Stainless Steel S81921 Annealed
Temper · default condition
UNS S81921
Standard supply condition for plate, sheet, bar, pipe and fittings; balanced ferrite/austenite with optimum corrosion resistance and toughness.
Values for the Annealed condition
Other S81921 tempers and conditions
S81921 is listed in 5 conditions; see the grade overview at S81921.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Welded & annealed tube/pipe (ASTM A789/A790 class) | Standard condition for welded pipe and tubing — post-weld solution anneal restores phase balance and corrosion performance across the weld. | 515 | 720 | 32 | 22 HRC | 2.2 % IACS |
AnnealedDefaultThis page solution annealed (~1020–1100 °C) and rapid water quenched | Standard supply condition for plate, sheet, bar, pipe and fittings; balanced ferrite/austenite with optimum corrosion resistance and toughness. | 520 | 730 | 35 | 21 HRC | — |
Cold drawn | Pick for bar, shafting and fasteners needing tighter tolerance, better straightness and higher yield strength than annealed bar. | 700 | 860 | 20 | 28 HRC | 2.2 % IACS |
Quarter hard | Light cold work for strip and structural profiles where extra yield strength is wanted with usable bendability. | 720 | 900 | 18 | 30 HRC | 2.2 % IACS |
Half hard | For springy strip, clamps and weight-optimised structural strip where high strength beats formability. | 850 | 1,020 | 12 | 34 HRC | 2.2 % IACS |
What is S81921 Annealed?
S81921 Annealed is S81921 in the Annealed temper — standard supply condition for plate, sheet, bar, pipe and fittings; balanced ferrite/austenite with optimum corrosion resistance and toughness. S81921 Annealed has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 730 MPa (106 ksi) — stronger than 79% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 200 GPa (29 Msi). S81921 Annealed has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,420°C (2,588 °F).
Advantages
- Low embodied carbon — 3.6 kg CO₂/kg, better than 83% of stainless steel grades
- High strength — 520 MPa (75.4 ksi), better than 79% of stainless steel grades
Limitations
- Limited service temperature — 280°C (536 °F), worse than 96% of stainless steel grades
S81921 Annealed properties
Typical room-temperature values for S81921 Annealed; 11 are specific to this condition. Other listed values are S81921 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
S81921 Annealed has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,420°C (2,588 °F).
Mechanical17
S81921 Annealed has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 730 MPa (106 ksi) — stronger than 79% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S81921 Annealed is rated for continuous service to 280°C (536 °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
S81921 Annealed conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (63/100), better than 53% of stainless steel grades.
Sustainability4
Producing a kilogram of S81921 Annealed takes about 52 MJ of energy and emits 3.6 kg of CO₂ — less than 76% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
S81921 Annealed's machinability is fair (40/100, better than 72% of stainless steel grades); weldability very good (70/100); formability good (55/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S81921 Annealed
Is S81921 easy to machine?
Cuts like a tough, work-hardening duplex: use rigid setups, sharp positive-rake carbide, heavy feeds with no dwell, ~60–70 % of 304 speeds and flood coolant.
Can S81921 be welded?
Weld with GTAW/GMAW/SMAW using 2209 or matching lean-duplex filler and Ar+2%N₂ backing; keep heat input ~0.5–2.0 kJ/mm and interpass <150 °C to hold ~50/50 ferrite-austenite; no preheat, no post-weld temper in the 300–1000 °C range.
Can S81921 be formed, bent or molded?
Cold forms well but needs roughly twice the press force of 304 with large springback allowance; hot form at 950–1150 °C followed by full solution anneal and water quench.
What surface finishes work on S81921?
Pickle and passivate (HNO₃-HF) after hot work or welding to remove heat tint; can be mechanically polished, bead blasted or electropolished — no anodizing.
S81921 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 |
| MnMn substitutes for Ni and stabilises N solubility | 2 – 4 | 3 |
| Si | ≤ 1 | 0.5 |
| P | ≤ 0.04 | 0.03 |
| S | ≤ 0.03 | 0 |
| Cr | 19 – 21.5 | 20 |
| Nilean-Ni design | 2 – 4 | 3 |
| Momax; usually residual level | ≤ 1 | 0.3 |
| Cu | ≤ 1 | 0.3 |
| Naustenite stabiliser, raises strength and pitting resistance | 0.14 – 0.2 | 0.17 |
| Fe | balance | — |
S81921 Annealed — frequently asked
What is S81921 Annealed used for?
S81921 Annealed is typically used for storage tanks, structural components, transport tankers and low-chloride process equipment. In short: low-nickel duplex, lower cost; twice the yield of 304; below 2205 in pitting.
What is the yield strength of S81921 Annealed?
S81921 Annealed has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 730 MPa (106 ksi) — stronger than 79% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is S81921 Annealed easy to machine?
Not especially — machinability is rated fair (40/100, better than 72% of stainless steel grades). Cuts like a tough, work-hardening duplex: use rigid setups, sharp positive-rake carbide, heavy feeds with no dwell, ~60–70 % of 304 speeds and flood coolant.
Can S81921 Annealed be welded?
Yes — weldability is rated very good (70/100). Weld with GTAW/GMAW/SMAW using 2209 or matching lean-duplex filler and Ar+2%N₂ backing; keep heat input ~0.5–2.0 kJ/mm and interpass <150 °C to hold ~50/50 ferrite-austenite; no preheat, no post-weld temper in the 300–1000 °C range.
What surface finishes work on S81921 Annealed?
Pickle and passivate (HNO₃-HF) after hot work or welding to remove heat tint; can be mechanically polished, bead blasted or electropolished — no anodizing.
Can S81921 Annealed be formed, bent or molded?
Cold forms well but needs roughly twice the press force of 304 with large springback allowance; hot form at 950–1150 °C followed by full solution anneal and water quench.
What is the maximum service temperature of S81921 Annealed?
S81921 Annealed 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 S81921 Annealed and S81921-CD?
Annealed is the default condition — standard supply condition for plate, sheet, bar, pipe and fittings; balanced ferrite/austenite with optimum corrosion resistance and toughness. CD: pick for bar, shafting and fasteners needing tighter tolerance, better straightness and higher yield strength than annealed bar. Yield strength is 520 MPa in Annealed versus 700 MPa in CD.
Sources
- ASTM A240/A240M — 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 (2021)
- ASTM A276/A479 — Stainless Steel Bars and Shapes — ASTM International (2022)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Practical Guidelines for the Fabrication of Duplex Stainless Steels — IMOA (2014)
- Lean duplex stainless steel plate/coil datasheets (2101/2003-class) — Outokumpu / TISCO / Baosteel (2023)
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.