Stainless Steel CD6MN
ASTM CD6MN · UNS J93371
CD6MN (ASTM A890/A995 Grade 3A, UNS J93371, 1.4468 / GX2CrNiMoN25-6-3) is a copper-free 25Cr-5Ni-2Mo-N duplex casting alloy chosen for high strength combined with chloride pitting resistance in feedwater and process equipment.
Reference datasheet — CD6MN 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
CD6MN tempers and conditions
CD6MN is supplied in 5 conditions, soft to hard. SA is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Only for non-critical wear or structural parts; sigma/nitride precipitation leaves low toughness and degraded pitting resistance. | 500 | 690 | 12 | 24 HRC | 2.2 % IACS |
Weld repaired, then re-solution annealed and quenched | Standard route for foundry-repaired castings; full re-anneal after major repairs restores phase balance in the weld and HAZ. | 515 | 710 | 28 | 21 HRC | 2.2 % IACS |
SADefault Solution annealed ≥1120 °C and water quenched | The only condition permitted for pressure-retaining service; restores 40–55 % ferrite balance and dissolves sigma/nitrides. | 520 | 720 | 32 | 21 HRC | — |
Hot isostatically pressed, then solution annealed and quenched | Choose for thick-section pump/valve castings needing closed microporosity, higher ductility and better NDE/radiographic acceptance. | 540 | 750 | 36 | 22 HRC | 2.2 % IACS |
Centrifugally cast (ASTM A872 class), solution annealed and quenched | For seamless duplex tubulars and rings; directional solidification gives cleaner, finer structure and slightly higher strength than static castings. | 550 | 760 | 30 | 23 HRC | 2.2 % IACS |
What is CD6MN?
CD6MN (ASTM A890/A995 Grade 3A, UNS J93371, 1.4468 / GX2CrNiMoN25-6-3) is a copper-free 25Cr-5Ni-2Mo-N duplex casting alloy chosen for high strength combined with chloride pitting resistance in feedwater and process equipment. Sand and centrifugal castings are supplied solution-annealed, HIP plus solution-annealed, as-cast or weld-repaired and annealed, at 520 MPa yield, 720 MPa tensile, 32 % elongation and 230 HB. Service tops out near 300 °C, the alloy is abrasive and work-hardening to machine, and shrinkage of 2.0–2.2 % demands careful feeding; CE3MN is the super-duplex upgrade for harsher chloride service. CD6MN has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,400°C (2,552 °F). CD6MN has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 79% of stainless steel grades. Elongation at break is 32% and the elastic modulus is 195 GPa (28.3 Msi).
What is CD6MN used for?
- feedwater heater components
- pump casings
- valve trim
- paper mill equipment
Advantages
- Good corrosion resistance — 76/100, better than 80% of stainless steel grades
- High strength — 520 MPa (75.4 ksi), better than 79% of stainless steel grades
Limitations
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
- Limited formability — 20/100, worse than 86% of stainless steel grades
CD6MN properties
Typical room-temperature values for CD6MN-SA; bars are the position among stainless steel grades.
Physical3
CD6MN has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical17
CD6MN has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 79% of stainless steel grades. Elongation at break is 32% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
CD6MN is rated for continuous service to 300°C (572 °F). It conducts heat at 16.5 W/m·K (9.53 BTU/hr·ft·°F), better than 70% of stainless steel grades. Thermal expansion is 12.8 µm/m·K (7.11 µin/in·°F).
Electrical3
CD6MN conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (76/100), better than 80% of stainless steel grades.
Sustainability4
Producing a kilogram of CD6MN takes about 53 MJ of energy and emits 4.5 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 80%.
Manufacturability8
CD6MN's machinability is poor (28/100, worse than 79% of stainless steel grades); weldability good (65/100); formability poor (20/100).
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. CD6MN is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CD6MN
Is CD6MN easy to machine?
Work-hardens rapidly and is abrasive — use rigid setups, sharp coated carbide, low speed (~60–90 m/min) with heavy positive feed and flood coolant; avoid dwelling.
Can CD6MN be welded?
GTAW/GMAW/SMAW with 25-9-4 (E2595/ER2594) or matching over-alloyed filler, interpass ≤150 °C, moderate heat input 0.5–2.0 kJ/mm, no preheat, no post-weld temper — re-solution anneal after major repairs.
Can CD6MN be formed, bent or molded?
Sand or centrifugal cast with generous risering; solidification range and 2.0–2.2 % shrinkage require good feeding, then mandatory ≥1120 °C solution anneal with rapid water quench.
CD6MN 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 limit carbide precipitation | ≤ 0.06 | 0.03 |
| Mn | ≤ 1 | 0.7 |
| Si | ≤ 1 | 0.8 |
| P | ≤ 0.04 | |
| S | ≤ 0.04 | |
| Cr | 24 – 27 | 25.5 |
| Ni | 4 – 6 | 5 |
| Mo | 1.75 – 2.5 | 2.1 |
| Naustenite stabiliser, raises PREN and strength | 0.15 – 0.25 | 0.2 |
| Cunot specified — copper-free variant of CD4MCu | — | |
| Fe | balance |
What surface finishes work on CD6MN?
Grit blast, pickle in HNO₃-HF and passivate per ASTM A967; polish to Ra ≤0.8 µm for maximum pitting resistance — no anodizing, and keep free of embedded carbon-steel iron.
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 CD6MN in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- J93371
- ASTM
- A890 Grade 3AA995 Grade 3A
- Similar grades
- 1.4468GX2CrNiMoN25-6-3
How much does CD6MN cost?
CD6MN is a premium-cost stainless steel ($$$), cheaper than about 51% 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.
CD6MN — frequently asked
What is CD6MN used for?
CD6MN is typically used for feedwater heater components, pump casings, valve trim and paper mill equipment. In short: copper-free 25Cr cast duplex; strong feedwater service grade; abrasive, work-hardening to machine.
What is the yield strength of CD6MN?
CD6MN has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 79% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is CD6MN easy to machine?
Not especially — machinability is rated poor (28/100, worse than 79% of stainless steel grades). Work-hardens rapidly and is abrasive — use rigid setups, sharp coated carbide, low speed (~60–90 m/min) with heavy positive feed and flood coolant; avoid dwelling.
Can CD6MN be welded?
Yes — weldability is rated good (65/100). GTAW/GMAW/SMAW with 25-9-4 (E2595/ER2594) or matching over-alloyed filler, interpass ≤150 °C, moderate heat input 0.5–2.0 kJ/mm, no preheat, no post-weld temper — re-solution anneal after major repairs.
What surface finishes work on CD6MN?
Grit blast, pickle in HNO₃-HF and passivate per ASTM A967; polish to Ra ≤0.8 µm for maximum pitting resistance — no anodizing, and keep free of embedded carbon-steel iron.
Can CD6MN be formed, bent or molded?
Sand or centrifugal cast with generous risering; solidification range and 2.0–2.2 % shrinkage require good feeding, then mandatory ≥1120 °C solution anneal with rapid water quench.
What is the maximum service temperature of CD6MN?
CD6MN 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 CD6MN-SA and CD6MN CENT-SA?
SA is the default condition — the only condition permitted for pressure-retaining service; restores 40–55 % ferrite balance and dissolves sigma/nitrides. CENT-SA: for seamless duplex tubulars and rings; directional solidification gives cleaner, finer structure and slightly higher strength than static castings. Yield strength is 520 MPa in SA versus 550 MPa in CENT-SA.
How much does CD6MN cost?
CD6MN is a premium-cost stainless steel ($$$), cheaper than about 51% 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 A995/A995M — Castings, Austenitic-Ferritic (Duplex) Stainless Steel, for Pressure-Containing Parts — ASTM International (2020)
- ASTM A890/A890M — Castings, Iron-Chromium-Nickel-Molybdenum Corrosion-Resistant, Duplex — ASTM International (2023)
- EN 10283 — Corrosion resistant steel castings (GX2CrNiMoN25-6-3, 1.4468) — CEN (2010)
- Steel Castings Handbook, Supplement 8 — High Alloy Data Sheets, Corrosion Series — Steel Founders' Society of America (2004)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Practical Guidelines for the Fabrication of Duplex Stainless Steels — IMOA (2014)
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.