Stainless Steel CD4MCu
ASTM CD4MCu · UNS J93370 · EN 1.4517, GX2CrNiMoCuN25-6-3-3
A widely used cast duplex stainless alloy containing copper for improved erosion-corrosion and sulfuric acid resistance, offering higher strength than austenitic cast grades for demanding pump and valve service.
Reference datasheet — CD4MCu 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
CD4MCu tempers and conditions
CD4MCu is supplied in 6 conditions, soft to hard. SA is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Foundry raw state only — brittle intermetallics and unbalanced phase ratio; must be solution treated before service. | 520 | 640 | 8 | 25 HRC | 2.2 % IACS |
SADefault Solution annealed ~1120 °C, water quenched | Standard supply condition for all pressure-retaining and corrosion service castings. | 550 | 745 | 25 | 21 HRC | — |
SA, nitrogen-alloyed CD4MCuN | Choose when higher ductility/toughness and better phase-balance control are required; N addition stabilises austenite. | 555 | 760 | 30 | 22 HRC | 2.2 % IACS |
HIP + solution annealed and water quenched | Specify for thick, fatigue- or leak-critical castings where internal microporosity must be closed. | 560 | 770 | 30 | 21 HRC | 2.2 % IACS |
Centrifugally cast tube/ring, solution annealed | Use for cylindrical pump liners, sleeves and rings where a denser, more uniform wall structure is wanted. | 565 | 770 | 28 | 22 HRC | 2.2 % IACS |
SA, high-strength nitrogen grade | Higher-strength N-bearing version of the 25Cr-5Ni-2Mo-3Cu family for highly loaded pump and valve parts. | 580 | 790 | 26 | 23 HRC | 2.1 % IACS |
What is CD4MCu?
A widely used cast duplex stainless alloy containing copper for improved erosion-corrosion and sulfuric acid resistance, offering higher strength than austenitic cast grades for demanding pump and valve service. CD4MCu has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F). CD4MCu has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 745 MPa (108 ksi) — stronger than 83% of stainless steel grades. Elongation at break is 25% and the elastic modulus is 200 GPa (29 Msi).
What is CD4MCu used for?
- slurry pumps
- valve trim and bodies
- phosphoric and sulfuric acid handling equipment
- marine pump casings
Advantages
- High strength — 550 MPa (79.8 ksi), better than 83% of stainless steel grades
Limitations
- Limited service temperature — 280°C (536 °F), worse than 96% of stainless steel grades
- Limited formability — 20/100, worse than 86% of stainless steel grades
CD4MCu properties
Typical room-temperature values for CD4MCu-SA; bars are the position among stainless steel grades.
Physical3
CD4MCu has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
CD4MCu has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 745 MPa (108 ksi) — stronger than 83% of stainless steel grades. Elongation at break is 25% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
CD4MCu is rated for continuous service to 280°C (536 °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 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
CD4MCu conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), better than 73% of stainless steel grades.
Sustainability4
Producing a kilogram of CD4MCu takes about 53 MJ of energy and emits 4.6 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 75%.
Manufacturability8
CD4MCu's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability good (60/100); 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. CD4MCu is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CD4MCu
Is CD4MCu easy to machine?
Work-hardening and abrasive — use rigid setups, positive-rake carbide, ~60–90 m/min surface speed, heavy constant feed and copious coolant; avoid dwelling.
Can CD4MCu be welded?
Weld with over-alloyed duplex filler (E/ER2553 or 25.10.4L) at controlled 0.5–2.5 kJ/mm heat input and interpass <150 °C; major repairs should be re-solution annealed and water quenched.
Can CD4MCu be formed, bent or molded?
Supplied as sand, investment or centrifugal castings; solution treat 1050–1120 °C followed by rapid water quench to dissolve sigma and balance ferrite/austenite.
CD4MCu 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 |
|---|---|---|
| CGrade 1A max | ≤ 0.04 | 0.03 |
| Mn | ≤ 1 | 0.7 |
| Si | ≤ 1 | 0.8 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Cr | 24.5 – 26.5 | 25.5 |
| Ni | 4.75 – 6 | 5.4 |
| Mo | 1.75 – 2.25 | 2 |
| Cu | 2.75 – 3.25 | 3 |
| Nnot specified for Gr 1A; 0.10–0.25 % for the CD4MCuN variants (Gr 1B/1C) | — | |
| Fe | balance |
What surface finishes work on CD4MCu?
Grit blast, pickle and passivate (nitric or citric acid) after heat treatment; electropolishing improves pitting resistance — no anodizing, and avoid iron contamination from carbon-steel tooling.
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 CD4MCu in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does CD4MCu cost?
CD4MCu 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.
CD4MCu — frequently asked
What is CD4MCu used for?
CD4MCu is typically used for slurry pumps, valve trim and bodies, phosphoric and sulfuric acid handling equipment and marine pump casings. In short: cu-bearing cast duplex; strong erosion-corrosion resistance; higher strength than cast austenitics.
What is the yield strength of CD4MCu?
CD4MCu has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 745 MPa (108 ksi) — stronger than 83% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is CD4MCu easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Work-hardening and abrasive — use rigid setups, positive-rake carbide, ~60–90 m/min surface speed, heavy constant feed and copious coolant; avoid dwelling.
Can CD4MCu be welded?
Yes — weldability is rated good (60/100). Weld with over-alloyed duplex filler (E/ER2553 or 25.10.4L) at controlled 0.5–2.5 kJ/mm heat input and interpass <150 °C; major repairs should be re-solution annealed and water quenched.
What surface finishes work on CD4MCu?
Grit blast, pickle and passivate (nitric or citric acid) after heat treatment; electropolishing improves pitting resistance — no anodizing, and avoid iron contamination from carbon-steel tooling.
Can CD4MCu be formed, bent or molded?
Supplied as sand, investment or centrifugal castings; solution treat 1050–1120 °C followed by rapid water quench to dissolve sigma and balance ferrite/austenite.
What is the maximum service temperature of CD4MCu?
CD4MCu is rated for continuous use to about 280°C (536 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CD4MCu-SA and CD4MCu-AC?
SA is the default condition — standard supply condition for all pressure-retaining and corrosion service castings. AC: foundry raw state only — brittle intermetallics and unbalanced phase ratio; must be solution treated before service. Yield strength is 550 MPa in SA versus 520 MPa in AC.
How much does CD4MCu cost?
CD4MCu 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 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)
- EN 10283 — Corrosion resistant steel castings (1.4517 GX2CrNiMoCuN25-6-3-3) — CEN (2019)
- 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)
- GB/T 2100 / GB/T 23879 (2017)
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.