Stainless Steel 308
AISI/SAE 308 · UNS S30800 · JIS SUS308 · also ER308
AISI 308 (S30800, SUS308, ER308) is an 18-8 austenitic stainless steel with slightly higher chromium and nickel than 304, giving extra alloy margin once the deposit is diluted by the base metal.
Reference datasheet — 308 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
308 tempers and conditions
308 is supplied in 6 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard supply condition for S30800 wire, rod and bar: maximum ductility and corrosion resistance for drawing, coiling and welding-consumable manufacture. | 260 | 585 | 55 | 150 HB | — |
308L As Welded | Choose the L version whenever the joint cannot be post-weld solution annealed and will see 425–870 °C or aggressive aqueous service (avoids sensitization). | 380 | 555 | 42 | 158 HB | 2.3 % IACS |
As-welded deposit | Property set to use when specifying weld metal for joining 304/304H or for stainless overlay on carbon steel; deposit contains 4–10 FN ferrite for hot-crack resistance. | 420 | 585 | 40 | 170 HB | 2.3 % IACS |
308H As Welded | Use for welding 304H pressure parts in creep service — the carbon floor preserves elevated-temperature strength above ~540 °C. | 430 | 600 | 38 | 172 HB | 2.3 % IACS |
Quarter hard | Occasional mill temper for strip/wire where moderate strength gain is needed without losing all bend ductility. | 515 | 860 | 15 | 25 HRC | 2.4 % IACS |
Cold drawn | Pick for straightened cut-length MIG/TIG rod and spooled wire where cast/helix control and column stiffness for wire feeding matter more than ductility. | 550 | 760 | 25 | 21 HRC | 2.4 % IACS |
What is 308?
AISI 308 (S30800, SUS308, ER308) is an 18-8 austenitic stainless steel with slightly higher chromium and nickel than 304, giving extra alloy margin once the deposit is diluted by the base metal. It is produced almost entirely as welding wire, rod and electrode for joining 304-type stainless and for weld overlay cladding, with limited strip availability. Annealed properties are about 260 MPa yield, 585 MPa tensile, 55% elongation and 150 HB (80 HRB), with service to 870 °C. Carbon is not restricted, so specify 308L where no post-weld anneal is possible and 316L filler for chloride service. 308 has a density of 8 g/cm³ (0.289 lb/in³), heavier than 92% of stainless steel grades. It melts at 1,400°C (2,552 °F). 308 has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 84% of stainless steel grades. Elongation at break is 55% and the elastic modulus is 193 GPa (28 Msi).
What is 308 used for?
- welding filler for 18-8 stainless
- weld overlay cladding
- food and chemical equipment
Advantages
- Readily welded — 92/100, better than 98% of stainless steel grades
- Ductile — tolerates forming and impact — 55%, better than 97% of stainless steel grades
- Tough — resists crack growth — 220 MPa·√m (200.2 ksi·√in), better than 97% of stainless steel grades
- Forms and bends easily — 82/100, better than 94% of stainless steel grades
- High service temperature — 870°C (1,598 °F), better than 83% of stainless steel grades
Limitations
- Low strength — 260 MPa (37.7 ksi), worse than 84% of stainless steel grades
308 properties
Typical room-temperature values for 308-ANN; bars are the position among stainless steel grades.
Physical3
308 has a density of 8 g/cm³ (0.289 lb/in³), heavier than 92% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
308 has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 84% of stainless steel grades. Elongation at break is 55% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
308 is rated for continuous service to 870°C (1,598 °F). It conducts heat at 15 W/m·K (8.67 BTU/hr·ft·°F), worse than 59% of stainless steel grades. Thermal expansion is 17.3 µm/m·K (9.61 µin/in·°F).
Electrical3
308 conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 68% of stainless steel grades.
Sustainability4
Producing a kilogram of 308 takes about 53 MJ of energy and emits 5.3 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 65%.
Manufacturability8
308's machinability is fair (40/100, better than 72% of stainless steel grades); weldability excellent (92/100); formability very good (82/100).
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. 308 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 308
Is 308 easy to machine?
Gummy and strongly work-hardening: use sharp positive-rake carbide, heavy constant feed, rigid setup and flood coolant; avoid dwelling or rubbing.
Can 308 be welded?
This is the filler grade itself — GTAW/GMAW/SAW/SMAW with Ar or Ar+2%CO₂; keep interpass below ~150 °C, target 4–10 FN ferrite (WRC-1992) and use 308L when no post-weld anneal is possible.
Can 308 be formed, bent or molded?
Excellent cold drawability and coilability in the annealed state, but high springback and rapid work hardening; interstage anneal at 1040–1120 °C followed by rapid cooling.
308 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 |
|---|---|---|
| C≤0.03 for 308L; 0.04–0.08 for 308H | ≤ 0.08 | 0.05 |
| Mn1.0–2.5 in ER308 filler per AWS A5.9 | ≤ 2 | 1.6 |
| Si0.30–0.65 in ER308 wire | ≤ 1 | 0.5 |
| P0.03 max in filler | ≤ 0.05 | — |
| S | ≤ 0.03 | — |
| Cr19.5–22.0 in ER308 filler | 19 – 21 | 20 |
| Ni9.0–11.0 in ER308 filler | 10 – 12 | 11 |
| Moresidual limit (filler spec) | ≤ 0.75 | — |
| Curesidual limit (filler spec) | ≤ 0.75 | — |
| Fe | balance | — |
What surface finishes work on 308?
Not anodizable; passivate per ASTM A967, pickle/passivate weld zones (paste or electrochemical) to restore the chromium oxide film, or electropolish for hygienic surfaces.
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 308 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S30800
- JIS
- SUS308
- Trade names
- ER308
How much does 308 cost?
308 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.
308 — frequently asked
What is 308 used for?
308 is typically used for welding filler for 18-8 stainless, weld overlay cladding and food and chemical equipment. In short: standard 304 filler grade; higher Cr-Ni than 304; wire and rod forms.
What is the yield strength of 308?
308 has a typical yield strength of 260 MPa (37.7 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 84% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is 308 easy to machine?
Not especially — machinability is rated fair (40/100, better than 72% of stainless steel grades). Gummy and strongly work-hardening: use sharp positive-rake carbide, heavy constant feed, rigid setup and flood coolant; avoid dwelling or rubbing.
Can 308 be welded?
Yes — weldability is rated excellent (92/100). This is the filler grade itself — GTAW/GMAW/SAW/SMAW with Ar or Ar+2%CO₂; keep interpass below ~150 °C, target 4–10 FN ferrite (WRC-1992) and use 308L when no post-weld anneal is possible.
What surface finishes work on 308?
Not anodizable; passivate per ASTM A967, pickle/passivate weld zones (paste or electrochemical) to restore the chromium oxide film, or electropolish for hygienic surfaces.
Can 308 be formed, bent or molded?
Excellent cold drawability and coilability in the annealed state, but high springback and rapid work hardening; interstage anneal at 1040–1120 °C followed by rapid cooling.
What is the maximum service temperature of 308?
308 is rated for continuous use to about 870°C (1,598 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 308-ANN and 308-CD?
ANN is the default condition — standard supply condition for S30800 wire, rod and bar: maximum ductility and corrosion resistance for drawing, coiling and welding-consumable manufacture. CD: pick for straightened cut-length MIG/TIG rod and spooled wire where cast/helix control and column stiffness for wire feeding matter more than ductility. Yield strength is 260 MPa in ANN versus 550 MPa in CD.
How much does 308 cost?
308 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
- AWS A5.9/A5.9M — Bare Stainless Steel Welding Electrodes and Rods (ER308/ER308L/ER308H) — AWS (2017)
- AWS A5.4/A5.4M — Stainless Steel Electrodes for SMAW (E308-XX) — AWS (2012)
- ASTM A276/A276M — Stainless Steel Bars and Shapes (UNS S30800) — ASTM (2017)
- ASTM A479/A479M — Stainless Steel Bars for Pressure Vessels — ASTM (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.6 — Welding, Brazing and Soldering (austenitic stainless filler metals) — ASM International (1993)
- ER308L / E308L consumable datasheets — Böhler Welding / Lincoln Electric / ESAB (2023)
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.