Stainless Steel 1.4659
EN 1.4659 · UNS S31266 · also Uranus SB8
1.4659 (X1CrNiMoCuNW24-22-6, S31266, Uranus SB8) is a tungsten-, copper- and nitrogen-alloyed superaustenitic stainless steel whose high molybdenum content gives pitting, crevice and general corrosion resistance in aggressive chloride and acidic media.
Reference datasheet — 1.4659 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
1.4659 tempers and conditions
1.4659 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 |
|---|---|---|---|---|---|---|
forged then solution annealed (flanges, valve bodies, fittings) | Heavy forged sections per ASTM A182-type practice for valves, flanges and pump parts. | 450 | 800 | 45 | 205 HB | 1.7 % IACS |
SADefault Solution annealed | Standard supply condition for plate, sheet, bar and tube; maximum corrosion resistance and toughness. | 460 | 820 | 48 | 210 HB | — |
Cold drawn | Bar stock for shafts, fasteners and valve trim where tighter tolerance and higher yield strength are needed. | 650 | 930 | 30 | 25 HRC | 1.7 % IACS |
Supply forms, finishes and certifications
Ways 1.4659 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
TUBE-SA | Tube SA | Supply form |
CRA-2B | CRA 2B | Surface finish |
HRAP | Hot-rolled, solution annealed and pickled plate | Surface finish |
What is 1.4659?
1.4659 (X1CrNiMoCuNW24-22-6, S31266, Uranus SB8) is a tungsten-, copper- and nitrogen-alloyed superaustenitic stainless steel whose high molybdenum content gives pitting, crevice and general corrosion resistance in aggressive chloride and acidic media. Engineers select it where a 460 MPa yield, 820 MPa tensile and 48 % elongation must be combined with a 93/100 corrosion rating; it is stocked as solution-annealed plate, hot-rolled and cold-rolled sheet (HRAP, CRA-2B), cold-drawn bar, forgings and tube. Machinability is low (score 18), cost approaches nickel-base alloys and stock availability is limited, with service capped at 400 °C. Where duty is less severe, 1.4547 (254 SMO) is the nearest lower-alloy alternative. 1.4659 has a density of 8.05 g/cm³ (0.291 lb/in³), heavier than 98% of stainless steel grades. It melts at 1,330°C (2,426 °F). 1.4659 has a yield strength of 460 MPa (66.7 ksi) and a tensile strength of 820 MPa (119 ksi) — stronger than 73% of stainless steel grades. Elongation at break is 48% and the elastic modulus is 195 GPa (28.3 Msi).
What is 1.4659 used for?
- FGD scrubber components
- seawater and brine handling
- chemical process vessels
- marine and offshore piping
Advantages
- Good corrosion resistance — 93/100, better than 100% of stainless steel grades
- Polishes to a fine finish — 80/100, better than 89% of stainless steel grades
- Ductile — tolerates forming and impact — 48%, better than 85% of stainless steel grades
Limitations
- Poor heat conductor — 11 W/m·K (6.36 BTU/hr·ft·°F), worse than 99% of stainless steel grades
- Difficult to machine — 18/100, worse than 99% of stainless steel grades
- Low electrical conductivity — 1.7 % IACS, worse than 93% of stainless steel grades
- High embodied carbon — 6.2 kg CO₂/kg, worse than 90% of stainless steel grades
- Limited service temperature — 400°C (752 °F), worse than 78% of stainless steel grades
1.4659 properties
Typical room-temperature values for 1.4659-SA; bars are the position among stainless steel grades.
Physical3
1.4659 has a density of 8.05 g/cm³ (0.291 lb/in³), heavier than 98% of stainless steel grades. It melts at 1,330°C (2,426 °F).
Mechanical14
1.4659 has a yield strength of 460 MPa (66.7 ksi) and a tensile strength of 820 MPa (119 ksi) — stronger than 73% of stainless steel grades. Elongation at break is 48% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
1.4659 is rated for continuous service to 400°C (752 °F). It conducts heat at 11 W/m·K (6.36 BTU/hr·ft·°F), worse than 99% of stainless steel grades. Thermal expansion is 14.5 µm/m·K (8.06 µin/in·°F).
Electrical3
1.4659 conducts electricity at 1.7 % IACS, worse than 93% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is excellent (93/100), better than 100% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4659 takes about 85 MJ of energy and emits 6.2 kg of CO₂ — more than 92% of stainless steel grades. Typical recycled content is 40%.
Manufacturability6
1.4659's machinability is poor (18/100, worse than 99% of stainless steel grades); weldability good (65/100); formability good (55/100).
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. 1.4659 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 1.4659
Is 1.4659 easy to machine?
Treat as a Ni-base alloy: rigid setups, positive-rake coated carbide, heavy positive feed to cut under the work-hardened layer, low speeds (~20–40 m/min) and copious high-pressure coolant.
Can 1.4659 be welded?
GTAW/GMAW/SMAW with overalloyed Ni-base filler (ERNiCrMo-3/-13 or ERNiCrMo-14), low heat input, interpass < 100 °C, no preheat and no PWHT; back-purge with Ar or Ar+N₂ to preserve corrosion resistance.
Can 1.4659 be formed, bent or molded?
Cold forms readily but with ~2× the force of 304 and strong springback; hot work 1100–1200 °C followed by mandatory solution anneal and water quench.
1.4659 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 for intergranular resistance | ≤ 0.03 | 0.02 |
| Si | ≤ 0.8 | 0.3 |
| Mnraises N solubility | 2 – 4 | 3 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.02 | 0 |
| Cr | 23 – 25 | 24 |
| Ni | 21 – 24 | 22 |
| Mo | 5 – 7 | 6 |
| Cuimproves reducing-acid resistance | 1 – 2.5 | 1.5 |
| Wboosts pitting/crevice resistance | 1.5 – 2.5 | 2 |
| Naustenite stabiliser, strength and PREN | 0.35 – 0.6 | 0.45 |
| Fe | balance |
What surface finishes work on 1.4659?
Pickle (HNO₃-HF) or bead-blast plus passivation after welding to remove heat tint; electropolishing gives the best surface for high-purity or seawater duty; anodizing is not applicable.
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 1.4659 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S31266
- EN / DIN / Werkstoff-Nr.
- X1CrNiMoCuNW24-22-6
- Trade names
- Uranus SB8
How much does 1.4659 cost?
1.4659 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.
1.4659 — frequently asked
What is 1.4659 used for?
1.4659 is typically used for FGD scrubber components, seawater and brine handling, chemical process vessels and marine and offshore piping. In short: tungsten-alloyed superaustenitic; beyond 6Mo corrosion resistance; nickel-alloy behaviour, stainless base.
What is the yield strength of 1.4659?
1.4659 has a typical yield strength of 460 MPa (66.7 ksi) and a tensile strength of 820 MPa (119 ksi) — stronger than 73% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is 1.4659 easy to machine?
Not especially — machinability is rated poor (18/100, worse than 99% of stainless steel grades). Treat as a Ni-base alloy: rigid setups, positive-rake coated carbide, heavy positive feed to cut under the work-hardened layer, low speeds (~20–40 m/min) and copious high-pressure coolant.
Can 1.4659 be welded?
Yes — weldability is rated good (65/100). GTAW/GMAW/SMAW with overalloyed Ni-base filler (ERNiCrMo-3/-13 or ERNiCrMo-14), low heat input, interpass < 100 °C, no preheat and no PWHT; back-purge with Ar or Ar+N₂ to preserve corrosion resistance.
What surface finishes work on 1.4659?
Pickle (HNO₃-HF) or bead-blast plus passivation after welding to remove heat tint; electropolishing gives the best surface for high-purity or seawater duty; anodizing is not applicable.
Can 1.4659 be formed, bent or molded?
Cold forms readily but with ~2× the force of 304 and strong springback; hot work 1100–1200 °C followed by mandatory solution anneal and water quench.
What is the maximum service temperature of 1.4659?
1.4659 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 1.4659-SA and 1.4659-CD?
SA is the default condition — standard supply condition for plate, sheet, bar and tube; maximum corrosion resistance and toughness. CD: bar stock for shafts, fasteners and valve trim where tighter tolerance and higher yield strength are needed. Yield strength is 460 MPa in SA versus 650 MPa in CD.
How much does 1.4659 cost?
1.4659 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 A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet and Strip (UNS S31266) — ASTM International (2023)
- EN 10088-2 / EN 10028-7 — Stainless steels, grade 1.4659 (X1CrNiMoCuNW24-22-6) — CEN (2017)
- UR SB8 / B66 superaustenitic stainless steel datasheet — Industeel (ArcelorMittal) (2021)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
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.