Stainless Steel 310H CF-Ann
Finish state
AISI/SAE 310H · UNS S31009
CF-Ann = cold Finished Annealed
Pick for small-diameter machined parts needing tight tolerance and bright surface; strength slightly above hot finished bar.
Values for the CF-Ann 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 |
AnnealedDefault 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 | — |
CF-AnnThis page 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 CF-Ann?
310H CF-Ann is 310H supplied in the CF-Ann condition — pick for small-diameter machined parts needing tight tolerance and bright surface; strength slightly above hot finished bar. 310H CF-Ann has a yield strength of 310 MPa (45 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 63% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 200 GPa (29 Msi). 310H CF-Ann 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). Annealed is the default condition FabDigit quotes; CF-Ann is available on request or by drawing note.
Advantages
- High service temperature — 1,100°C (2,012 °F), better than 96% of stainless steel grades
Limitations
- High embodied carbon — 5.8 kg CO₂/kg, worse than 86% of stainless steel grades
310H CF-Ann properties
Typical room-temperature values for 310H CF-Ann; 22 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 CF-Ann 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 CF-Ann has a yield strength of 310 MPa (45 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 63% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
310H CF-Ann 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 CF-Ann 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 CF-Ann 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 CF-Ann's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability good (69/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 310H CF-Ann
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 CF-Ann — frequently asked
What is 310H CF-Ann used for?
310H CF-Ann 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 CF-Ann?
310H CF-Ann has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 63% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is 310H CF-Ann easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% 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 CF-Ann be welded?
Yes — weldability is rated good (69/100). 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 CF-Ann?
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 CF-Ann 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 CF-Ann?
310H CF-Ann 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.