Stainless Steel CK3MCuN
ASTM CK3MCuN · UNS J93254 · EN 1.4593
CK3MCuN is a super-austenitic cast stainless steel with high molybdenum plus copper and nitrogen additions, the casting equivalent of 254SMO (UNS J93254, 1.4593, ASTM A995 Gr 5A, A351/A743/A744).
Reference datasheet — CK3MCuN 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 SA condition
CK3MCuN tempers and conditions
CK3MCuN is supplied in 3 conditions, soft to hard. SA is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefault Solution annealed 1150–1205 °C, water quenched | The only standard delivery condition for CK3MCuN castings: full solution anneal and rapid quench per ASTM A351/A743 to dissolve sigma/chi and restore corrosion resistance. | 295 | 585 | 45 | 175 HB | — |
hot isostatically pressed then solution annealed | Choose for pressure-retaining or radiographed parts (pump casings, valve bodies) where shrinkage porosity must be closed to raise ductility and impact energy. | 300 | 605 | 50 | 175 HB | 2 % IACS |
Centrifugally cast, solution annealed | Pick for cylindrical products — pipe, sleeves, liners — where the finer, denser centrifugal structure gives slightly higher strength and better soundness than static castings. | 315 | 620 | 42 | 185 HB | 2 % IACS |
Supply forms, finishes and certifications
Ways CK3MCuN is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
A744 | Solution annealed, severe corrosive service acceptance | Certification |
What is CK3MCuN?
CK3MCuN is a super-austenitic cast stainless steel with high molybdenum plus copper and nitrogen additions, the casting equivalent of 254SMO (UNS J93254, 1.4593, ASTM A995 Gr 5A, A351/A743/A744). Engineers select it for chloride pitting and crevice corrosion resistance in seawater and process brines; solution-annealed castings give 295 MPa yield, 585 MPa tensile, 45 % elongation and about 175 HB (88 HRB). Cost and machining difficulty are high, service is limited to about 400 °C, and welds need over-alloyed nickel-base filler to preserve pitting resistance. Cast duplex stainless is the lower-cost alternative where chloride demands are less severe. CK3MCuN has a density of 8 g/cm³ (0.289 lb/in³), heavier than 92% of stainless steel grades. It melts at 1,320°C (2,408 °F). CK3MCuN has a yield strength of 295 MPa (42.8 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 70% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 195 GPa (28.3 Msi).
What is CK3MCuN used for?
- Seawater pump and valve castings
- Offshore and desalination equipment
- Flue gas desulfurization components
Advantages
- Good corrosion resistance — 88/100, better than 97% of stainless steel grades
- Ductile — tolerates forming and impact — 45%, better than 76% of stainless steel grades
Limitations
- Difficult to machine — 25/100, worse than 88% of stainless steel grades
- Limited service temperature — 400°C (752 °F), worse than 78% of stainless steel grades
- Low electrical conductivity — 2 % IACS, worse than 77% of stainless steel grades
CK3MCuN properties
Typical room-temperature values for CK3MCuN-SA; bars are the position among stainless steel grades.
Physical3
CK3MCuN has a density of 8 g/cm³ (0.289 lb/in³), heavier than 92% of stainless steel grades. It melts at 1,320°C (2,408 °F).
Mechanical14
CK3MCuN has a yield strength of 295 MPa (42.8 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 70% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
CK3MCuN is rated for continuous service to 400°C (752 °F). It conducts heat at 13.5 W/m·K (7.8 BTU/hr·ft·°F), worse than 83% of stainless steel grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
CK3MCuN conducts electricity at 2 % IACS, worse than 77% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), better than 97% of stainless steel grades.
Sustainability4
Producing a kilogram of CK3MCuN takes about 78 MJ of energy and emits 5.2 kg of CO₂ — more than 87% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
CK3MCuN's machinability is poor (25/100, worse than 88% of stainless steel grades); weldability very good (70/100); formability fair (40/100).
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 stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. CK3MCuN is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CK3MCuN
Is CK3MCuN easy to machine?
Difficult: heavily work-hardening — use rigid setups, sharp positive-rake carbide, low speed (25–45 m/min) with heavy constant feed and flood coolant, never dwell.
Can CK3MCuN be welded?
GTAW/GMAW with over-alloyed Ni-base filler (ERNiCrMo-3/ERNiCrMo-4); keep interpass below ~150 °C, low heat input, no preheat; re-solution anneal major repairs to restore PREN.
Can CK3MCuN be formed, bent or molded?
Wide freezing range demands generous risering and chills; pour hot with low nitrogen loss, and always solution anneal + water quench to dissolve sigma/chi phases.
CK3MCuN 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 to avoid sensitization | ≤ 0.03 | 0.02 |
| Mn | ≤ 1.2 | 0.8 |
| Si | ≤ 1 | 0.6 |
| P | ≤ 0.05 | 0.02 |
| S | ≤ 0.01 | 0.01 |
| Cr | 19.5 – 20.5 | 20 |
| Ni | 17.5 – 19.5 | 18.5 |
| Mo | 6 – 7 | 6.5 |
| Cu | 0.5 – 1 | 0.7 |
| N | 0.18 – 0.24 | 0.21 |
| Fe | balance |
What surface finishes work on CK3MCuN?
Pickle and passivate (HNO3-HF) after heat treatment or grinding to remove scale; the single-phase austenite polishes and electropolishes well, no coating normally required.
Surface treatments FabDigit runs on stainless steel 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).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel CK3MCuN in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- J93254
- ASTM
- A995 Gr 5A
- EN / DIN / Werkstoff-Nr.
- 1.4593
- Also called
- Cast 254SMO
How much does CK3MCuN cost?
CK3MCuN is a high-cost stainless steel ($$$$), pricier than about 78% 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.
CK3MCuN — frequently asked
What is CK3MCuN used for?
CK3MCuN is typically used for seawater pump and valve castings, offshore and desalination equipment and flue gas desulfurization components. In short: best chloride resistance here; cast 254SMO equivalent; seawater-grade super austenitic.
What is the yield strength of CK3MCuN?
CK3MCuN has a typical yield strength of 295 MPa (42.8 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 70% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is CK3MCuN easy to machine?
Not especially — machinability is rated poor (25/100, worse than 88% of stainless steel grades). Difficult: heavily work-hardening — use rigid setups, sharp positive-rake carbide, low speed (25–45 m/min) with heavy constant feed and flood coolant, never dwell.
Can CK3MCuN be welded?
Yes — weldability is rated very good (70/100). GTAW/GMAW with over-alloyed Ni-base filler (ERNiCrMo-3/ERNiCrMo-4); keep interpass below ~150 °C, low heat input, no preheat; re-solution anneal major repairs to restore PREN.
What surface finishes work on CK3MCuN?
Pickle and passivate (HNO3-HF) after heat treatment or grinding to remove scale; the single-phase austenite polishes and electropolishes well, no coating normally required.
Can CK3MCuN be formed, bent or molded?
Wide freezing range demands generous risering and chills; pour hot with low nitrogen loss, and always solution anneal + water quench to dissolve sigma/chi phases.
What is the maximum service temperature of CK3MCuN?
CK3MCuN is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CK3MCuN-SA and CK3MCuN CENT-SA?
SA is the default condition — the only standard delivery condition for CK3MCuN castings: full solution anneal and rapid quench per ASTM A351/A743 to dissolve sigma/chi and restore corrosion resistance. CENT-SA: pick for cylindrical products — pipe, sleeves, liners — where the finer, denser centrifugal structure gives slightly higher strength and better soundness than static castings. Yield strength is 295 MPa in SA versus 315 MPa in CENT-SA.
How much does CK3MCuN cost?
CK3MCuN is a high-cost stainless steel ($$$$), pricier than about 78% 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
- ASTM A351/A351M Castings, Austenitic, for Pressure-Containing Parts — ASTM International (2023)
- ASTM A743/A743M and A744/A744M Corrosion-Resistant Iron-Chromium-Nickel Castings — ASTM International (2021)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- 254 SMO (UNS S31254) alloy datasheet — Outokumpu (2022)
- Steel Castings Handbook, Supplement 8 — High Alloy Data Sheets, Corrosion Series — Steel Founders' Society of America (2004)
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.