Stainless Steel S31266-AW (As-welded deposit)
Heat-treated state
UNS S31266 · ASTM A240/A312 · EN 1.4659
Joint condition without post-weld solution anneal; weld metal strength governs and pitting resistance drops at the fusion line.
Values for the AW condition
Other S31266 tempers and conditions
S31266 is listed in 4 conditions; see the grade overview at S31266.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AWThis page As-welded deposit | Joint condition without post-weld solution anneal; weld metal strength governs and pitting resistance drops at the fusion line. | 450 | 750 | 35 | 210 HB | 1.7 % IACS |
SADefault Solution Annealed | Standard supply condition for all product forms — maximum corrosion resistance and ductility. | 480 | 810 | 46 | 17 HRC | 1.7 % IACS |
Forged and Solution Annealed (ASTM A182 flanges/fittings) | For forged flanges, valve bodies and fittings; requires re-solution anneal and quench after forging. | 480 | 800 | 42 | 18 HRC | 1.7 % IACS |
Cold drawn | Use when higher strength and close tolerance are needed; ductility and formability are reduced. | 720 | 950 | 25 | 29 HRC | 1.7 % IACS |
What is S31266-AW?
S31266-AW is S31266 heat treated to AW — joint condition without post-weld solution anneal; weld metal strength governs and pitting resistance drops at the fusion line. S31266-AW has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 750 MPa (109 ksi) — stronger than 70% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 195 GPa (28.3 Msi). S31266-AW 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). SA is the default condition FabDigit quotes; AW is available on request or by drawing note.
Advantages
- Good corrosion resistance — 85/100, better than 92% of stainless steel grades
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 86% 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 — 20/100, worse than 98% of stainless steel grades
- Low electrical conductivity — 1.7 % IACS, worse than 93% of stainless steel grades
- High embodied carbon — 6 kg CO₂/kg, worse than 88% of stainless steel grades
- Limited service temperature — 400°C (752 °F), worse than 78% of stainless steel grades
S31266-AW properties
Typical room-temperature values for S31266-AW; 21 are specific to this condition. Other listed values are S31266 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
S31266-AW 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).
Mechanical17
S31266-AW has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 750 MPa (109 ksi) — stronger than 70% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
S31266-AW 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
S31266-AW conducts electricity at 1.7 % IACS, worse than 93% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 92% of stainless steel grades.
Sustainability4
Producing a kilogram of S31266-AW takes about 85 MJ of energy and emits 6 kg of CO₂ — more than 92% of stainless steel grades. Typical recycled content is 40%.
Manufacturability7
S31266-AW's machinability is poor (20/100, worse than 98% of stainless steel grades); weldability very good (70/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S31266-AW
Is S31266 easy to machine?
Very tough and work-hardening: use rigid setups, positive-rake carbide, heavy feed with no dwell, ~50–70 % of the speed used for 316L and copious high-pressure coolant.
Can S31266 be welded?
GTAW/GMAW/SMAW with over-alloyed Ni-base filler (ERNiCrMo-3, -13 or -14), low heat input, interpass <100 °C, no preheat and no PWHT; back-purge with Ar or Ar+N₂.
Can S31266 be formed, bent or molded?
Cold forms well but needs roughly double the press force of 304 and generous bend radii; hot work at 1100–1200 °C and solution anneal + water quench afterwards.
What surface finishes work on S31266?
Pickle/passivate with HNO₃-HF after hot work or welding to restore the passive film; electropolishing gives the best crevice and cleanability performance — do not anodise.
S31266 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 |
| Si | ≤ 1 | 0.4 |
| Mn | 2 – 4 | 3 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.02 | 0 |
| Cr | 23 – 25 | 24 |
| Ni | 21 – 24 | 22 |
| Mo | 5 – 7 | 6 |
| Cu | 0.5 – 2 | 1.3 |
| W | 1 – 3 | 2 |
| Nhigh nitrogen for strength and pitting resistance | 0.35 – 0.6 | 0.45 |
| Fe | balance | — |
S31266-AW — frequently asked
What is S31266-AW used for?
S31266-AW is typically used for flue-gas desulfurization, seawater and brine systems, chemical process equipment and oil & gas sour service piping. In short: nickel-alloy corrosion resistance; highest chloride resistance in family; sour service capable.
What is the yield strength of S31266-AW?
S31266-AW has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 750 MPa (109 ksi) — stronger than 70% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is S31266-AW easy to machine?
Not especially — machinability is rated poor (20/100, worse than 98% of stainless steel grades). Very tough and work-hardening: use rigid setups, positive-rake carbide, heavy feed with no dwell, ~50–70 % of the speed used for 316L and copious high-pressure coolant.
Can S31266-AW be welded?
Yes — weldability is rated very good (70/100). GTAW/GMAW/SMAW with over-alloyed Ni-base filler (ERNiCrMo-3, -13 or -14), low heat input, interpass <100 °C, no preheat and no PWHT; back-purge with Ar or Ar+N₂.
What surface finishes work on S31266-AW?
Pickle/passivate with HNO₃-HF after hot work or welding to restore the passive film; electropolishing gives the best crevice and cleanability performance — do not anodise.
Can S31266-AW be formed, bent or molded?
Cold forms well but needs roughly double the press force of 304 and generous bend radii; hot work at 1100–1200 °C and solution anneal + water quench afterwards.
What is the maximum service temperature of S31266-AW?
S31266-AW 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 S31266-SA and S31266-CD?
SA is the default condition — standard supply condition for all product forms — maximum corrosion resistance and ductility. CD: use when higher strength and close tolerance are needed; ductility and formability are reduced. Yield strength is 480 MPa in SA versus 720 MPa in CD.
Sources
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip — ASTM International (2023)
- ASTM A312/A312M — Seamless, Welded and Heavily Cold Worked Austenitic Stainless Steel Pipes — ASTM International (2022)
- ASTM A479/A479M — Stainless Steel Bars and Shapes for Pressure Vessels — ASTM International (2023)
- UR B66 / UNS S31266 superaustenitic stainless steel datasheet — Industeel (ArcelorMittal) (2020)
- 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.