Stainless Steel S31655
UNS S31655
S31655 is a low-carbon, molybdenum-enriched austenitic stainless related to the 317L family, using the higher Mo level for improved pitting and crevice corrosion resistance in chemical process equipment.
Reference datasheet — S31655 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
S31655 tempers and conditions
S31655 is supplied in 7 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled | Heavy plate and hot-finished bar as supplied before or without a separate cold finish; properties close to annealed. | 275 | 590 | 45 | 165 HB | 2.2 % IACS |
AnnealedDefault solution annealed (~1040–1120 °C, water quenched) | Standard stocked condition for plate, sheet, pipe and bar; maximum corrosion resistance and ductility. | 280 | 600 | 50 | 160 HB | — |
Cold drawn | Pick for machined bar stock needing tighter tolerance, better surface and ~50 % higher yield than annealed. | 520 | 720 | 25 | 18 HRC | 2.2 % IACS |
Quarter hard | Light cold work for structural sheet where some forming ability must be retained. | 550 | 880 | 12 | 25 HRC | 2.2 % IACS |
Half hard | Higher-strength flat product for springs, clamps and lightweight structures; limited bending. | 790 | 1,050 | 9 | 32 HRC | 2.2 % IACS |
Three-quarter hard | Near-maximum cold-rolled strength for flat parts formed only by shallow bends. | 950 | 1,160 | 6 | 36 HRC | 2.2 % IACS |
Full hard | Maximum strength strip for shims, straps and spring elements; essentially no formability. | 1,000 | 1,300 | 5 | 40 HRC | 2.2 % IACS |
What is S31655?
S31655 is a low-carbon, molybdenum-enriched austenitic stainless related to the 317L family, using the higher Mo level for improved pitting and crevice corrosion resistance in chemical process equipment. Annealed product runs 280 MPa yield, 600 MPa tensile, 50 % elongation and about 160 HB (83 HRB), with high weldability (82) and formability (80) scores; it is available annealed, hot rolled, cold drawn and in 1/4, 1/2, 3/4 and full hard tempers. The Mo content raises price and narrows availability versus 316L, and the alloy work-hardens strongly in forming and machining; 317L is the closest common substitute. S31655 has a density of 7.98 g/cm³ (0.288 lb/in³), heavier than 85% of stainless steel grades. It melts at 1,375°C (2,507 °F). S31655 has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 75% of stainless steel grades. Elongation at break is 50% and the elastic modulus is 200 GPa (29 Msi).
What is S31655 used for?
- Chemical processing vessels
- Pulp and paper bleach-plant equipment
- Process piping and fittings
- Heat exchanger shells and tube sheets
- Scrubber and flue-gas desulfurization internals
- Tanks and agitator shafts for chloride-bearing liquors
- Pump and valve bodies
Advantages
- Tough — resists crack growth — 220 MPa·√m (200.2 ksi·√in), better than 97% of stainless steel grades
- Forms and bends easily — 80/100, better than 93% of stainless steel grades
- Ductile — tolerates forming and impact — 50%, better than 90% of stainless steel grades
- Readily welded — 82/100, better than 84% of stainless steel grades
- High service temperature — 850°C (1,562 °F), better than 80% of stainless steel grades
Limitations
- High embodied carbon — 5.5 kg CO₂/kg, worse than 77% of stainless steel grades
- Low strength — 280 MPa (40.6 ksi), worse than 75% of stainless steel grades
S31655 properties
Typical room-temperature values for S31655-Annealed; bars are the position among stainless steel grades.
Physical3
S31655 has a density of 7.98 g/cm³ (0.288 lb/in³), heavier than 85% of stainless steel grades. It melts at 1,375°C (2,507 °F).
Mechanical16
S31655 has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 75% of stainless steel grades. Elongation at break is 50% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S31655 is rated for continuous service to 850°C (1,562 °F). It conducts heat at 14.5 W/m·K (8.38 BTU/hr·ft·°F), worse than 72% of stainless steel grades. Thermal expansion is 16 µm/m·K (8.89 µin/in·°F).
Electrical3
S31655 conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (74/100), better than 78% of stainless steel grades.
Sustainability4
Producing a kilogram of S31655 takes about 57 MJ of energy and emits 5.5 kg of CO₂ — more than 62% of stainless steel grades. Typical recycled content is 65%.
Manufacturability6
S31655's machinability is poor (32/100, worse than 62% of stainless steel grades); weldability very good (82/100); formability very good (80/100).
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. S31655 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S31655
Is S31655 easy to machine?
Cuts like 317L: rigid setup, sharp positive-rake carbide, heavy feed to stay under the work-hardened skin, 40–70 m/min with flood emulsion; avoid dwelling.
Can S31655 be welded?
Readily welded by GTAW/GMAW/SMAW without preheat or PWHT; use over-alloyed filler (ER317L, or Ni-base ERNiCrMo-3 for as-welded corrosion service) and keep interpass below ~150 °C.
Can S31655 be formed, bent or molded?
Excellent cold formability and deep drawing, but high work-hardening rate means 40–60 % more press force than carbon steel and intermediate solution anneals for severe draws; hot work 1150–1200 °C then solution anneal.
S31655 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 grade, limits sensitization | ≤ 0.03 | 0.02 |
| Si | ≤ 1 | 0.5 |
| Mn | ≤ 2 | 1.5 |
| P | ≤ 0.05 | 0.03 |
| S | ≤ 0.03 | 0.01 |
| Cr317L-family range | 18 – 20 | 19 |
| Niraised to stabilize austenite against high Mo | 13 – 17 | 14.5 |
| Mosource of the enhanced pitting/crevice resistance | 3 – 4 | 3.4 |
| Nnitrogen-bearing variants of this family raise strength and PREN | ≤ 0.2 | 0.1 |
| Fe | balance |
What surface finishes work on S31655?
Pickle and passivate (nitric or citric per ASTM A967) after welding or grinding; takes 2B, No.4 brush and No.8 mirror polish well — no anodizing, electropolishing is the preferred high-purity finish.
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
How much does S31655 cost?
S31655 is a premium-cost stainless steel ($$$), cheaper than about 51% 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.
S31655 — frequently asked
What is S31655 used for?
S31655 is typically used for chemical processing vessels, pulp and paper bleach-plant equipment, process piping and fittings, heat exchanger shells and tube sheets, scrubber and flue-gas desulfurization internals and tanks and agitator shafts for chloride-bearing liquors. In short: 317L-class pitting resistance; highly formable Mo austenitic; weldability score 82.
What is the yield strength of S31655?
S31655 has a typical yield strength of 280 MPa (40.6 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 75% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is S31655 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 62% of stainless steel grades). Cuts like 317L: rigid setup, sharp positive-rake carbide, heavy feed to stay under the work-hardened skin, 40–70 m/min with flood emulsion; avoid dwelling.
Can S31655 be welded?
Yes — weldability is rated very good (82/100). Readily welded by GTAW/GMAW/SMAW without preheat or PWHT; use over-alloyed filler (ER317L, or Ni-base ERNiCrMo-3 for as-welded corrosion service) and keep interpass below ~150 °C.
What surface finishes work on S31655?
Pickle and passivate (nitric or citric per ASTM A967) after welding or grinding; takes 2B, No.4 brush and No.8 mirror polish well — no anodizing, electropolishing is the preferred high-purity finish.
Can S31655 be formed, bent or molded?
Excellent cold formability and deep drawing, but high work-hardening rate means 40–60 % more press force than carbon steel and intermediate solution anneals for severe draws; hot work 1150–1200 °C then solution anneal.
What is the maximum service temperature of S31655?
S31655 is rated for continuous use to about 850°C (1,562 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S31655 Annealed and S31655-FH?
Annealed is the default condition — standard stocked condition for plate, sheet, pipe and bar; maximum corrosion resistance and ductility. FH: maximum strength strip for shims, straps and spring elements; essentially no formability. Yield strength is 280 MPa in Annealed versus 1,000 MPa in FH.
How much does S31655 cost?
S31655 is a premium-cost stainless steel ($$$), cheaper than about 51% 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 A276/A276M — Stainless Steel Bars and Shapes — ASTM International (2023)
- ASTM A666 — Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate and Flat Bar — ASTM International (2015)
- SAE J1086 / UNS Metals and Alloys Numbering System — SAE International / ASTM (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- 317L / 317LMN austenitic stainless steel datasheets — Outokumpu (2022)
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.