Stainless Steel S44660
UNS S44660
S44660 (Sea-Cure) is a 26Cr-3Mo-3Ni super-ferritic stainless steel developed for maximum resistance to seawater pitting and crevice corrosion, supplied mainly as annealed, bright-annealed, cold-drawn and welded-annealed tubing.
Reference datasheet — S44660 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 Annealed condition
S44660 tempers and conditions
S44660 is supplied in 2 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault mill annealed (ASTM A240 / A268 plate, sheet, tube) | Standard stocked condition for condenser/heat-exchanger tube, sheet and plate; best combination of ductility and corrosion resistance. | 500 | 620 | 27 | 190 HB | — |
Cold drawn | Use where higher strength or tighter tolerance/straightness is needed; lower ductility and residual stress, corrosion still good but stress relief preferred. | 650 | 750 | 14 | 22 HRC | 2.8 % IACS |
Supply forms, finishes and certifications
Ways S44660 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
WLD-ANN | Welded and annealed tube | Supply form |
BA | Bright Annealed | Surface finish |
What is S44660?
S44660 (Sea-Cure) is a 26Cr-3Mo-3Ni super-ferritic stainless steel developed for maximum resistance to seawater pitting and crevice corrosion, supplied mainly as annealed, bright-annealed, cold-drawn and welded-annealed tubing. Annealed properties of 500 MPa yield, 620 MPa tensile, 27 % elongation and 190 HB allow thinner tube walls than copper alloys or austenitic grades in condenser service. Formability and toughness sit below austenitics, heavy plate is rarely stocked, and welds require low heat input with inert backing. S44700 is the higher-alloy alternative. S44660 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,425°C (2,597 °F). S44660 has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 77% of stainless steel grades. Elongation at break is 27% and the elastic modulus is 200 GPa (29 Msi).
What is S44660 used for?
- marine condenser tubes
- power plant heat exchangers
- seawater piping
Advantages
- Good corrosion resistance — 88/100, better than 97% of stainless steel grades
- High electrical conductivity — 2.8 % IACS, better than 79% of stainless steel grades
- High strength — 500 MPa (72.5 ksi), better than 77% of stainless steel grades
Limitations
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
S44660 properties
Typical room-temperature values for S44660-Annealed; bars are the position among stainless steel grades.
Physical3
S44660 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,425°C (2,597 °F).
Mechanical14
S44660 has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 77% of stainless steel grades. Elongation at break is 27% and the elastic modulus is 200 GPa (29 Msi).
Thermal5
S44660 is rated for continuous service to 300°C (572 °F). It conducts heat at 15 W/m·K (8.67 BTU/hr·ft·°F), worse than 59% of stainless steel grades. Thermal expansion is 10.4 µm/m·K (5.78 µin/in·°F).
Electrical3
S44660 conducts electricity at 2.8 % IACS, better than 79% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), better than 97% of stainless steel grades.
Sustainability4
Producing a kilogram of S44660 takes about 68 MJ of energy and emits 4.8 kg of CO₂ — more than 80% of stainless steel grades. Typical recycled content is 50%.
Manufacturability7
S44660's machinability is fair (42/100, better than 79% of stainless steel grades); weldability good (55/100); 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. S44660 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S44660
Is S44660 easy to machine?
Machine like a high-Mo ferritic: rigid setups, sharp positive-rake carbide, moderate speed with heavy flood coolant; it work-hardens less than austenitics but is abrasive and tends to burr.
Can S44660 be welded?
Weld autogenously or with matching/Ni-base (e.g. ERNiCrMo) filler at low heat input and no preheat, with tight inert shielding and backing to limit grain coarsening and interstitial pickup.
Can S44660 be formed, bent or molded?
Cold forms and tube-drawns acceptably but has less stretch than austenitic grades — allow larger bend radii, expect higher springback, and stress relieve heavily worked parts (avoid 400–550 °C soaks).
S44660 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 | ≤ 0.03 | 0.02 |
| Mn | ≤ 1 | 0.4 |
| Si | ≤ 1 | 0.4 |
| P | ≤ 0.04 | |
| S | ≤ 0.03 | |
| Cr | 25 – 28 | 26 |
| Ni | 1 – 3.5 | 2.5 |
| Mo | 3 – 4 | 3.2 |
| N | ≤ 0.04 | 0.02 |
| Ti+Nbstabilizer, at least 6×(C+N) | 0.2 – 1 | 0.5 |
| Fe | balance |
What surface finishes work on S44660?
Pickle and passivate after hot work or welding; bright annealed or mechanically polished surfaces give best fouling and pitting behaviour; no anodizing or plating needed.
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 S44660 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Sea-Cure
- Also called
- SeaCure
How much does S44660 cost?
S44660 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.
S44660 — frequently asked
What is S44660 used for?
S44660 is typically used for marine condenser tubes, power plant heat exchangers and seawater piping. In short: marine condenser tube grade; super-ferritic pitting resistance; higher strength than 316L.
What is the yield strength of S44660?
S44660 has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 77% of stainless steel grades. Strength varies by condition: see the 2 listed tempers.
Is S44660 easy to machine?
Not especially — machinability is rated fair (42/100, better than 79% of stainless steel grades). Machine like a high-Mo ferritic: rigid setups, sharp positive-rake carbide, moderate speed with heavy flood coolant; it work-hardens less than austenitics but is abrasive and tends to burr.
Can S44660 be welded?
Yes — weldability is rated good (55/100). Weld autogenously or with matching/Ni-base (e.g. ERNiCrMo) filler at low heat input and no preheat, with tight inert shielding and backing to limit grain coarsening and interstitial pickup.
What surface finishes work on S44660?
Pickle and passivate after hot work or welding; bright annealed or mechanically polished surfaces give best fouling and pitting behaviour; no anodizing or plating needed.
Can S44660 be formed, bent or molded?
Cold forms and tube-drawns acceptably but has less stretch than austenitic grades — allow larger bend radii, expect higher springback, and stress relieve heavily worked parts (avoid 400–550 °C soaks).
What is the maximum service temperature of S44660?
S44660 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 S44660 Annealed and S44660-CD?
Annealed is the default condition — standard stocked condition for condenser/heat-exchanger tube, sheet and plate; best combination of ductility and corrosion resistance. CD: use where higher strength or tighter tolerance/straightness is needed; lower ductility and residual stress, corrosion still good but stress relief preferred. Yield strength is 500 MPa in Annealed versus 650 MPa in CD.
How much does S44660 cost?
S44660 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 — ASTM (2022)
- ASTM A268/A268M — Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing — ASTM (2023)
- ASTM A803/A803M — Welded Ferritic Stainless Steel Feedwater Heater Tubes — ASTM (2018)
- Sea-Cure (UNS S44660) superferritic condenser tubing data — Plymouth Tube / Crucible (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
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.