Stainless Steel S31254
UNS S31254 · ASTM A240/A276/A312 · EN 1.4547, X1CrNiMoCuN20-18-7 · JIS SUS890L
6% Mo superaustenitic grade with very high PRE (~43), offering excellent resistance to chloride pitting/crevice corrosion; the archetypal seawater-grade stainless used where 316L/904L are insufficient.
Reference datasheet — S31254 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
S31254 tempers and conditions
S31254 is supplied in 5 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Forged + solution annealed | Flanges, valve bodies and heavy fittings; must be re-solution annealed after forging to dissolve intermetallics. | 330 | 670 | 45 | 200 HB | 2 % IACS |
AnnealedDefault solution annealed ~1150–1200 °C + rapid quench (Condition A) | Standard stocked condition for plate, bar, pipe and fittings; maximum corrosion resistance and ductility. | 350 | 680 | 50 | 200 HB | — |
Cold drawn | Pick for shafts, bolting and machined fittings needing higher strength and tight tolerances than annealed bar. | 550 | 800 | 25 | 25 HRC | 2 % IACS |
1/4 Hard | Springy strip/shim and lightly formed parts where extra strength is wanted and corrosion demands stay high. | 620 | 860 | 15 | 28 HRC | 2 % IACS |
1/2 Hard | Highest-strength strip condition offered; only for flat/lightly bent parts, ductility is much reduced. | 800 | 1,000 | 10 | 32 HRC | 2 % IACS |
Supply forms, finishes and certifications
Ways S31254 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
TUBE-A | Annealed tube/pipe | Supply form |
2B | Cold rolled, annealed, pickled, lightly skin-passed sheet | Surface finish |
BA | BA | Surface finish |
HRAP-1D | 1D / HRAP | Surface finish |
What is S31254?
6% Mo superaustenitic grade with very high PRE (~43), offering excellent resistance to chloride pitting/crevice corrosion; the archetypal seawater-grade stainless used where 316L/904L are insufficient. S31254 has a density of 8 g/cm³ (0.289 lb/in³), heavier than 92% of stainless steel grades. It melts at 1,325°C (2,417 °F). S31254 has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 52% of stainless steel grades. Elongation at break is 50% and the elastic modulus is 195 GPa (28.3 Msi).
What is S31254 used for?
- seawater piping and heat exchangers
- desalination equipment
- pulp and paper bleaching plants
- flue gas desulfurization systems
- offshore and marine hardware
Advantages
- Good corrosion resistance — 88/100, better than 97% of stainless steel grades
- Ductile — tolerates forming and impact — 50%, better than 90% of stainless steel grades
- Polishes to a fine finish — 80/100, better than 89% of stainless steel grades
Limitations
- High embodied carbon — 6.2 kg CO₂/kg, worse than 90% of stainless steel grades
- Difficult to machine — 25/100, worse than 88% of stainless steel grades
- Limited service temperature — 400°C (752 °F), worse than 78% of stainless steel grades
- Low electrical conductivity — 2 % IACS, worse than 77% of stainless steel grades
S31254 properties
Typical room-temperature values for S31254-Annealed; bars are the position among stainless steel grades.
Physical3
S31254 has a density of 8 g/cm³ (0.289 lb/in³), heavier than 92% of stainless steel grades. It melts at 1,325°C (2,417 °F).
Mechanical15
S31254 has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 52% of stainless steel grades. Elongation at break is 50% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
S31254 is rated for continuous service to 400°C (752 °F). It conducts heat at 14 W/m·K (8.09 BTU/hr·ft·°F), worse than 80% of stainless steel grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
S31254 conducts electricity at 2 % IACS, worse than 77% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), better than 97% of stainless steel grades.
Sustainability4
Producing a kilogram of S31254 takes about 90 MJ of energy and emits 6.2 kg of CO₂ — more than 94% of stainless steel grades. Typical recycled content is 45%.
Manufacturability7
S31254's machinability is poor (25/100, worse than 88% of stainless steel grades); weldability very good (70/100); formability good (60/100).
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. S31254 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S31254
Is S31254 easy to machine?
Machines like a heavily work-hardening austenitic: use rigid setups, positive-rake sharp carbide, low speed with heavy feed, generous flood coolant, and never let the tool dwell — expect roughly 30% of 1212 rates.
Can S31254 be welded?
GTAW/GMAW/SMAW with over-alloyed Ni-base filler (ERNiCrMo-3 / 625 type) to keep weld-metal PREN up; low heat input, no preheat, interpass below ~150 °C, and post-weld pickling of heat tint.
Can S31254 be formed, bent or molded?
Cold forms well but needs ~2× the press force of 304 and generous springback allowance; hot work 1150–1200 °C and always solution anneal and quench afterwards.
S31254 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 to avoid sensitization | ≤ 0.02 | 0.01 |
| Si | ≤ 0.8 | 0.4 |
| Mn | ≤ 1 | 0.6 |
| P | ≤ 0.03 | |
| S | ≤ 0.01 | |
| Cr | 19.5 – 20.5 | 20 |
| Ni | 17.5 – 18.5 | 18 |
| Mo6Mo grade, drives PREN ≈ 43 | 6 – 6.5 | 6.2 |
| Cuimproves resistance in reducing acids | 0.5 – 1 | 0.7 |
| Naustenite stabilizer, boosts strength and pitting resistance | 0.18 – 0.25 | 0.2 |
| Fe | balance |
What surface finishes work on S31254?
Pickle/passivate or electropolish to restore the chloride-resistant passive film; grind out heat tint and embedded iron, do not anodize.
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 S31254 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does S31254 cost?
S31254 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.
S31254 — frequently asked
What is S31254 used for?
S31254 is typically used for seawater piping and heat exchangers, desalination equipment, pulp and paper bleaching plants, flue gas desulfurization systems and offshore and marine hardware. In short: seawater-grade 6% Mo stainless; PRE around 43; upgrade from 316L/904L.
What is the yield strength of S31254?
S31254 has a typical yield strength of 350 MPa (50.8 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 52% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is S31254 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 88% of stainless steel grades). Machines like a heavily work-hardening austenitic: use rigid setups, positive-rake sharp carbide, low speed with heavy feed, generous flood coolant, and never let the tool dwell — expect roughly 30% of 1212 rates.
Can S31254 be welded?
Yes — weldability is rated very good (70/100). GTAW/GMAW/SMAW with over-alloyed Ni-base filler (ERNiCrMo-3 / 625 type) to keep weld-metal PREN up; low heat input, no preheat, interpass below ~150 °C, and post-weld pickling of heat tint.
What surface finishes work on S31254?
Pickle/passivate or electropolish to restore the chloride-resistant passive film; grind out heat tint and embedded iron, do not anodize.
Can S31254 be formed, bent or molded?
Cold forms well but needs ~2× the press force of 304 and generous springback allowance; hot work 1150–1200 °C and always solution anneal and quench afterwards.
What is the maximum service temperature of S31254?
S31254 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 S31254 Annealed and S31254-CD?
Annealed is the default condition — standard stocked condition for plate, bar, pipe and fittings; maximum corrosion resistance and ductility. CD: pick for shafts, bolting and machined fittings needing higher strength and tight tolerances than annealed bar. Yield strength is 350 MPa in Annealed versus 550 MPa in CD.
How much does S31254 cost?
S31254 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 International (2023)
- ASTM A312/A276/A479/A182 (F44) — pipe, bar and forging specifications — ASTM International (2022)
- EN 10088-2 — Stainless steels: sheet/plate, grade 1.4547 (X1CrNiMoCuN20-18-7) — CEN (2014)
- 254 SMO / S31254 alloy datasheet (physical, mechanical and corrosion data) — Outokumpu (2023)
- 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; 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.