Stainless Steel S31200-AW (As-welded deposit)
Heat-treated state
UNS S31200
Reference condition for fabricated joints — properties of weld metal/HAZ when no post-weld solution anneal is performed.
Values for the AW condition
Other S31200 tempers and conditions
S31200 is listed in 4 conditions; see the grade overview at S31200.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Forged, Solution Annealed (ASTM A182 F-type duplex forging) | For flanges, valve bodies and heavy sections; requires post-forge solution anneal and rapid quench to dissolve sigma phase. | 510 | 750 | 30 | 23 HRC | 2.2 % IACS |
SADefault Solution Annealed | Standard supply condition for plate, pipe and bar — best balance of strength, ductility and corrosion resistance. | 530 | 770 | 32 | 24 HRC | 2.2 % IACS |
AWThis page As-welded deposit | Reference condition for fabricated joints — properties of weld metal/HAZ when no post-weld solution anneal is performed. | 540 | 750 | 25 | 25 HRC | 2.2 % IACS |
Cold drawn | Choose for shafts, fasteners and machined fittings needing tighter tolerance and ~15–25 % higher yield than annealed. | 680 | 880 | 20 | 29 HRC | 2.2 % IACS |
What is S31200-AW?
S31200-AW is S31200 heat treated to AW — reference condition for fabricated joints — properties of weld metal/HAZ when no post-weld solution anneal is performed. S31200-AW has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 750 MPa (109 ksi) — stronger than 82% of stainless steel grades. Elongation at break is 25% and the elastic modulus is 200 GPa (29 Msi). S31200-AW has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,385°C (2,525 °F). SA is the default condition FabDigit quotes; AW is available on request or by drawing note.
Advantages
- High strength — 540 MPa (78.3 ksi), better than 82% of stainless steel grades
Limitations
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
- Low fracture toughness — 90 MPa·√m (81.9 ksi·√in), worse than 75% of stainless steel grades
S31200-AW properties
Typical room-temperature values for S31200-AW; 22 are specific to this condition. Other listed values are S31200 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
S31200-AW has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,385°C (2,525 °F).
Mechanical17
S31200-AW has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 750 MPa (109 ksi) — stronger than 82% of stainless steel grades. Elongation at break is 25% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S31200-AW 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 13 µm/m·K (7.22 µin/in·°F).
Electrical3
S31200-AW conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 68% of stainless steel grades.
Sustainability4
Producing a kilogram of S31200-AW takes about 55 MJ of energy and emits 4.5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 65%.
Manufacturability8
S31200-AW's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability good (65/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S31200-AW
Is S31200 easy to machine?
Machine like 2205: rigid setup, positive-rake carbide, ~25 % of 1212 speeds, heavy constant feed and flood coolant to avoid work hardening and glazing.
Can S31200 be welded?
Weldable by GTAW/GMAW/SMAW with 25Cr over-alloyed filler (e.g. ER2209/25.10.4L); keep heat input ~0.5–2.5 kJ/mm, interpass <150 °C, no preheat, back-purge with Ar (+N₂) and avoid PWHT unless full re-solution anneal is possible.
Can S31200 be formed, bent or molded?
Cold form with ~2× the force of 304 and allow for high springback; hot form 950–1150 °C followed by full solution anneal and water quench — never finish forming in the 300–1000 °C embrittlement range.
What surface finishes work on S31200?
Pickle and passivate after welding or hot work (HNO₃/HF paste, per ASTM A380/A967); electropolishing gives the best chloride-service surface — anodizing does not apply.
S31200 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 duplex | ≤ 0.03 | 0.02 |
| Mn | ≤ 2 | 1.2 |
| Si | ≤ 1 | 0.5 |
| P | ≤ 0.05 | — |
| S | ≤ 0.03 | — |
| Cr | 24 – 26 | 25 |
| Ni | 5.5 – 6.5 | 6 |
| Mo | 1.2 – 2 | 1.7 |
| Naustenite stabiliser, boosts pitting resistance | 0.14 – 0.2 | 0.17 |
| Fe | balance | — |
S31200-AW — frequently asked
What is S31200-AW used for?
S31200-AW is typically used for chemical process piping, pressure vessels and heat exchangers. In short: 2205-equivalent duplex performance; high chloride SCC resistance; limited mill availability.
What is the yield strength of S31200-AW?
S31200-AW has a typical yield strength of 540 MPa (78.3 ksi) and a tensile strength of 750 MPa (109 ksi) — stronger than 82% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is S31200-AW easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Machine like 2205: rigid setup, positive-rake carbide, ~25 % of 1212 speeds, heavy constant feed and flood coolant to avoid work hardening and glazing.
Can S31200-AW be welded?
Yes — weldability is rated good (65/100). Weldable by GTAW/GMAW/SMAW with 25Cr over-alloyed filler (e.g. ER2209/25.10.4L); keep heat input ~0.5–2.5 kJ/mm, interpass <150 °C, no preheat, back-purge with Ar (+N₂) and avoid PWHT unless full re-solution anneal is possible.
What surface finishes work on S31200-AW?
Pickle and passivate after welding or hot work (HNO₃/HF paste, per ASTM A380/A967); electropolishing gives the best chloride-service surface — anodizing does not apply.
Can S31200-AW be formed, bent or molded?
Cold form with ~2× the force of 304 and allow for high springback; hot form 950–1150 °C followed by full solution anneal and water quench — never finish forming in the 300–1000 °C embrittlement range.
What is the maximum service temperature of S31200-AW?
S31200-AW 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 S31200-SA and S31200-CD?
SA is the default condition — standard supply condition for plate, pipe and bar — best balance of strength, ductility and corrosion resistance. CD: choose for shafts, fasteners and machined fittings needing tighter tolerance and ~15–25 % higher yield than annealed. Yield strength is 530 MPa in SA versus 680 MPa in CD.
Sources
- ASTM A240/A240M Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip — ASTM International (2023)
- ASTM A789/A790 Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing and Pipe — ASTM International (2023)
- ASTM A182/A182M Forged or Rolled Pipe Flanges, Fittings, Valves and Parts — ASTM International (2022)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (duplex stainless section) — ASM International (1990)
- Practical Guidelines for the Fabrication of Duplex Stainless Steels — IMOA / International Molybdenum Association (2014)
- 44LN / duplex 25Cr-6Ni-Mo-N alloy datasheet — Sandvik / Outokumpu (Avesta) (2020)
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.