Stainless Steel ER309LSi-SR (Stress relieved)
Heat-treated state
UNS S30983 · EN 23 12 L Si
Condition after PWHT of the carbon/low-alloy side; strength drops slightly and sigma/carbide risk rises above 550 °C.
Values for the SR condition
Other ER309LSi tempers and conditions
ER309LSi is listed in 4 conditions; see the grade overview at ER309LSi.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SRThis page 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 |
What is ER309LSi-SR?
ER309LSi-SR is ER309LSi heat treated to SR — condition after PWHT of the carbon/low-alloy side; strength drops slightly and sigma/carbide risk rises above 550 °C. ER309LSi-SR has a yield strength of 360 MPa (52.2 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 51% of stainless steel grades. Elongation at break is 36% and the elastic modulus is 200 GPa (29 Msi). ER309LSi-SR 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). AW is the default condition FabDigit quotes; SR is available on request or by drawing note.
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
- Low fracture toughness — 85 MPa·√m (77.4 ksi·√in), worse than 77% of stainless steel grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 77% of stainless steel grades
ER309LSi-SR properties
Typical room-temperature values for ER309LSi-SR; 22 are specific to this condition. Other listed values are ER309LSi reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
ER309LSi-SR 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-SR has a yield strength of 360 MPa (52.2 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 51% of stainless steel grades. Elongation at break is 36% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
ER309LSi-SR is rated for continuous service to 950°C (1,742 °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 µm/m·K (8.89 µin/in·°F).
Electrical3
ER309LSi-SR conducts electricity at 2.3 % IACS, better than 55% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (65/100), better than 56% of stainless steel grades.
Sustainability4
Producing a kilogram of ER309LSi-SR 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-SR's machinability is fair (38/100, better than 63% of stainless steel grades); weldability excellent (92/100); formability good (58/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ER309LSi-SR
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.
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.
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 | — |
ER309LSi-SR — frequently asked
What is ER309LSi-SR used for?
ER309LSi-SR 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-SR?
ER309LSi-SR has a typical yield strength of 360 MPa (52.2 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 51% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is ER309LSi-SR easy to machine?
Not especially — machinability is rated fair (38/100, better than 63% 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-SR 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-SR?
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-SR 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-SR?
ER309LSi-SR 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.