Stainless Steel S31730 Full Hard
Supply condition
UNS S31730
Maximum as-rolled strength for springs and flat gaskets; brittle in bending and prone to distortion on welding.
Values for the Full Hard condition
Other S31730 tempers and conditions
S31730 is listed in 9 conditions; see the grade overview at S31730.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot Rolled (plate, annealed and descaled) | Heavy plate route for pressure vessels and process tanks; properties essentially those of the annealed condition. | 250 | 570 | 45 | 170 HB | 2.3 % IACS |
AnnealedDefault solution annealed (~1040–1120 °C, rapid cool) | Standard stocked condition for plate, sheet, tube and bar; maximum corrosion resistance and ductility. | 255 | 580 | 45 | 165 HB | — |
weld metal / heat-affected zone, no post-weld heat treatment | Reference condition for fabricated equipment: Ti stabilization keeps the HAZ resistant to intergranular attack without post-weld solution annealing. | 280 | 560 | 35 | 180 HB | 2.2 % IACS |
low-temperature stabilizing/stress relief after cold work or welding | Used on cold-worked or welded assemblies to reduce residual stress and SCC risk while keeping most cold-work strength; Ti stabilization tolerates the hold without sensitization. | 450 | 700 | 30 | 200 HB | 2.3 % IACS |
bar/wire, lightly cold worked and straightened | Choose for machined fittings, shafts and fasteners needing higher yield and better surface than annealed bar. | 550 | 760 | 25 | 220 HB | 2.3 % IACS |
Quarter hard | Light temper rolling when moderate strength must be combined with some bending ability. | 560 | 900 | 20 | 250 HB | 2.3 % IACS |
Half hard | For springy clips, straps and stiff panels where forming is limited to gentle radii. | 800 | 1,070 | 12 | 32 HRC | 2.3 % IACS |
Three-quarter hard | High-strength flat strip for shims and spring washers; forming essentially limited to flat blanking. | 960 | 1,240 | 7 | 37 HRC | 2.2 % IACS |
Full HardThis page heavily cold rolled strip | Maximum as-rolled strength for springs and flat gaskets; brittle in bending and prone to distortion on welding. | 1,010 | 1,310 | 4 | 40 HRC | 2.2 % IACS |
What is S31730 Full Hard?
S31730 Full Hard is S31730 supplied in the Full Hard condition — maximum as-rolled strength for springs and flat gaskets; brittle in bending and prone to distortion on welding. S31730 Full Hard has a yield strength of 1,010 MPa (146 ksi) and a tensile strength of 1,310 MPa (190 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 4% and the elastic modulus is 200 GPa (29 Msi). S31730 Full Hard has a density of 8 g/cm³ (0.289 lb/in³), heavier than 92% of stainless steel grades. It melts at 1,375°C (2,507 °F). Annealed is the default condition FabDigit quotes; Full Hard is available on request or by drawing note.
Advantages
- High strength — 1,010 MPa (146 ksi), better than 98% of stainless steel grades
Limitations
- Limited ductility — 4%, worse than 100% of stainless steel grades
- Limited formability — 12/100, worse than 93% of stainless steel grades
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
- Difficult to machine — 25/100, worse than 88% of stainless steel grades
- Low fracture toughness — 85 MPa·√m (77.4 ksi·√in), worse than 77% of stainless steel grades
S31730 Full Hard properties
Typical room-temperature values for S31730 Full Hard; 24 are specific to this condition. Other listed values are S31730 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
S31730 Full Hard has a density of 8 g/cm³ (0.289 lb/in³), heavier than 92% of stainless steel grades. It melts at 1,375°C (2,507 °F).
Mechanical14
S31730 Full Hard has a yield strength of 1,010 MPa (146 ksi) and a tensile strength of 1,310 MPa (190 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 4% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S31730 Full Hard is rated for continuous service to 300°C (572 °F). It conducts heat at 14.7 W/m·K (8.49 BTU/hr·ft·°F), worse than 69% of stainless steel grades. Thermal expansion is 16.2 µm/m·K (9 µin/in·°F).
Electrical3
S31730 Full Hard 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 S31730 Full Hard takes about 82 MJ of energy and emits 5.4 kg of CO₂ — more than 90% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
S31730 Full Hard's machinability is poor (25/100, worse than 88% of stainless steel grades); weldability good (55/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S31730 Full Hard
Is S31730 easy to machine?
Machine like 316 but expect gummier chips from the TiC particles: rigid setups, positive-rake sharp carbide, 60–90 m/min, heavy feed and flood coolant to avoid work hardening and built-up edge.
Can S31730 be welded?
Readily welded by GTAW/GMAW/SMAW with 318 (ER318/E318) or 316L/347-type filler, no preheat and no post-weld solution anneal needed for corrosion; keep interpass below ~150 °C, back-purge with argon and use low heat input to limit distortion and hot cracking.
Can S31730 be formed, bent or molded?
Good cold formability but higher work-hardening rate than 304 — allow larger press tonnage, generous bend radii, intermediate anneals for severe draws; hot work 1150–1250 °C and always finish with solution anneal after hot forming.
What surface finishes work on S31730?
Pickle and passivate (ASTM A967) or electropolish after fabrication to restore the passive film; not anodizable, and mirror polishing can reveal titanium inclusion streaks, so specify No.4/brushed or bead-blast finishes for cosmetic parts.
S31730 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 |
|---|---|---|
| CTi-stabilized, so carbon need not be extra low | ≤ 0.08 | 0.05 |
| Si | ≤ 1 | 0.5 |
| Mn | ≤ 2 | 1.4 |
| P | ≤ 0.05 | 0.03 |
| S | ≤ 0.03 | 0.02 |
| Cr | 18 – 20 | 19 |
| Ni | 11 – 15 | 13 |
| Mogives pitting resistance above 316 | 3 – 4 | 3.5 |
| Tistabilizer, typically ≥5×C | 0.3 – 0.7 | 0.45 |
| N | ≤ 0.1 | 0.04 |
| Fe | balance | — |
S31730 Full Hard — frequently asked
What is S31730 Full Hard used for?
S31730 Full Hard is typically used for chemical reactors, high-temperature stabilized weldments, process piping and headers for hot acids, heat exchanger tube bundles, expansion joints and bellows and furnace-side ducting and flanges. In short: titanium-stabilized 316/317 grade; as-welded IGC resistance; 870 °C service limit.
What is the yield strength of S31730 Full Hard?
S31730 Full Hard has a typical yield strength of 1,010 MPa (146 ksi) and a tensile strength of 1,310 MPa (190 ksi) — stronger than 98% of stainless steel grades. Strength varies by condition: see the 9 listed tempers.
Is S31730 Full Hard easy to machine?
Not especially — machinability is rated poor (25/100, worse than 88% of stainless steel grades). Machine like 316 but expect gummier chips from the TiC particles: rigid setups, positive-rake sharp carbide, 60–90 m/min, heavy feed and flood coolant to avoid work hardening and built-up edge.
Can S31730 Full Hard be welded?
Yes — weldability is rated good (55/100). Readily welded by GTAW/GMAW/SMAW with 318 (ER318/E318) or 316L/347-type filler, no preheat and no post-weld solution anneal needed for corrosion; keep interpass below ~150 °C, back-purge with argon and use low heat input to limit distortion and hot cracking.
What surface finishes work on S31730 Full Hard?
Pickle and passivate (ASTM A967) or electropolish after fabrication to restore the passive film; not anodizable, and mirror polishing can reveal titanium inclusion streaks, so specify No.4/brushed or bead-blast finishes for cosmetic parts.
Can S31730 Full Hard be formed, bent or molded?
Good cold formability but higher work-hardening rate than 304 — allow larger press tonnage, generous bend radii, intermediate anneals for severe draws; hot work 1150–1250 °C and always finish with solution anneal after hot forming.
What is the maximum service temperature of S31730 Full Hard?
S31730 Full Hard 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.
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 A959 — Harmonized Standard Grade Compositions for Wrought Stainless Steels — ASTM International (2022)
- ASTM A666 — Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate and Flat Bar — ASTM International (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Stabilized and Mo-bearing austenitic stainless datasheets (316Ti / 317L / 317LMN) — Outokumpu / Sandvik (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.