Stainless Steel 309 As Welded
Finish state
AISI/SAE 309 · UNS S30900 · EN 1.4828, X15CrNiSi20-12 · JIS SUS309
Properties of the all-weld-metal deposit when 309 composition is used as filler for dissimilar-metal, clad-steel and buffer-layer welds.
Values for the As Welded condition
Other 309 tempers and conditions
309 is listed in 5 conditions; see the grade overview at 309.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot Rolled, Annealed and Pickled (plate) | Standard heavy plate condition (ASTM A240 No.1 finish) for furnace hearths, retorts and fabricated heat-resisting structures. | 285 | 590 | 45 | 170 HB | 2.2 % IACS |
mill-annealed sheet/plate condition | General mill-annealed stock (functionally equivalent to solution annealed for this grade); pick for forming and welding fabrication. | 295 | 600 | 45 | 160 HB | 2.2 % IACS |
Solution AnnealedDefault 1040–1150 °C, rapid cool | Standard stocked condition for plate, sheet, bar and pipe; maximum ductility, homogeneous austenite before high-temperature service. | 310 | 620 | 45 | 165 HB | — |
As WeldedThis page 309/309L weld metal deposit | Properties of the all-weld-metal deposit when 309 composition is used as filler for dissimilar-metal, clad-steel and buffer-layer welds. | 400 | 590 | 35 | 190 HB | 2.2 % IACS |
Cold Drawn Bar (lightly cold worked) | Choose for bar/shaft stock needing closer tolerance, better surface and higher strength than annealed; ductility and formability reduced. | 450 | 725 | 30 | 200 HB | — |
What is 309 As Welded?
309 As Welded is 309 supplied in the As Welded condition — properties of the all-weld-metal deposit when 309 composition is used as filler for dissimilar-metal, clad-steel and buffer-layer welds. 309 As Welded has a yield strength of 400 MPa (58 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 57% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 197 GPa (28.6 Msi). 309 As Welded has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F). Solution Annealed is the default condition FabDigit quotes; As Welded is available on request or by drawing note.
Limitations
- High embodied carbon — 6 kg CO₂/kg, worse than 88% of stainless steel grades
309 As Welded properties
Typical room-temperature values for 309 As Welded; 22 are specific to this condition. Other listed values are 309 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
309 As Welded has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
309 As Welded has a yield strength of 400 MPa (58 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 57% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 197 GPa (28.6 Msi).
Thermal6
309 As Welded is rated for continuous service to 800°C (1,472 °F). It conducts heat at 15.5 W/m·K (8.96 BTU/hr·ft·°F), better than 53% of stainless steel grades. Thermal expansion is 14.9 µm/m·K (8.28 µin/in·°F).
Electrical3
309 As Welded conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (63/100), better than 53% of stainless steel grades.
Sustainability4
Producing a kilogram of 309 As Welded takes about 56 MJ of energy and emits 6 kg of CO₂ — more than 59% of stainless steel grades. Typical recycled content is 60%.
Manufacturability8
309 As Welded's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability good (68/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 309 As Welded
Is 309 easy to machine?
Gummy and strongly work-hardening: run rigid setups, positive-rake sharp carbide, 20–30 % lower speed than 304, heavy feed and flood coolant to avoid glazing and work-hardened skins.
Can 309 be welded?
Readily welded by GTAW/GMAW/SMAW with 309/309L filler; no preheat needed, keep interpass low, limit heat input and avoid 600–900 °C holds to reduce sigma-phase and carbide embrittlement.
Can 309 be formed, bent or molded?
Cold forms like 304 but needs about 20 % more power and generous bend radii due to the high work-hardening rate; hot work at 1150–1200 °C followed by solution anneal at 1040–1150 °C.
What surface finishes work on 309?
Pickle and passivate after hot working or welding to restore the chromium oxide film; can be ground, brushed, electropolished or mirror-polished — not anodizable.
309 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 |
|---|---|---|
| C309S (S30908) limits C to 0.08 max | ≤ 0.2 | 0.12 |
| SiEN 1.4828 runs 1.5–2.5 % Si for extra scaling resistance | ≤ 1 | 0.6 |
| Mn | ≤ 2 | 1.4 |
| P | ≤ 0.05 | — |
| S | ≤ 0.03 | — |
| Cr | 22 – 24 | 23 |
| Ni | 12 – 15 | 13.5 |
| Moresidual only in some specs | ≤ 0.75 | — |
| Fe | balance | — |
309 As Welded — frequently asked
What is 309 As Welded used for?
309 As Welded is typically used for furnace parts and muffles, heat-treatment fixtures and baskets, radiant tubes and burner components, kiln and furnace linings, boiler baffles and supports and high-temperature exhaust systems. In short: high-temperature heat expert.
What is the yield strength of 309 As Welded?
309 As Welded has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 57% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 309 As Welded easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Gummy and strongly work-hardening: run rigid setups, positive-rake sharp carbide, 20–30 % lower speed than 304, heavy feed and flood coolant to avoid glazing and work-hardened skins.
Can 309 As Welded be welded?
Yes — weldability is rated good (68/100). Readily welded by GTAW/GMAW/SMAW with 309/309L filler; no preheat needed, keep interpass low, limit heat input and avoid 600–900 °C holds to reduce sigma-phase and carbide embrittlement.
What surface finishes work on 309 As Welded?
Pickle and passivate after hot working or welding to restore the chromium oxide film; can be ground, brushed, electropolished or mirror-polished — not anodizable.
Can 309 As Welded be formed, bent or molded?
Cold forms like 304 but needs about 20 % more power and generous bend radii due to the high work-hardening rate; hot work at 1150–1200 °C followed by solution anneal at 1040–1150 °C.
What is the maximum service temperature of 309 As Welded?
309 As Welded is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 309 As Welded?
Yes — 309 As Welded is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A240/A240M — Cr and Cr-Ni Stainless Plate, Sheet and Strip — ASTM International (2023)
- ASTM A276/A479 — Stainless Steel Bars and Shapes — ASTM International (2022)
- EN 10095 — Heat resisting steels and nickel alloys (1.4828) — CEN (1999)
- JIS G 4304 / G 4303 (SUS309S) — JISC (2021)
- GB/T 4237 / GB/T 1220 (0Cr23Ni13, 06Cr23Ni13) — SAC (2015)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- 309/309S heat-resisting stainless datasheets (Outokumpu, AK Steel/Cleveland-Cliffs, Sandmeyer) — various producers (2022)
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.