Stainless Steel ER308Si-SA (Solution Annealed)
Heat-treated state
UNS S30880
Specify when the whole fabrication is solution treated at 1040–1100 °C and water quenched: δ-ferrite mostly dissolves, yield falls to 260 MPa, elongation rises to 50 % with better intergranular corrosion resistance.
Values for the SA condition
Other ER308Si tempers and conditions
ER308Si is listed in 4 conditions; see the grade overview at ER308Si.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SAThis page Solution Annealed | Specify when the whole fabrication is solution treated at 1040–1100 °C and water quenched: δ-ferrite mostly dissolves, yield falls to 260 MPa, elongation rises to 50 % with better intergranular corrosion resistance. | 260 | 550 | 50 | 150 HB | 2.4 % IACS |
As Welded (SAW) | Use φ2.0–4.0 mm submerged-arc wire for thick-wall vessels and overlay; high heat input leaves 380 MPa yield and 36 % elongation, with ferrite level and toughness set by the neutral flux pairing. | 380 | 580 | 36 | 172 HB | 2.4 % IACS |
As Welded (GTAW) | Pick φ1.6–3.2 mm, 1000 mm straight lengths for pure-argon TIG root runs and thin sheet; low heat input and less oxidation give 40 % elongation, slightly tougher than the MIG deposit. | 390 | 590 | 40 | 165 HB | 2.4 % IACS |
AWDefault As-welded deposit | Choose as the standard supply and qualification state: φ0.8–1.6 mm spooled solid wire for MIG/MAG under Ar+2%O₂ or Ar+CO₂, used as welded at 400 MPa yield and 600 MPa tensile. | 400 | 600 | 38 | 175 HB | 2.4 % IACS |
What is ER308Si-SA?
ER308Si-SA is ER308Si heat treated to SA — specify when the whole fabrication is solution treated at 1040–1100 °C and water quenched: δ-ferrite mostly dissolves, yield falls to 260 MPa, elongation rises to 50 % with better intergranular corrosion resistance. ER308Si-SA has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 84% of stainless steel grades. Elongation at break is 50% and the elastic modulus is 195 GPa (28.3 Msi). ER308Si-SA has a density of 7.95 g/cm³ (0.287 lb/in³), heavier than 81% of stainless steel grades. It melts at 1,400°C (2,552 °F). AW is the default condition FabDigit quotes; SA is available on request or by drawing note.
Advantages
- Readily welded — 95/100, better than 99% of stainless steel grades
- Tough — resists crack growth — 220 MPa·√m (200.2 ksi·√in), better than 97% of stainless steel grades
- Ductile — tolerates forming and impact — 50%, better than 90% of stainless steel grades
- Forms and bends easily — 75/100, better than 87% of stainless steel grades
- Easy to machine — 45/100, better than 84% of stainless steel grades
Limitations
- Low strength — 260 MPa (37.7 ksi), worse than 84% of stainless steel grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 77% of stainless steel grades
ER308Si-SA properties
Typical room-temperature values for ER308Si-SA; 23 are specific to this condition. Other listed values are ER308Si reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
ER308Si-SA has a density of 7.95 g/cm³ (0.287 lb/in³), heavier than 81% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
ER308Si-SA has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 84% of stainless steel grades. Elongation at break is 50% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
ER308Si-SA is rated for continuous service to 760°C (1,400 °F). It conducts heat at 16 W/m·K (9.24 BTU/hr·ft·°F), better than 58% of stainless steel grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
ER308Si-SA conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), better than 73% of stainless steel grades.
Sustainability4
Producing a kilogram of ER308Si-SA takes about 55 MJ of energy and emits 5.5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
ER308Si-SA's machinability is fair (45/100, better than 84% of stainless steel grades); weldability excellent (95/100); formability very good (75/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ER308Si-SA
Is ER308Si easy to machine?
Weld metal machines much like 304: it work-hardens quickly, so use sharp cutting edges, heavy feed, low speed and ample coolant, and prevent the tool from rubbing or skating on the bead.
Can ER308Si be welded?
For MIG use Ar + 2 % O₂ or Ar + 1–3 % CO₂ (higher CO₂ increases carbon pickup); for TIG use pure argon with an argon back-purge. Hold interpass temperature at 150 °C or below and control ferrite to 5–10 FN to prevent hot cracking.
Can ER308Si be formed, bent or molded?
Forming does not apply to a filler metal. The wire is supplied bright cold-drawn or copper-coated; keep it dry and free of oil during feeding to avoid porosity.
What surface finishes work on ER308Si?
Pickle and passivate after welding, or use a stainless-only wire brush, to remove heat tint and the chromium-depleted layer. High-silicon beads polish well, but ferrite bands can appear as streaks after electropolishing.
ER308Si 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 | ≤ 0.08 | 0.05 |
| Cr | 19.5 – 22 | 20.5 |
| Ni | 9 – 11 | 10 |
| Mn | 1 – 2.5 | 1.8 |
| Sihigh-Si design; improves wetting and flow | 0.65 – 1 | 0.85 |
| Moresidual element | ≤ 0.75 | — |
| Cuincluded when copper-coated | ≤ 0.75 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
ER308Si-SA — frequently asked
What is ER308Si-SA used for?
ER308Si-SA is typically used for short-circuit GMAW of 304 stainless, thin-gauge stainless sheet welding, stainless enclosures and cabinets, kitchen and food equipment fabrication, robotic MIG welding of 304 assemblies and tank and hopper seam welds. In short: best-wetting 308 wire; thin-sheet GMAW filler; silicon slag needs brushing.
What is the yield strength of ER308Si-SA?
ER308Si-SA has a typical yield strength of 260 MPa (37.7 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 84% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is ER308Si-SA easy to machine?
Reasonably — machinability is rated fair (45/100, better than 84% of stainless steel grades). Weld metal machines much like 304: it work-hardens quickly, so use sharp cutting edges, heavy feed, low speed and ample coolant, and prevent the tool from rubbing or skating on the bead.
Can ER308Si-SA be welded?
Yes — weldability is rated excellent (95/100). For MIG use Ar + 2 % O₂ or Ar + 1–3 % CO₂ (higher CO₂ increases carbon pickup); for TIG use pure argon with an argon back-purge. Hold interpass temperature at 150 °C or below and control ferrite to 5–10 FN to prevent hot cracking.
What surface finishes work on ER308Si-SA?
Pickle and passivate after welding, or use a stainless-only wire brush, to remove heat tint and the chromium-depleted layer. High-silicon beads polish well, but ferrite bands can appear as streaks after electropolishing.
Can ER308Si-SA be formed, bent or molded?
Forming does not apply to a filler metal. The wire is supplied bright cold-drawn or copper-coated; keep it dry and free of oil during feeding to avoid porosity.
What is the maximum service temperature of ER308Si-SA?
ER308Si-SA is rated for continuous use to about 760°C (1,400 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ER308Si-AW and ER308Si-SA?
AW is the default condition — choose as the standard supply and qualification state: φ0.8–1.6 mm spooled solid wire for MIG/MAG under Ar+2%O₂ or Ar+CO₂, used as welded at 400 MPa yield and 600 MPa tensile. SA: specify when the whole fabrication is solution treated at 1040–1100 °C and water quenched: δ-ferrite mostly dissolves, yield falls to 260 MPa, elongation rises to 50 % with better intergranular corrosion resistance. Yield strength is 400 MPa in AW versus 260 MPa in SA.
Sources
- AWS A5.9/A5.9M — Bare Stainless Steel Welding Electrodes and Rods — AWS (2017)
- ASME BPVC Section II Part C, SFA-5.9 — ASME (2023)
- ASM Handbook Vol.6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
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.