |
| Si | ≤ 1 | 0.8 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Cr | 24.5 – 26.5 | 25.5 |
| Ni | 4.7 – 6 | 5.4 |
| Mo | 1.7 – 2.3 | 2 |
| Cu | 2.7 – 3.3 | 3 |
| Nnitrogen addition distinguishing CD4MCuN from CD4MCu | 0.1 – 0.25 | 0.18 |
| Fe | balance | — |
CD4MCuN-AC — frequently asked
What is CD4MCuN-AC used for?
CD4MCuN-AC is typically used for pump casings, valve bodies, wellhead components and chloride service castings. In short: copper-bearing cast duplex; tougher than CD4MCu; 550 MPa cast yield.
What is the yield strength of CD4MCuN-AC?
CD4MCuN-AC has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 650 MPa (94.3 ksi) — stronger than 77% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is CD4MCuN-AC easy to machine?
Not especially — machinability is rated poor (22/100, worse than 95% of stainless steel grades). Machine like a duplex stainless: rigid setup, 30–60 % of 304 speeds, positive-rake coated carbide, heavy constant feed to cut under the work-hardened skin, flood coolant.
Can CD4MCuN-AC be welded?
With care — weldability is rated fair (35/100). GTAW/SMAW with 25Cr duplex (ER2553/E2553) or over-alloyed 25Cr-9Ni-4Mo filler, interpass ≤150 °C, heat input 0.5–2.0 kJ/mm; full re-solution anneal + water quench is preferred after major weld repair.
What surface finishes work on CD4MCuN-AC?
Passivate per ASTM A967 (nitric or citric) or pickle/electropolish after heat treatment; not anodizable — shot blast plus pickling is normal for cast surfaces.
Can CD4MCuN-AC be formed, bent or molded?
Supplied only as castings — sand, investment or centrifugal; needs generous risering (wide freezing range), 1100–1150 °C solution treatment followed by rapid water quench to avoid σ-phase.
What is the maximum service temperature of CD4MCuN-AC?
CD4MCuN-AC is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CD4MCuN-SA and CD4MCuN SA-AGED?
SA is the default condition — standard as-supplied condition for all pressure-retaining and corrosion service; gives the balanced 50/50 ferrite-austenite structure. SA-AGED: occasionally used for slurry-pump wear parts where extra hardness is wanted; sacrifices impact toughness and some corrosion margin, and is outside ASTM A890/A995 supply conditions. Yield strength is 550 MPa in SA versus 700 MPa in SA-AGED.
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 (cast stainless) — ASM International (1990)
- Steel Castings Handbook (SFSA), 6th ed. — Steel Founders' Society of America / ASM (1995)
- UNS J93372 alloy data — SAE/ASTM Unified Numbering System (2019)
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.