Stainless Steel S31100 Annealed
Temper · default condition
UNS S31100 · AISI/SAE XM-26
Standard supply condition for plate, sheet, bar and pipe; best corrosion resistance and toughness with full duplex phase balance.
Values for the Annealed condition
Other S31100 tempers and conditions
S31100 is listed in 6 conditions; see the grade overview at S31100.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled | Thick plate and hot-finished bar for pressure vessels and structural parts where scale/tolerance is machined off. | 490 | 750 | 30 | 22 HRC | 2.2 % IACS |
AnnealedDefaultThis page solution annealed and quenched (mill annealed) | Standard supply condition for plate, sheet, bar and pipe; best corrosion resistance and toughness with full duplex phase balance. | 500 | 760 | 30 | 23 HRC | 2.2 % IACS |
As-welded deposit | Reference condition for welded fabrications; expect reduced toughness and pitting resistance unless heat input and filler ferrite balance are controlled. | 500 | 750 | 22 | 24 HRC | 2.2 % IACS |
Cold Rolled + Annealed, 2B finish | Thin sheet and strip for tanks, heat-exchanger and formed components needing a smooth bright surface. | 520 | 780 | 28 | 24 HRC | 2.2 % IACS |
Cold drawn | Cold-drawn bar for shafts, fasteners and machined fittings where tighter tolerance and higher yield are wanted. | 700 | 880 | 20 | 29 HRC | 2.2 % IACS |
Cold Worked, high strength | Choose when maximum strength in small sections matters and ductility/toughness can be traded away; not for welded or SCC-critical service. | 830 | 1,000 | 13 | 33 HRC | 2.2 % IACS |
What is S31100 Annealed?
S31100 Annealed is S31100 in the Annealed temper — standard supply condition for plate, sheet, bar and pipe; best corrosion resistance and toughness with full duplex phase balance. S31100 Annealed has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 77% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi). S31100 Annealed has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Advantages
- 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
S31100 Annealed properties
Typical room-temperature values for S31100 Annealed; 23 are specific to this condition. Other listed values are S31100 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
S31100 Annealed has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical17
S31100 Annealed has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 77% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi).
Thermal5
S31100 Annealed is rated for continuous service to 300°C (572 °F). It conducts heat at 15.5 W/m·K (8.96 BTU/hr·ft·°F), better than 53% of stainless steel grades. Thermal expansion is 13 µm/m·K (7.22 µin/in·°F).
Electrical3
S31100 Annealed conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 63% of stainless steel grades.
Sustainability4
Producing a kilogram of S31100 Annealed takes about 53 MJ of energy and emits 4.6 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 65%.
Manufacturability8
S31100 Annealed's machinability is poor (33/100, worse than 57% of stainless steel grades); weldability good (62/100); formability fair (48/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S31100 Annealed
Is S31100 easy to machine?
Machine like 2205: rigid setups, positive-rake carbide, ~30 % of 1212 speeds, heavy feed to cut through the work-hardened skin, flood coolant.
Can S31100 be welded?
GTAW/GMAW/SMAW with 22-9-3 or 25-9-4 over-alloyed filler, no preheat, limited heat input (~0.5–1.5 kJ/mm) and interpass below ~150 °C to keep 40–60 % ferrite; avoid autogenous welds.
Can S31100 be formed, bent or molded?
Cold form with roughly twice the load of 316L and generous springback allowance; hot work 1000–1150 °C followed by solution anneal ~1050 °C and rapid quench.
What surface finishes work on S31100?
Pickle and passivate after welding to restore the passive film; electropolishing or mechanical polishing gives a durable bright finish — no anodizing.
S31100 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 practice | ≤ 0.08 | 0.03 |
| Crconfirm against governing ASTM/UNS listing | 17.5 – 19.5 | 18.5 |
| Ni | 4.5 – 6.5 | 5.5 |
| Mo | 2.5 – 3 | 2.8 |
| Mn | ≤ 2 | 1.2 |
| Si | ≤ 1.5 | 0.6 |
| Naustenite stabiliser, raises pitting resistance | 0.03 – 0.1 | 0.07 |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
S31100 Annealed — frequently asked
What is S31100 Annealed used for?
S31100 Annealed is typically used for chemical process piping, pulp and paper equipment and heat exchangers. In short: moderate-cost lean duplex; better chloride resistance than 316; largely superseded by 2205.
What is the yield strength of S31100 Annealed?
S31100 Annealed has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 77% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is S31100 Annealed easy to machine?
Not especially — machinability is rated poor (33/100, worse than 57% of stainless steel grades). Machine like 2205: rigid setups, positive-rake carbide, ~30 % of 1212 speeds, heavy feed to cut through the work-hardened skin, flood coolant.
Can S31100 Annealed be welded?
Yes — weldability is rated good (62/100). GTAW/GMAW/SMAW with 22-9-3 or 25-9-4 over-alloyed filler, no preheat, limited heat input (~0.5–1.5 kJ/mm) and interpass below ~150 °C to keep 40–60 % ferrite; avoid autogenous welds.
What surface finishes work on S31100 Annealed?
Pickle and passivate after welding to restore the passive film; electropolishing or mechanical polishing gives a durable bright finish — no anodizing.
Can S31100 Annealed be formed, bent or molded?
Cold form with roughly twice the load of 316L and generous springback allowance; hot work 1000–1150 °C followed by solution anneal ~1050 °C and rapid quench.
What is the maximum service temperature of S31100 Annealed?
S31100 Annealed 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 S31100 Annealed and S31100 CW-HS?
Annealed is the default condition — standard supply condition for plate, sheet, bar and pipe; best corrosion resistance and toughness with full duplex phase balance. CW-HS: choose when maximum strength in small sections matters and ductility/toughness can be traded away; not for welded or SCC-critical service. Yield strength is 500 MPa in Annealed versus 830 MPa in CW-HS.
Sources
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet and Strip — ASTM International (2023)
- ASTM A276/A479 — Stainless Steel Bars and Shapes — ASTM International (2022)
- Unified Numbering System for Metals and Alloys (UNS) — SAE/ASTM (2020)
- 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)
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.