Stainless Steel 309H
AISI/SAE 309H · UNS S30909
AISI 309H (S30909) is a controlled higher-carbon (0.04–0.10%) version of the 23Cr-13Ni austenitic stainless family, the carbon raising creep and stress-rupture strength for ASME pressure-part service.
Reference datasheet — 309H 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 ANN condition
309H tempers and conditions
309H is supplied in 3 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Forged and solution annealed (ASTM A473 / A182-type parts) | Flanges, rolls, tube sheets and heavy furnace fittings forged then re-annealed to restore corrosion/creep behaviour. | 290 | 585 | 42 | 165 HB | 2.2 % IACS |
ANNDefault Annealed | Standard stocked condition for plate, sheet, bar and pipe; required for ASME high-temperature (creep) service. | 310 | 620 | 45 | 155 HB | 2.2 % IACS |
Cold drawn | Choose for tighter tolerance and better surface on small-diameter bar; strength raised, ductility reduced. | 550 | 760 | 30 | 20 HRC | 2.2 % IACS |
Supply forms, finishes and certifications
Ways 309H is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
HF-ANN-BAR | Hot finished, annealed bar / billet | Supply form |
Tube-Ann | Seamless/welded tube & pipe, solution annealed | Supply form |
CRA-2B | Cold rolled, annealed and pickled sheet/strip, 2B finish | Surface finish |
HRAP | Hot rolled, annealed and pickled plate | Surface finish |
What is 309H?
AISI 309H (S30909) is a controlled higher-carbon (0.04–0.10%) version of the 23Cr-13Ni austenitic stainless family, the carbon raising creep and stress-rupture strength for ASME pressure-part service. It is supplied as annealed plate, sheet, hot-finished and cold-drawn bar, forgings and tube for boiler and furnace parts working up to 1095 °C. Annealed values are about 310 MPa yield, 620 MPa tensile, 45% elongation and 155 HB (83 HRB), with good hot workability. The higher carbon makes it prone to sensitization in wet corrosive service — use 309Cb or 309HCb where that matters, or 310H for more oxidation margin. 309H has a density of 7.89 g/cm³ (0.285 lb/in³), heavier than 60% of stainless steel grades. It melts at 1,400°C (2,552 °F). 309H has a yield strength of 310 MPa (45 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 63% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 200 GPa (29 Msi).
What is 309H used for?
- High-temperature pressure vessels
- Boiler and superheater components
- Furnace retorts and muffles
- Hot-gas ducting and breeching
- Refinery heater internals
- Heat treatment fixtures
- Thermowells and burner hardware
Advantages
- High service temperature — 1,095°C (2,003 °F), better than 94% of stainless steel grades
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 86% of stainless steel grades
- Readily welded — 80/100, better than 80% of stainless steel grades
- Forms and bends easily — 70/100, better than 79% of stainless steel grades
- Ductile — tolerates forming and impact — 45%, better than 76% of stainless steel grades
309H properties
Typical room-temperature values for 309H-ANN; bars are the position among stainless steel grades.
Physical3
309H has a density of 7.89 g/cm³ (0.285 lb/in³), heavier than 60% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
309H has a yield strength of 310 MPa (45 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 63% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
309H is rated for continuous service to 1,095°C (2,003 °F). It conducts heat at 15.6 W/m·K (9.01 BTU/hr·ft·°F), better than 55% of stainless steel grades. Thermal expansion is 14.9 µm/m·K (8.28 µin/in·°F).
Electrical3
309H conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 63% of stainless steel grades.
Sustainability4
Producing a kilogram of 309H takes about 55 MJ of energy and emits 5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 60%.
Manufacturability8
309H's machinability is fair (35/100, better than 51% of stainless steel grades); weldability very good (80/100); formability very good (70/100).
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. 309H is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 309H
Is 309H easy to machine?
Machine like 310S — rigid setup, sharp positive-rake carbide, heavy constant feed to cut under the work-hardened layer, 25–60 m/min with flood coolant; ~40% of AISI 1212.
Can 309H be welded?
Readily welded by GTAW/GMAW/SMAW with ER309/E309 (or 309H for matching creep strength); no preheat, interpass <150 °C, no PWHT normally required, but re-solution-anneal restores ductility after long high-temperature service.
Can 309H be formed, bent or molded?
Good hot workability at 1150–1200 °C; cold forms well but work-hardens fast — allow larger bend radii, higher press loads and intermediate anneals at 1040–1100 °C followed by rapid cooling.
309H 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 for creep strength (H grade) | 0.04 – 0.1 | 0.07 |
| Mn | ≤ 2 | 1.5 |
| Si | ≤ 1 | 0.6 |
| P | ≤ 0.05 | 0.03 |
| S | ≤ 0.03 | 0.01 |
| Cr | 22 – 24 | 23 |
| Ni | 12 – 15 | 13.5 |
| N | ≤ 0.1 | 0.04 |
| Fe | balance | — |
What surface finishes work on 309H?
Not anodizable; descale by pickling (HNO₃/HF) or blasting, then passivate per ASTM A967; can be ground and polished to No.4/No.8, and forms a protective Cr₂O₃ scale in service.
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
Equivalent designations
Standards and trade names that resolve to Stainless Steel 309H in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S30909
How much does 309H cost?
309H 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.
309H — frequently asked
What is 309H used for?
309H is typically used for high-temperature pressure vessels, boiler and superheater components, furnace retorts and muffles, hot-gas ducting and breeching, refinery heater internals and heat treatment fixtures. In short: creep-strength 309 variant; ASME pressure-part grade; 1095 °C service ceiling.
What is the yield strength of 309H?
309H has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 63% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is 309H easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of stainless steel grades). Machine like 310S — rigid setup, sharp positive-rake carbide, heavy constant feed to cut under the work-hardened layer, 25–60 m/min with flood coolant; ~40% of AISI 1212.
Can 309H be welded?
Yes — weldability is rated very good (80/100). Readily welded by GTAW/GMAW/SMAW with ER309/E309 (or 309H for matching creep strength); no preheat, interpass <150 °C, no PWHT normally required, but re-solution-anneal restores ductility after long high-temperature service.
What surface finishes work on 309H?
Not anodizable; descale by pickling (HNO₃/HF) or blasting, then passivate per ASTM A967; can be ground and polished to No.4/No.8, and forms a protective Cr₂O₃ scale in service.
Can 309H be formed, bent or molded?
Good hot workability at 1150–1200 °C; cold forms well but work-hardens fast — allow larger bend radii, higher press loads and intermediate anneals at 1040–1100 °C followed by rapid cooling.
What is the maximum service temperature of 309H?
309H is rated for continuous use to about 1,095°C (2,003 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 309H-ANN and 309H-CD?
ANN is the default condition — standard stocked condition for plate, sheet, bar and pipe; required for ASME high-temperature (creep) service. CD: choose for tighter tolerance and better surface on small-diameter bar; strength raised, ductility reduced. Yield strength is 310 MPa in ANN versus 550 MPa in CD.
How much does 309H cost?
309H 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/A479 — Stainless Steel Bars and Shapes — ASTM International (2022)
- ASTM A213/A312 — Stainless Steel Tubes and Pipe (TP309H) — ASTM International (2022)
- ASME BPVC Section II Part D — Allowable stresses, S30909 — 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)
- Type 309/309S/309H heat-resisting stainless datasheets — Outokumpu / Sandvik / NAS (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.