Stainless Steel E309LMo
UNS W30923 · ASTM A5.4
E309LMo is a low-carbon 309-type austenitic stainless covered electrode to AWS A5.4 (UNS W30923) with a molybdenum addition, made in -15, -16 and -17 coatings.
Reference datasheet — E309LMo 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
E309LMo tempers and conditions
E309LMo is supplied in 5 conditions, soft to hard. AW is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Silica-boosted rutile coating, AC or DCEP | Choose for the flattest, best-wetting bead on flat/horizontal fillets and overlay; more fluid slag than -16, slightly softer arc. | 420 | 590 | 38 | 185 HB | 2.2 % IACS |
AWDefault As-welded deposit | Default condition for dissimilar joints and buttering layers; deposit used directly after welding with 8–20 FN ferrite. | 430 | 600 | 36 | 190 HB | 2.2 % IACS |
Titania (rutile) coating, AC or DCEP | Most widely stocked coating type: smooth arc, easy slag removal, AC/DC operation for general shop and site welding. | 430 | 600 | 36 | 190 HB | 2.2 % IACS |
Post-weld heat treated | Applies when the C-steel/low-alloy component must be stress relieved; expect some ferrite transformation, slight strength gain and toughness loss. | 440 | 610 | 30 | 200 HB | 2.2 % IACS |
Lime (basic) coating, DCEP only | Pick for out-of-position work and where the cleanest, lowest-hydrogen, toughest deposit is required; DC electrode positive only. | 450 | 610 | 35 | 195 HB | 2.2 % IACS |
What is E309LMo?
E309LMo is a low-carbon 309-type austenitic stainless covered electrode to AWS A5.4 (UNS W30923) with a molybdenum addition, made in -15, -16 and -17 coatings. It is the standard filler for joining or overlaying 316L stainless onto carbon and low-alloy steel, where the high-alloy deposit tolerates dilution from the ferritic side. As-welded deposits give about 430 MPa yield, 600 MPa tensile and 36 % elongation, with the best corrosion rating of the 309 family here but a service limit near 400 °C. Where slightly higher carbon is acceptable and temperatures are higher, E309Mo is the nearest alternative. E309LMo 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). E309LMo has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 67% of stainless steel grades. Elongation at break is 36% and the elastic modulus is 197 GPa (28.6 Msi).
What is E309LMo used for?
- 316L to carbon steel transitions
- clad/overlay welding on pressure vessels
- chemical processing equipment
Advantages
- Readily welded — 90/100, better than 95% of stainless steel grades
Limitations
- Hard to polish — 55/100, worse than 89% of stainless steel grades
- Limited service temperature — 400°C (752 °F), worse than 78% of stainless steel grades
E309LMo properties
Typical room-temperature values for E309LMo-AW; bars are the position among stainless steel grades.
Physical3
E309LMo 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
E309LMo has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 67% of stainless steel grades. Elongation at break is 36% and the elastic modulus is 197 GPa (28.6 Msi).
Thermal6
E309LMo is rated for continuous service to 400°C (752 °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 15.5 µm/m·K (8.61 µin/in·°F).
Electrical3
E309LMo conducts electricity at 2.2 % IACS, worse than 61% 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 E309LMo takes about 55 MJ of energy and emits 5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 60%.
Manufacturability6
E309LMo's machinability is poor (32/100, worse than 62% of stainless steel grades); weldability excellent (90/100); formability fair (40/100).
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. E309LMo is highlighted; hover a dot for its name, or open the interactive family chart.
Working with E309LMo
Is E309LMo easy to machine?
Weld deposit machines like 316L — gummy and strongly work-hardening; use sharp carbide, positive rake, heavy feed and flood coolant, avoid dwelling.
Can E309LMo be welded?
SMAW with DCEP (AC also for -16/-17), short arc, stringer beads, interpass ≤150 °C; redry electrodes ~250–300 °C/1 h and keep ferrite 8–20 FN to avoid hot cracking.
Can E309LMo be formed, bent or molded?
Not a wrought product; deposited overlay can be lightly ground/peened but not cold formed as such.
E309LMo 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 | ≤ 0.04 | 0.03 |
| Cr | 22 – 25 | 23.5 |
| Ni | 12 – 14 | 13 |
| Mo | 2 – 3 | 2.5 |
| Mn | 0.5 – 2.5 | 1.3 |
| Sihigher end in -17 coating types | ≤ 0.9 | 0.6 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Cu | ≤ 0.75 | 0.1 |
| Fe | balance |
What surface finishes work on E309LMo?
Grind, pickle (HNO₃-HF paste) and passivate the deposit to restore the passive film; deposit is weakly magnetic so magnetic-particle testing is unreliable — use PT/UT.
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 E309LMo in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- W30923
- ASTM
- A5.4
How much does E309LMo cost?
E309LMo 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.
E309LMo — frequently asked
What is E309LMo used for?
E309LMo is typically used for 316L to carbon steel transitions, clad/overlay welding on pressure vessels and chemical processing equipment. In short: standard 316L-to-steel filler; most corrosion-resistant 309 type; low-carbon overlay electrode.
What is the yield strength of E309LMo?
E309LMo has a typical yield strength of 430 MPa (62.4 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 67% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is E309LMo easy to machine?
Not especially — machinability is rated poor (32/100, worse than 62% of stainless steel grades). Weld deposit machines like 316L — gummy and strongly work-hardening; use sharp carbide, positive rake, heavy feed and flood coolant, avoid dwelling.
Can E309LMo be welded?
Yes — weldability is rated excellent (90/100). SMAW with DCEP (AC also for -16/-17), short arc, stringer beads, interpass ≤150 °C; redry electrodes ~250–300 °C/1 h and keep ferrite 8–20 FN to avoid hot cracking.
What surface finishes work on E309LMo?
Grind, pickle (HNO₃-HF paste) and passivate the deposit to restore the passive film; deposit is weakly magnetic so magnetic-particle testing is unreliable — use PT/UT.
Can E309LMo be formed, bent or molded?
Not a wrought product; deposited overlay can be lightly ground/peened but not cold formed as such.
What is the maximum service temperature of E309LMo?
E309LMo is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between E309LMo-AW and E309LMo PWHT?
AW is the default condition — default condition for dissimilar joints and buttering layers; deposit used directly after welding with 8–20 FN ferrite. PWHT: applies when the C-steel/low-alloy component must be stress relieved; expect some ferrite transformation, slight strength gain and toughness loss. Yield strength is 430 MPa in AW versus 440 MPa in PWHT.
How much does E309LMo cost?
E309LMo 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 A5.4/A5.4M — Stainless Steel Electrodes for Shielded Metal Arc Welding — American Welding Society (2012)
- ASME BPVC Section II Part C, SFA-5.4 — ASME (2023)
- EN ISO 3581 — Covered electrodes for manual metal arc welding of stainless and heat-resisting steels — ISO/CEN (2016)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Stainless SMAW consumable datasheets (ESAB / Böhler / Lincoln 309LMo types) — various (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.