Stainless Steel ER320-SA (Solution Annealed)
Heat-treated state
UNS N08021
Pick when the fabricated Alloy 20 weldment is post-weld solution annealed for maximum acid corrosion resistance and ductility.
Values for the SA condition
Other ER320 tempers and conditions
ER320 is listed in 2 conditions; see the grade overview at ER320.
- SA
- AW
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SAThis page Solution Annealed | Pick when the fabricated Alloy 20 weldment is post-weld solution annealed for maximum acid corrosion resistance and ductility. | 300 | 560 | 42 | 160 HB | 1.6 % IACS |
AWDefault As-welded deposit | Default condition for filler metal: properties of the undiluted as-deposited weld metal. | 380 | 585 | 34 | 180 HB | 1.6 % IACS |
What is ER320-SA?
ER320-SA is ER320 heat treated to SA — pick when the fabricated Alloy 20 weldment is post-weld solution annealed for maximum acid corrosion resistance and ductility. ER320-SA has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 42% and the elastic modulus is 193 GPa (28 Msi). ER320-SA has a density of 8.02 g/cm³ (0.29 lb/in³), heavier than 97% of stainless steel grades. It melts at 1,370°C (2,498 °F). AW is the default condition FabDigit quotes; SA is available on request or by drawing note.
Advantages
- Good corrosion resistance — 85/100, better than 92% of stainless steel grades
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 86% of stainless steel grades
- Forms and bends easily — 72/100, better than 84% of stainless steel grades
Limitations
- Low electrical conductivity — 1.6 % IACS, worse than 99% of stainless steel grades
- High embodied carbon — 8.5 kg CO₂/kg, worse than 99% of stainless steel grades
- Poor heat conductor — 12.6 W/m·K (7.28 BTU/hr·ft·°F), worse than 88% of stainless steel grades
ER320-SA properties
Typical room-temperature values for ER320-SA; 22 are specific to this condition. Other listed values are ER320 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
ER320-SA has a density of 8.02 g/cm³ (0.29 lb/in³), heavier than 97% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Mechanical16
ER320-SA has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 42% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
ER320-SA is rated for continuous service to 500°C (932 °F). It conducts heat at 12.6 W/m·K (7.28 BTU/hr·ft·°F), worse than 88% of stainless steel grades. Thermal expansion is 14.8 µm/m·K (8.22 µin/in·°F).
Electrical3
ER320-SA conducts electricity at 1.6 % IACS, worse than 99% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 92% of stainless steel grades.
Sustainability4
Producing a kilogram of ER320-SA takes about 95 MJ of energy and emits 8.5 kg of CO₂ — more than 96% of stainless steel grades. Typical recycled content is 30%.
Manufacturability8
ER320-SA's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability very good (75/100); formability very good (72/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ER320-SA
Is ER320 easy to machine?
Weld deposit machines like a gummy high-nickel austenitic: sharp positive-rake carbide, low speed, heavy positive feed, flood coolant, no dwelling.
Can ER320 be welded?
GTAW/GMAW/SAW with low heat input, interpass ≤ 100–150 °C and stringer beads; argon (or Ar+He) shielding and back purge; use ER320LR for restrained multipass joints to avoid hot cracking.
Can ER320 be formed, bent or molded?
Supplied as drawn wire; work-hardens quickly, so redrawing needs intermediate anneals — not a wrought structural product form.
What surface finishes work on ER320?
Pickle and passivate weld areas (nitric/HF paste) to restore the Cr-Mo-Cu passive film; do not anodize; grind heat tint fully before acid service.
ER320 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 |
|---|---|---|
| CER320LR: 0.025 max | ≤ 0.07 | 0.05 |
| Cr | 19 – 21 | 20 |
| Ni | 32 – 36 | 34 |
| Mo | 2 – 3 | 2.5 |
| Cu | 3 – 4 | 3.5 |
| NbCb+Ta, 8×C min to 1.00 max; ER320LR 0.15–0.35 | 0.4 – 1 | 0.7 |
| MnER320LR: 1.50–2.00 | ≤ 2.5 | 1.8 |
| SiER320LR: 0.15 max | ≤ 0.6 | 0.35 |
| PER320LR: 0.015 max | ≤ 0.04 | 0.02 |
| SER320LR: 0.015 max | ≤ 0.03 | 0.01 |
| Febalance, ~36 % | balance | — |
ER320-SA — frequently asked
What is ER320-SA used for?
ER320-SA is typically used for sulfuric acid equipment, chemical processing tanks, alloy 20 pump and valve bodies, pickling line tanks and piping, acid mixers and agitator shafts and corrosion-resistant overlay on carbon steel. In short: alloy 20 filler wire; built for sulfuric acid; highest corrosion rating here.
What is the yield strength of ER320-SA?
ER320-SA has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 68% of stainless steel grades. Strength varies by condition: see the 2 listed tempers.
Is ER320-SA easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Weld deposit machines like a gummy high-nickel austenitic: sharp positive-rake carbide, low speed, heavy positive feed, flood coolant, no dwelling.
Can ER320-SA be welded?
Yes — weldability is rated very good (75/100). GTAW/GMAW/SAW with low heat input, interpass ≤ 100–150 °C and stringer beads; argon (or Ar+He) shielding and back purge; use ER320LR for restrained multipass joints to avoid hot cracking.
What surface finishes work on ER320-SA?
Pickle and passivate weld areas (nitric/HF paste) to restore the Cr-Mo-Cu passive film; do not anodize; grind heat tint fully before acid service.
Can ER320-SA be formed, bent or molded?
Supplied as drawn wire; work-hardens quickly, so redrawing needs intermediate anneals — not a wrought structural product form.
What is the maximum service temperature of ER320-SA?
ER320-SA is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ER320-AW and ER320-SA?
AW is the default condition — default condition for filler metal: properties of the undiluted as-deposited weld metal. SA: pick when the fabricated Alloy 20 weldment is post-weld solution annealed for maximum acid corrosion resistance and ductility. Yield strength is 380 MPa in AW versus 300 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)
- Alloy 20 / 20Cb-3 physical and corrosion data — Carpenter Technology (2022)
- ER320 / ER320LR filler metal all-weld-metal properties — Special Metals Welding Products / Sandvik (2021)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
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.