Stainless Steel S31655-FH (Full hard)
Supply condition
UNS S31655
Maximum strength strip for shims, straps and spring elements; essentially no formability.
Values for the FH condition
Other S31655 tempers and conditions
S31655 is listed in 7 conditions; see the grade overview at S31655.
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 |
FHThis page 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-FH?
S31655-FH is S31655 supplied in the FH condition — maximum strength strip for shims, straps and spring elements; essentially no formability. S31655-FH has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,300 MPa (189 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 5% and the elastic modulus is 195 GPa (28.3 Msi). S31655-FH 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). Annealed is the default condition FabDigit quotes; FH is available on request or by drawing note.
Advantages
- High strength — 1,000 MPa (145 ksi), better than 98% of stainless steel grades
Limitations
- Limited ductility — 5%, worse than 100% of stainless steel grades
- Limited formability — 12/100, worse than 93% of stainless steel grades
- Difficult to machine — 25/100, worse than 88% of stainless steel grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 77% of stainless steel grades
S31655-FH properties
Typical room-temperature values for S31655-FH; 23 are specific to this condition. Other listed values are S31655 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
S31655-FH 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-FH has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,300 MPa (189 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 5% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
S31655-FH is rated for continuous service to 425°C (797 °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-FH 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 S31655-FH 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-FH's machinability is poor (25/100, worse than 88% of stainless steel grades); weldability good (60/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S31655-FH
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.
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.
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 | — |
S31655-FH — frequently asked
What is S31655-FH used for?
S31655-FH 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-FH?
S31655-FH has a typical yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,300 MPa (189 ksi) — stronger than 98% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is S31655-FH easy to machine?
Not especially — machinability is rated poor (25/100, worse than 88% 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-FH be welded?
Yes — weldability is rated good (60/100). 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-FH?
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-FH 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-FH?
S31655-FH is rated for continuous use to about 425°C (797 °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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.