Stainless Steel ER308Cu
ER308Cu is a copper-modified 308-type austenitic stainless filler wire from the AWS A5.9 solid-wire family, intended for joining 304/304L base metals where the Cu addition improves arc wetting and bead appearance.
Reference datasheet — ER308Cu 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 AW condition
ER308Cu tempers and conditions
ER308Cu is supplied in 4 conditions, soft to hard. AW is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Deposit solution annealed 1040–1100 °C, water quenched | For weld overlays or components solution-annealed after welding; dissolves carbides, lowers strength and ferrite, raises ductility. | 260 | 540 | 50 | 145 HB | 2.5 % IACS |
As-welded, TIG deposit | Pick for thin-section, root-pass or cosmetic welds; cleanest, lowest-oxygen deposit with the best toughness. | 370 | 585 | 43 | 155 HB | 2.5 % IACS |
AWDefault As-welded deposit | Default condition: undiluted deposit properties used for WPS/PQR strength checks. | 380 | 590 | 40 | 160 HB | — |
As-welded, MIG spray-transfer deposit | Highest-deposition condition; the Cu addition mainly benefits arc stability and bead wetting here. | 385 | 595 | 38 | 165 HB | 2.5 % IACS |
Supply forms, finishes and certifications
Ways ER308Cu is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
CD-WIRE | Cold-drawn, bright-annealed filler wire as supplied | Supply form |
AW-CRYO | As-welded, cryogenic impact qualification | Certification |
What is ER308Cu?
ER308Cu is a copper-modified 308-type austenitic stainless filler wire from the AWS A5.9 solid-wire family, intended for joining 304/304L base metals where the Cu addition improves arc wetting and bead appearance. It is supplied as spooled solid wire for GMAW and as cut lengths for GTAW; as-welded deposits run about 380 MPa yield, 590 MPa tensile, 40 % elongation and 160 HB (85 HRB). Maximum service temperature is 760 °C and the corrosion resistance score is 63, but this is not a low-carbon (L) type, so sensitization limits it in wet corrosive service. ER308LSi is the more widely stocked alternative when wetting is the only requirement. ER308Cu 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). ER308Cu has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 52% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 195 GPa (28.3 Msi).
What is ER308Cu used for?
- Cosmetic-grade stainless GMAW welding
- 304/304L sheet and tube fabrication
- Architectural stainless railings and trim
- Food and beverage equipment weldments
- Tank and vessel seam welding
- Decorative stainless panel joints
- Cryogenic 304L weldments
Advantages
- Readily welded — 92/100, better than 98% of stainless steel grades
ER308Cu properties
Typical room-temperature values for ER308Cu-AW; bars are the position among stainless steel grades.
Physical3
ER308Cu 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).
Mechanical14
ER308Cu has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 52% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
ER308Cu is rated for continuous service to 760°C (1,400 °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 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
ER308Cu conducts electricity at 2.5 % IACS, better than 75% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (63/100), better than 53% of stainless steel grades.
Sustainability4
Producing a kilogram of ER308Cu takes about 53 MJ of energy and emits 4.6 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
ER308Cu's machinability is fair (38/100, better than 63% of stainless steel grades); weldability excellent (92/100); formability good (60/100).
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. ER308Cu is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ER308Cu
Is ER308Cu easy to machine?
Weld deposit machines like Type 304 — work-hardens rapidly, so use sharp positive-rake carbide, heavy feed, rigid setup and flood coolant; expect ~45 % of AISI 1212.
Can ER308Cu be welded?
This IS the filler: run GMAW with Ar+1–2 % O₂ or Ar+2 % CO₂ (avoid high-CO₂ mixes to limit carbon pickup), GTAW with pure Ar and Ar backing; keep interpass below ~150 °C and heat input moderate to hold 5–12 FN and prevent hot cracking.
Can ER308Cu be formed, bent or molded?
Deposit is fully austenitic-plus-ferrite and bends readily; the drawn wire itself is heavily cold-worked and should be kept on a proper cast/helix to avoid feeding problems.
ER308Cu 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 |
|---|---|---|
| CER308 base level; not a low-carbon (L) grade | ≤ 0.08 | 0.05 |
| Cr | 19.5 – 22 | 20.5 |
| Ni | 9 – 11 | 10 |
| Cudeliberate addition — the defining feature vs ER308 (which caps Cu at 0.75) | 0.75 – 1.75 | 1.2 |
| Mn | 1 – 2.5 | 1.8 |
| Sisome suppliers offer a Si-raised 308SiCu version at 0.65–1.00 | 0.3 – 0.65 | 0.5 |
| Moresidual | ≤ 0.75 | 0.2 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Fe | balance |
What surface finishes work on ER308Cu?
Pickle and passivate (nitric-HF paste or bath) or mechanically blend to remove heat tint; Cu enrichment can leave a slight coppery bead tint that pickling removes — do not use carbon-steel brushes.
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
How much does ER308Cu cost?
ER308Cu 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.
ER308Cu — frequently asked
What is ER308Cu used for?
ER308Cu is typically used for cosmetic-grade stainless GMAW welding, 304/304L sheet and tube fabrication, architectural stainless railings and trim, food and beverage equipment weldments, tank and vessel seam welding and decorative stainless panel joints. In short: better wetting than ER308; cosmetic bead appearance; general 304-family filler.
What is the yield strength of ER308Cu?
ER308Cu has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 52% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is ER308Cu easy to machine?
Not especially — machinability is rated fair (38/100, better than 63% of stainless steel grades). Weld deposit machines like Type 304 — work-hardens rapidly, so use sharp positive-rake carbide, heavy feed, rigid setup and flood coolant; expect ~45 % of AISI 1212.
Can ER308Cu be welded?
Yes — weldability is rated excellent (92/100). This IS the filler: run GMAW with Ar+1–2 % O₂ or Ar+2 % CO₂ (avoid high-CO₂ mixes to limit carbon pickup), GTAW with pure Ar and Ar backing; keep interpass below ~150 °C and heat input moderate to hold 5–12 FN and prevent hot cracking.
What surface finishes work on ER308Cu?
Pickle and passivate (nitric-HF paste or bath) or mechanically blend to remove heat tint; Cu enrichment can leave a slight coppery bead tint that pickling removes — do not use carbon-steel brushes.
Can ER308Cu be formed, bent or molded?
Deposit is fully austenitic-plus-ferrite and bends readily; the drawn wire itself is heavily cold-worked and should be kept on a proper cast/helix to avoid feeding problems.
What is the maximum service temperature of ER308Cu?
ER308Cu 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 ER308Cu-AW and ER308Cu-SA?
AW is the default condition — default condition: undiluted deposit properties used for WPS/PQR strength checks. SA: for weld overlays or components solution-annealed after welding; dissolves carbides, lowers strength and ferrite, raises ductility. Yield strength is 380 MPa in AW versus 260 MPa in SA.
How much does ER308Cu cost?
ER308Cu 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 — American Welding Society (2017)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
- Stainless solid wire all-weld-metal datasheets (ER308/ER308Si class) — Kobelco / 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.