Stainless Steel ER309LSi
UNS S30983 · EN 23 12 L Si
ER309LSi is the low-carbon, high-silicon version of the 23Cr-12Ni austenitic filler family (UNS S30983, 23 12 L Si), with silicon added to improve arc stability and bead wetting in GMAW.
Reference datasheet — ER309LSi 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
ER309LSi tempers and conditions
ER309LSi 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 |
|---|---|---|---|---|---|---|
Stress relieved | Condition after PWHT of the carbon/low-alloy side; strength drops slightly and sigma/carbide risk rises above 550 °C. | 360 | 560 | 36 | 175 HB | 2.3 % IACS |
As-welded deposit with neutral/basic submerged-arc flux | Use for high-deposition overlay cladding of carbon-steel vessels; flux choice controls ferrite and Si pickup. | 370 | 560 | 35 | 175 HB | 2.2 % IACS |
As-welded deposit made with TIG rod | Pick for root passes, thin sections and cladding where the cleanest, lowest-oxygen deposit and best toughness are needed. | 390 | 580 | 40 | 180 HB | 2.2 % IACS |
AWDefault As-welded deposit | Default condition: undiluted deposit properties used for procedure qualification of dissimilar joints and buttering layers. | 400 | 590 | 38 | 185 HB | 2.2 % IACS |
Supply forms, finishes and certifications
Ways ER309LSi is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
WIRE | Solid drawn wire / spool or cut length as supplied | Supply form |
What is ER309LSi?
ER309LSi is the low-carbon, high-silicon version of the 23Cr-12Ni austenitic filler family (UNS S30983, 23 12 L Si), with silicon added to improve arc stability and bead wetting in GMAW. It is used for dissimilar-metal MIG welding and automated cladding, supplied as cold-drawn spooled wire and TIG rod. Typical as-welded properties are 400 MPa yield, 590 MPa tensile, 38% elongation and 185 HB (90 HRB), with service to 950 °C and a corrosion rating of 70. Where the added silicon is not needed, or for SAW with basic flux, plain ER309L is the closer match. ER309LSi 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). ER309LSi 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 38% and the elastic modulus is 200 GPa (29 Msi).
What is ER309LSi used for?
- Robotic and automated cladding of carbon steel
- Dissimilar-metal MIG welding (carbon steel to 304/316)
- Buffer layers before stainless or nickel-alloy cover passes
- Stainless-clad plate fabrication
- Transition welds in process piping
- Overlay repair of worn carbon-steel surfaces
- Heat-resisting fabrication seams
Advantages
- Readily welded — 92/100, better than 98% of stainless steel grades
- High service temperature — 950°C (1,742 °F), better than 86% of stainless steel grades
Limitations
- Hard to polish — 60/100, worse than 80% of stainless steel grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 77% of stainless steel grades
ER309LSi properties
Typical room-temperature values for ER309LSi-AW; bars are the position among stainless steel grades.
Physical3
ER309LSi 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).
Mechanical16
ER309LSi 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 38% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
ER309LSi is rated for continuous service to 950°C (1,742 °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 16 µm/m·K (8.89 µin/in·°F).
Electrical3
ER309LSi conducts electricity at 2.2 % IACS, worse than 61% 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 ER309LSi takes about 60 MJ of energy and emits 5.5 kg of CO₂ — more than 70% of stainless steel grades. Typical recycled content is 55%.
Manufacturability8
ER309LSi's machinability is fair (35/100, better than 51% of stainless steel grades); weldability excellent (92/100); formability good (55/100).
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. ER309LSi is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ER309LSi
Is ER309LSi easy to machine?
Weld deposit machines like Type 309: work-hardens fast — use sharp carbide, positive rake, heavy feed and rigid setup; expect ~45% of AISI 1212.
Can ER309LSi be welded?
Designed as filler — GMAW with Ar+1–3%O₂ or Ar+CO₂ (spray/pulse) gives smooth wetting; keep interpass ≤150 °C, heat input moderate, and aim for 8–15 FN to avoid hot cracking on high-dilution first layers.
Can ER309LSi be formed, bent or molded?
Only relevant to the wire: cold-drawn with intermediate anneals; deposit is very ductile (≈38% elongation) and tolerates cold straightening/bending of clad plate.
ER309LSi 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 |
|---|---|---|
| Clow-carbon 'L' grade | ≤ 0.03 | 0.02 |
| Cr | 23 – 25 | 24 |
| Ni | 12 – 14 | 13 |
| Mn | 1 – 2.5 | 1.8 |
| Sihigh-Si variant for arc wetting | 0.65 – 1 | 0.85 |
| Mo | ≤ 0.75 | 0.15 |
| Cu | ≤ 0.75 | 0.2 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Fe | balance |
What surface finishes work on ER309LSi?
Grind/blend with dedicated stainless abrasives, then pickle-passivate (ASTM A967) or electropolish; ferrite in the deposit can etch slightly darker than 304/316 base metal.
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 ER309LSi in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S30983
- EN / DIN / Werkstoff-Nr.
- 23 12 L Si
How much does ER309LSi cost?
ER309LSi is a high-cost stainless steel ($$$$), pricier than about 78% 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.
ER309LSi — frequently asked
What is ER309LSi used for?
ER309LSi is typically used for robotic and automated cladding of carbon steel, dissimilar-metal MIG welding (carbon steel to 304/316), buffer layers before stainless or nickel-alloy cover passes, stainless-clad plate fabrication, transition welds in process piping and overlay repair of worn carbon-steel surfaces. In short: best-wetting 309 filler; low-carbon dissimilar-metal wire; built for spray-transfer GMAW.
What is the yield strength of ER309LSi?
ER309LSi 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 4 listed tempers.
Is ER309LSi easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of stainless steel grades). Weld deposit machines like Type 309: work-hardens fast — use sharp carbide, positive rake, heavy feed and rigid setup; expect ~45% of AISI 1212.
Can ER309LSi be welded?
Yes — weldability is rated excellent (92/100). Designed as filler — GMAW with Ar+1–3%O₂ or Ar+CO₂ (spray/pulse) gives smooth wetting; keep interpass ≤150 °C, heat input moderate, and aim for 8–15 FN to avoid hot cracking on high-dilution first layers.
What surface finishes work on ER309LSi?
Grind/blend with dedicated stainless abrasives, then pickle-passivate (ASTM A967) or electropolish; ferrite in the deposit can etch slightly darker than 304/316 base metal.
Can ER309LSi be formed, bent or molded?
Only relevant to the wire: cold-drawn with intermediate anneals; deposit is very ductile (≈38% elongation) and tolerates cold straightening/bending of clad plate.
What is the maximum service temperature of ER309LSi?
ER309LSi is rated for continuous use to about 950°C (1,742 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ER309LSi-AW and ER309LSi-SR?
AW is the default condition — default condition: undiluted deposit properties used for procedure qualification of dissimilar joints and buttering layers. SR: condition after PWHT of the carbon/low-alloy side; strength drops slightly and sigma/carbide risk rises above 550 °C. Yield strength is 400 MPa in AW versus 360 MPa in SR.
How much does ER309LSi cost?
ER309LSi is a high-cost stainless steel ($$$$), pricier than about 78% 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 — AWS (2017)
- EN ISO 14343 (23 12 L Si) — ISO (2017)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels — ASM International (1990)
- 309LSi solid wire all-weld-metal data (Böhler/ESAB/Lincoln class datasheets) — voestalpine Böhler Welding / ESAB / Lincoln Electric (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.