Stainless Steel 310H Annealed
Temper · default condition
AISI/SAE 310H · UNS S31009
Standard stocked condition for plate, sheet, bar and pipe; the only condition qualified for ASME elevated-temperature/creep service.
Values for the Annealed condition
Other 310H tempers and conditions
310H is listed in 6 conditions; see the grade overview at 310H.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Forged + Annealed | Pick for high-temperature flanges, valve bodies and fittings that must match 310H piping in creep strength. | 260 | 590 | 42 | 165 HB | 2.2 % IACS |
Hot Finished Annealed | Pick for large-diameter bar, shafts, hangers and machined furnace fixtures where creep strength matters more than surface finish. | 265 | 600 | 45 | 165 HB | 2.2 % IACS |
AnnealedDefaultThis page solution annealed ~1040–1120 °C, rapid cooled (coarse grain for creep) | Standard stocked condition for plate, sheet, bar and pipe; the only condition qualified for ASME elevated-temperature/creep service. | 275 | 620 | 45 | 160 HB | — |
Cold Finished Annealed | Pick for small-diameter machined parts needing tight tolerance and bright surface; strength slightly above hot finished bar. | 310 | 640 | 40 | 180 HB | 2.2 % IACS |
Cold drawn | Pick where higher room-temperature strength or spring-back is wanted (fasteners, wire, mesh); not for creep or long-term high-temperature duty. | 500 | 760 | 25 | 240 HB | — |
Quarter hard | Pick for stiff thin-gauge strip parts (clips, shims, springs) at room to moderate temperature; work-hardened structure recrystallizes above ~600 °C. | 585 | 860 | 15 | 24 HRC | 2.2 % IACS |
What is 310H Annealed?
310H Annealed is 310H in the Annealed temper — standard stocked condition for plate, sheet, bar and pipe; the only condition qualified for ASME elevated-temperature/creep service. 310H Annealed has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 77% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 200 GPa (29 Msi). 310H Annealed has a density of 7.98 g/cm³ (0.288 lb/in³), heavier than 85% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Advantages
- High service temperature — 1,100°C (2,012 °F), better than 96% of stainless steel grades
- Ductile — tolerates forming and impact — 45%, better than 76% of stainless steel grades
- Forms and bends easily — 68/100, better than 75% of stainless steel grades
Limitations
- High embodied carbon — 5.8 kg CO₂/kg, worse than 86% of stainless steel grades
- Low strength — 275 MPa (39.9 ksi), worse than 77% of stainless steel grades
310H Annealed properties
Typical room-temperature values for 310H Annealed; 13 are specific to this condition. Other listed values are 310H reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
310H Annealed has a density of 7.98 g/cm³ (0.288 lb/in³), heavier than 85% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical14
310H Annealed has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 77% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
310H Annealed is rated for continuous service to 1,100°C (2,012 °F). It conducts heat at 14.2 W/m·K (8.2 BTU/hr·ft·°F), worse than 76% of stainless steel grades. Thermal expansion is 15.9 µm/m·K (8.83 µin/in·°F).
Electrical3
310H Annealed conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 52% of stainless steel grades.
Sustainability4
Producing a kilogram of 310H Annealed takes about 85 MJ of energy and emits 5.8 kg of CO₂ — more than 92% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
310H Annealed's machinability is poor (28/100, worse than 79% of stainless steel grades); weldability very good (70/100); formability good (68/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 310H Annealed
Is 310H easy to machine?
Gummy and strongly work-hardening: use rigid setups, positive-rake sharp carbide, 25–50 % lower surface speed than 304, heavy feed to stay under the hardened skin, and copious high-lubricity coolant.
Can 310H be welded?
Weld with matching 310/25-20 filler (ER310/E310-15) using low heat input, stringer beads and interpass temperature below ~150 °C; fully austenitic weld metal is hot-crack sensitive and no post-weld heat treatment is normally needed, but re-solution treatment restores creep properties after heavy fabrication.
Can 310H be formed, bent or molded?
Cold forms well but needs ~50 % higher press loads and generous bend radii due to the high work-hardening rate; hot work at 1150–1200 °C and finish above 950 °C, then solution anneal at 1040–1120 °C with rapid cooling to avoid sigma/carbide networks.
What surface finishes work on 310H?
Pickle and passivate (HNO3-based) or electropolish after fabrication to restore the chromium oxide film; not anodizable — for high-temperature service leave bare, and grind/blast media must be iron-free to avoid contamination.
310H 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 |
|---|---|---|
| Ccontrolled higher carbon — source of the improved creep strength vs 310S | 0.04 – 0.1 | 0.07 |
| Cr | 24 – 26 | 25 |
| Ni | 19 – 22 | 20.5 |
| Mn | ≤ 2 | 1.5 |
| SiSi aids oxidation resistance | ≤ 1.5 | 0.6 |
| P | ≤ 0.05 | 0.03 |
| S | ≤ 0.03 | 0.01 |
| Febalance ≈ 50 % | balance | — |
310H Annealed — frequently asked
What is 310H Annealed used for?
310H Annealed is typically used for high-temperature pressure vessels, petrochemical furnace tubing and power boiler components. In short: creep-rated 310 for ASME; higher-carbon 310 variant; code pressure-part stainless.
What is the yield strength of 310H Annealed?
310H Annealed has a typical yield strength of 275 MPa (39.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 77% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is 310H Annealed easy to machine?
Not especially — machinability is rated poor (28/100, worse than 79% of stainless steel grades). Gummy and strongly work-hardening: use rigid setups, positive-rake sharp carbide, 25–50 % lower surface speed than 304, heavy feed to stay under the hardened skin, and copious high-lubricity coolant.
Can 310H Annealed be welded?
Yes — weldability is rated very good (70/100). Weld with matching 310/25-20 filler (ER310/E310-15) using low heat input, stringer beads and interpass temperature below ~150 °C; fully austenitic weld metal is hot-crack sensitive and no post-weld heat treatment is normally needed, but re-solution treatment restores creep properties after heavy fabrication.
What surface finishes work on 310H Annealed?
Pickle and passivate (HNO3-based) or electropolish after fabrication to restore the chromium oxide film; not anodizable — for high-temperature service leave bare, and grind/blast media must be iron-free to avoid contamination.
Can 310H Annealed be formed, bent or molded?
Cold forms well but needs ~50 % higher press loads and generous bend radii due to the high work-hardening rate; hot work at 1150–1200 °C and finish above 950 °C, then solution anneal at 1040–1120 °C with rapid cooling to avoid sigma/carbide networks.
What is the maximum service temperature of 310H Annealed?
310H Annealed is rated for continuous use to about 1,100°C (2,012 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 310H Annealed and 310H-CD?
Annealed is the default condition — standard stocked condition for plate, sheet, bar and pipe; the only condition qualified for ASME elevated-temperature/creep service. CD: pick where higher room-temperature strength or spring-back is wanted (fasteners, wire, mesh); not for creep or long-term high-temperature duty. Yield strength is 275 MPa in Annealed versus 500 MPa in CD.
Sources
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip — ASTM International (2023)
- ASTM A213/A213M — Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes — ASTM International (2022)
- ASTM A479/A479M and A182/A182M — Stainless Bars and Forgings for Pressure Vessels/Piping — ASTM International (2022)
- ASME BPVC Section II Part D — Properties (Metric), allowable stresses for S31009 — ASME (2023)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Heat-resisting austenitic stainless 310S/310H product data — Outokumpu / Sandvik (2022)
- GB/T 24511 / GB/T 1220 06Cr25Ni20 (2017)
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.