A182 F309 / F309H Forgings. 309 Stainless Forged Rings, Flanges, Bars and Discs
Open die and ring rolled components in 23Cr-13Ni heat resistant austenitic stainless steel, supplied to ASTM A182 Grade F309H (UNS S30909).
Grade at a glance
- ASTM A182 grade symbol
- F309H
- UNS numbers
- S30909 (309H) / S30900 (309) / S30908 (309S)
- Type
- Heat resistant austenitic chromium nickel stainless steel
- Nominal chemistry
- 23 % chromium, 13.5 % nickel
- Yield strength, min
- 205 MPa (30 ksi)
- Elongation and RA, min
- 30 % and 50 %
- Delivery condition
- Solution treated and quenched
- Oxidation resistance
- Cited to about 1038 C under non cyclic conditions and about 1010 C under frequent thermal cycling
- Forms we forge
- Seamless rolled rings, flanges, round bars, discs, sleeves, bushings, shafts, tube sheets, valve parts
- Certification
- EN 10204 3.1 or 3.2
Before you order, check the grade symbol. Published ASTM A182 grade tables list the 309 type stainless as F309H, UNS S30909. There is no plain F309 row. A182 F309 turns up constantly in enquiries, drawings and stockist listings, and we quote against it every week, but the designation that belongs on the purchase order, the certificate and the stamp is F309H.
This is not a paperwork detail. AISI 309 allows up to 0.20 % carbon. F309H sets a carbon band of 0.04 to 0.10 %, with a minimum, because creep strength at temperature depends on carbon being there. A forging supplied at 0.02 % carbon would satisfy 309 and fail F309H. If your drawing says F309, tell us the service temperature and we will confirm which chemistry the job actually needs.
Chemical composition
The table separates the forging grade from the generic wrought grade. The two are often published as one dataset, which is where most of the confusion around this material starts.
| Element | ASTM A182 F309H UNS S30909, forgings |
AISI 309 UNS S30900, wrought |
309S UNS S30908 |
EN 1.4833 X12CrNi23-13 |
|---|---|---|---|---|
| Carbon | 0.04 - 0.10 | 0.20 max | 0.08 max | 0.15 max |
| Manganese | 2.00 max | 2.00 max | 2.00 max | 2.00 max |
| Phosphorus | 0.045 max | 0.045 max | 0.045 max | 0.045 max |
| Sulfur | 0.030 max | 0.030 max | 0.030 max | 0.015 max |
| Silicon | 1.00 max | 1.00 max | 0.75 max | 1.00 max |
| Chromium | 22.0 - 24.0 | 22.0 - 24.0 | 22.0 - 24.0 | 22.0 - 24.0 |
| Nickel | 12.0 - 15.0 | 12.0 - 15.0 | 12.0 - 15.0 | 12.0 - 14.0 |
| Nitrogen | not stated in the F309H table consulted | 0.11 max | 0.11 max | 0.11 max |
| Iron | balance | balance | balance | balance |
Silicon limits vary between sources and product specifications, with 0.75 % max and 1.00 % max both published for the 309 family. Where a source gave no figure for an element, the cell says so rather than implying a limit. Confirm against the current edition of the governing standard for your order.
Mechanical properties
These are specification minimums for the solution treated condition. They are acceptance values, not design allowables and not typical results.
| Property | Metric | Imperial |
|---|---|---|
| Tensile strength, min | 515 MPa or 485 MPa | 75 ksi or 70 ksi |
| Yield strength at 0.2 % offset, min | 205 MPa | 30 ksi |
| Elongation in 50 mm or 4D, min | 30 % | 30 % |
| Reduction of area, min | 50 % | 50 % |
| Brinell hardness | Not stated for this grade in the A182 property table consulted | |
Two different minimum tensile values for F309H appear in published property tables, 515 MPa (75 ksi) and 485 MPa. Yield, elongation and reduction of area agree across those sources. We confirm the governing figure against the specification edition named on your order before we accept it. A separate point worth knowing: the 40 % minimum elongation quoted on many 309 web pages comes from plate and sheet specifications such as ASTM A240, not from the A182 forging requirement, which is 30 % with 50 % reduction of area.
Heat treatment and sigma phase
Austenitic grades in ASTM A182 are supplied solution treated and quenched. The published A182 heat treatment table gives a minimum solutioning temperature of 1040 C (1900 F) with liquid quenching for the austenitic grades listed in it, being F304, F304L, F316, F316L and F321. Check the F309H row against the current edition, since H grades can carry their own requirement.
Mill datasheets for the 309 family give a working solution annealing window of roughly 1000 to 1150 C (1832 to 2101 F) followed by rapid quenching, so that carbides go back into solution. One source gives a narrower 1120 to 1175 C window with a hold of about 30 minutes per inch of section.
The risk to manage on this grade is sigma phase. Exposure at roughly 650 to 950 C causes sigma to precipitate, which cuts room temperature ductility and impact resistance. Solution annealing at 1100 to 1150 C restores a degree of toughness. One source puts the precipitation range wider, at 649 to 1010 C. For a forging buyer this means three practical things. Do not let the part dwell in that band while cooling. Do not stress relieve inside it. Where sigma formation is expected in service, avoid heavy mechanical impact on the part at room temperature, and consider specifying impact testing.
| Operation | Condition | Notes |
|---|---|---|
| Hot forging | Roughly 950 to 1200 C | One source gives a start of 980 to 1120 C and a finish not below 980 C. Working too hot lowers hot ductility through ferrite formation. Working too cold risks sigma. Cool rapidly to black heat after forging. |
| Solution treat and quench | 1040 C (1900 F) minimum under the A182 austenitic requirement. Mill window about 1000 to 1150 C | Liquid quench or rapid cool. This is the delivery condition. |
| Avoid | Dwell at roughly 650 to 950 C | Sigma phase precipitation and loss of toughness. |
| Sigma removal | 1100 to 1150 C, then rapid cool | Restores a degree of toughness after prolonged exposure in the sigma range. |
| Hardening | Not possible | The 309 family does not harden by heat treatment. Strength is raised only by cold work, and cold work is not stable at service temperature. |
Cross reference and equivalents
The three carbon variants of the 23Cr-13Ni family get treated as interchangeable in enquiries. They are not, and the difference decides whether a loaded part creeps.
| Designation | UNS | EN and other | Carbon | When it is the right pick |
|---|---|---|---|---|
| ASTM A182 F309H | S30909 | 309H. No EN number listed in the source consulted | 0.04 - 0.10 | The A182 forging grade. Controlled carbon minimum for creep strength under sustained load at temperature. |
| AISI 309 | S30900 | 1.4833, X12CrNi23-13, SUS 309 | 0.20 max | General heat resistant bar, plate, pipe. Covered by ASTM A240, A276, A312, A479 rather than A182. |
| 309S | S30908 | 1.4833, X12CrNi23-13, SUS 309S | 0.08 max under ASTM, 0.15 max under EN 1.4833 | Welded fabrications and parts cycling through the sensitisation range. Lower carbon means less chromium carbide precipitation. |
EN 1.4833 maps to 309 and 309S, not to 309H, and no EN equivalent for 309H appears in the cross reference table consulted. So 1.4833 is not a safe drop in for F309H where creep strength governs. If a drawing cross references the two, raise it at enquiry stage. We will flag it in the quotation rather than substitute quietly. Plate and pipe are often dual certified to 309S and 309H at the same time, which is why the two get mixed up on paper.
Forged forms in F309H and 309
Everything below is produced by open die forging or ring rolling, then solution treated, machined to drawing and inspected before release.
Production capability
Ring diameter range, maximum single piece weight, press and ring mill capacity, machining envelope and normal lead time for this grade are on our capability page. Send the finished dimensions and quantity and we will confirm the job against our own equipment.
Melting, testing and certification
| Item | Standard or option | What it covers |
|---|---|---|
| Melting route | EAF with LF and VOD refining. ESR where cleanliness is critical | The route actually used is named on the certificate. |
| Ultrasonic testing | EN 10228-4 or ASTM A388 | EN 10228-4 is the part of the EN 10228 series for ultrasonic testing of austenitic and austenitic ferritic stainless steel forgings. EN 10228-3 covers ferritic and martensitic forgings, so it is the wrong call out for a 309 type grade. Worth checking on any incoming specification. Testing after final heat treatment unless agreed otherwise. |
| Liquid penetrant | ASTM E165 or EN ISO 3452 | Surface indications on machined faces and sealing surfaces. |
| Mill certificate | EN 10204 type 3.1 | Issued by the manufacturer and validated by its own independent inspection department. |
| Third party certificate | EN 10204 type 3.2 | Countersigned by an independent third party or your nominated inspector. Specify it when you place the order, it cannot be added afterwards. |
| Supplementary tests | Impact, intergranular corrosion, grain size, PMI, hardness | Quoted on request. Worth considering where service sits near the sigma range. |
Where F309H forgings are used
The 309 family earns its place where oxidation resistance at temperature matters more than room temperature strength. Published application lists centre on thermal processing equipment: annealing covers and boxes, muffles and retorts, burners and burner grids, furnace fans, doors and shafts, walking beams, radiant tubes, brazing fixtures, recuperators and heat exchangers. The same sources list waste incinerators, rotary kilns and combustion chambers, pulverised coal burners and boiler tube hangers, catalytic recovery systems in refining, fluidised bed grids and wind boxes, glass forming and melting tank parts, recovery boiler components in paper mills, thermowells, and refractory anchor bolts.
In forged form we see it most often as rolled rings and retaining rings for furnace and heat treatment equipment, hearth and burner components, tube sheets, flanges and nozzles running hot in exchangers, and valve bodies, stems and seat rings on hot service lines. Where creep strength under sustained load is the governing requirement, 309H is the variant to specify rather than 309S.
Two cautions we would rather put in writing than leave for later. Sources conflict on sulfur bearing gas. One rates the family as useful in sulfur containing atmospheres to about 1000 C because of the high chromium and moderate nickel. Another states that 309S has low resistance to oxidising sulphurous gases. Given that conflict, review the actual gas composition instead of defaulting to 309. Second, this is a high temperature grade, not a wet corrosion grade. Published data notes it is not designed for wet corrosive service, that the carbon which helps creep hurts aqueous corrosion resistance, and that it is prone to intergranular corrosion after long high temperature exposure. If your duty is aqueous chloride, look at F51, F53 or F44. We will say so in the quotation.
Frequently asked questions
Is A182 F309 a real ASTM grade?
Published ASTM A182 grade tables list the 309 type stainless as Grade F309H, UNS S30909. There is no plain F309 row. A182 F309 is shorthand in common use, but the symbol for a purchase order is F309H. Plain AISI 309 is UNS S30900, covered by ASTM A240, A276, A312 and A479 rather than by A182.
What is the chemical composition of A182 F309H?
Carbon 0.04 to 0.10 %, manganese 2.00 % max, phosphorus 0.045 % max, sulfur 0.030 % max, silicon 1.00 % max, chromium 22.0 to 24.0 %, nickel 12.0 to 15.0 %, balance iron. The carbon figure is a band with a minimum, which is the main difference from AISI 309 at 0.20 % max.
What are the minimum mechanical properties?
Yield 205 MPa (30 ksi) min, elongation 30 % min in 50 mm or 4D, reduction of area 50 % min, solution treated and quenched. Published tables differ on minimum tensile strength, with 515 MPa (75 ksi) and 485 MPa both in circulation, so confirm that figure against the specification edition named on your order.
What is the difference between 309, 309S and 309H?
Same 23Cr-13Ni base, three carbon levels. 309 (S30900) allows up to 0.20 % carbon. 309S (S30908) is held to 0.08 % max under ASTM for weldability and lower sensitisation risk. 309H (S30909, the A182 forging grade) runs a controlled 0.04 to 0.10 % band for creep strength. Plate and pipe are often dual certified to both 309S and 309H.
Which ultrasonic testing standard applies to 309 stainless forgings?
EN 10228-4 covers austenitic and austenitic ferritic stainless steel forgings. EN 10228-3 covers ferritic and martensitic forgings, so it is the wrong reference here. ASTM A388 is the usual alternative for heavy forgings. Testing normally follows final heat treatment unless agreed otherwise on the order.
Why avoid the 650 to 950 C band?
Exposure in that range precipitates sigma phase, a hard intermetallic that cuts room temperature ductility and impact resistance. Solution annealing at 1100 to 1150 C restores a degree of toughness. One source gives the range as wide as 649 to 1010 C. Where sigma is expected, avoid heavy impact on the part at room temperature.
Can 309 be used in sulfur bearing hot gas?
Sources disagree. Some rate the family as useful in sulfur containing atmospheres to about 1000 C. Another states that 309S has low resistance to oxidising sulphurous gases. Because of that conflict we treat sulfur bearing service as a case for review against the real gas composition and temperature, not an assumption.
What do you need from me to quote?
A PDF or STEP drawing is ideal. If there is no drawing yet, send outside diameter, inside diameter, height or length, quantity, grade and specification, delivery condition, NDT requirement and certificate type, 3.1 or 3.2. That is enough for a firm price. Email sales@steelforgepieces.com or call +86-189-2135-9659.
What else do you forge near this grade?
Other high temperature grades we run include 321H, 347H, 330, Incoloy 800H and 800HT and Inconel 601.
Standards referenced on this page
- ASTM A182 / A182M, forged or rolled alloy and stainless steel pipe flanges, forged fittings, valves and parts for high temperature service. Grade F309H, UNS S30909.
- ASTM A240, A276, A312, A479 for 309 and 309S plate, bar and pipe.
- ASTM A388 and EN 10228-4 for ultrasonic examination of forgings.
- ASTM E165 and EN ISO 3452 for liquid penetrant examination.
- EN 10204 for inspection documents, types 3.1 and 3.2.
- EN 10088-2, EN 10088-3 and EN 10095 for European stainless and heat resisting steel delivery conditions.
- EN 1.4833, X12CrNi23-13, and JIS SUS 309 / SUS 309S as national equivalents of 309 and 309S.
Figures on this page are for guidance. The governing document is the current edition of the relevant ASTM, ASME or EN standard together with your own project specification. Where a source gave no value, the page says so instead of filling the gap.
Related grades
Ask for a price on F309H forgings
Send a drawing, or the outside diameter, inside diameter, length and quantity. We confirm grade, forging route, heat treatment, NDT and certificate type before quoting, and we will tell you if another grade suits the service better.
Open Die Forging Factory
Zhouzhuang Town, Jiangyin City,
Jiangsu Province, China