Stainless Steel E309
EN E309 · UNS W30910 · ASTM A5.4 · GB E309-16
E309 is a higher-alloy austenitic covered electrode (UNS W30910, AWS A5.4, classifications E309-15, -16, -17 and -26) used for joining stainless to carbon steel and for cladding.
Reference datasheet — E309 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 E309-16 condition
E309 tempers and conditions
E309 is supplied in 6 conditions, soft to hard. E309-16 is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Heavy iron-powder coated, high-recovery electrode | Use for high deposition-rate cladding and buffer layers on flat work; restricted to flat and horizontal-fillet positions. | 410 | 590 | 34 | 12 HRC | 2.2 % IACS |
Rutile/silica (acid-rutile) coated electrode, AC or DCEP | Choose for the flattest, smoothest bead appearance and best wetting in fillets and cladding; slightly higher Si, fluid slag, limited vertical-up performance. | 415 | 595 | 36 | 12 HRC | 2.2 % IACS |
E309-16Default Rutile (titania) coated covered electrode, AC or DCEP | Default stocked E309 electrode: smooth arc, easy slag release, AC or DCEP, all positions except vertical-down. | 420 | 600 | 37 | 11 HRC | 2.2 % IACS |
As-welded deposit | Reference condition for all mechanical data: undiluted deposit tested in the as-welded state, no PWHT. | 420 | 600 | 37 | 185 HB | 2.2 % IACS |
Lime (basic) coated covered electrode, DCEP only | Pick for maximum weld-metal toughness and cleanliness, out-of-position work and restrained dissimilar joints; DCEP only, rougher bead. | 430 | 610 | 40 | 10 HRC | 2.2 % IACS |
Post-weld heat treated | Condition when the joint must follow the carbon-steel side PWHT; expect ferrite transformation to sigma, higher strength/hardness and markedly lower toughness and ductility. | 440 | 620 | 28 | 200 HB | 2.3 % IACS |
What is E309?
E309 is a higher-alloy austenitic covered electrode (UNS W30910, AWS A5.4, classifications E309-15, -16, -17 and -26) used for joining stainless to carbon steel and for cladding. The extra chromium and nickel absorb dilution from carbon steel, so it is the standard buffer-layer filler before 308L or 316L overlay; as-welded deposit runs about 420 MPa yield, 600 MPa tensile, 37 % elongation and 185 HB (90 HRB), with service to 850 C. The deposit work-hardens quickly and is not intended for corrosion service matching 304. Use E309L where carbon must be kept low for wet corrosive duty. E309 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). E309 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 64% of stainless steel grades. Elongation at break is 37% and the elastic modulus is 196 GPa (28.4 Msi).
What is E309 used for?
- carbon-to-stainless dissimilar joints
- cladding on carbon steel
- buffer layers
Advantages
- Readily welded — 90/100, better than 95% of stainless steel grades
- High service temperature — 850°C (1,562 °F), better than 80% of stainless steel grades
Limitations
- Hard to polish — 55/100, worse than 89% of stainless steel grades
- High embodied carbon — 6 kg CO₂/kg, worse than 88% of stainless steel grades
E309 properties
Typical room-temperature values for E309-E309-16; bars are the position among stainless steel grades.
Physical3
E309 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).
Mechanical17
E309 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 64% of stainless steel grades. Elongation at break is 37% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal6
E309 is rated for continuous service to 850°C (1,562 °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 15 µm/m·K (8.33 µin/in·°F).
Electrical3
E309 conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (66/100), better than 59% of stainless steel grades.
Sustainability4
Producing a kilogram of E309 takes about 60 MJ of energy and emits 6 kg of CO₂ — more than 70% of stainless steel grades. Typical recycled content is 55%.
Manufacturability5
E309's machinability is fair (35/100, better than 51% of stainless steel grades); weldability excellent (90/100); formability fair (45/100).
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. E309 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with E309
Is E309 easy to machine?
Deposit machines like Type 309/310 — gummy and work-hardening; use sharp carbide, positive rake, heavy positive feed and no dwell, with flood coolant.
Can E309 be welded?
Redry electrodes (rutile ~120 °C, lime ~250–300 °C), keep a short arc, stringer beads, interpass below ~150 °C; one or two E309 buffer layers before depositing 308L/316L on carbon steel.
Can E309 be formed, bent or molded?
Not a wrought product — the deposit is ductile (≥30 % elongation) but rapidly work-hardens, so avoid cold straightening of clad or buffered assemblies.
E309 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 |
|---|---|---|
| Cundiluted weld metal, AWS A5.4 | ≤ 0.15 | 0.08 |
| Cr | 22 – 25 | 23.5 |
| Ni | 12 – 14 | 13 |
| Mn | 0.5 – 2.5 | 1.6 |
| Siupper end typical for -17 coatings | ≤ 0.9 | 0.6 |
| Moresidual only | ≤ 0.75 | 0.1 |
| Cu | ≤ 0.75 | 0.1 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Fe | balance |
What surface finishes work on E309?
Grind/blend with stainless-dedicated abrasives, then pickle and passivate; ferrite stringers can etch darker than the surrounding austenite when polished.
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 E309 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- W30910
- ASTM
- A5.4
- GB (China)
- E309-16
- Also called
- AWS A5.4 E309
How much does E309 cost?
E309 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.
E309 — frequently asked
What is E309 used for?
E309 is typically used for carbon-to-stainless dissimilar joints, cladding on carbon steel and buffer layers. In short: dissimilar-metal joining filler; standard buffer-layer electrode; service to 850 C.
What is the yield strength of E309?
E309 has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 64% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is E309 easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of stainless steel grades). Deposit machines like Type 309/310 — gummy and work-hardening; use sharp carbide, positive rake, heavy positive feed and no dwell, with flood coolant.
Can E309 be welded?
Yes — weldability is rated excellent (90/100). Redry electrodes (rutile ~120 °C, lime ~250–300 °C), keep a short arc, stringer beads, interpass below ~150 °C; one or two E309 buffer layers before depositing 308L/316L on carbon steel.
What surface finishes work on E309?
Grind/blend with stainless-dedicated abrasives, then pickle and passivate; ferrite stringers can etch darker than the surrounding austenite when polished.
Can E309 be formed, bent or molded?
Not a wrought product — the deposit is ductile (≥30 % elongation) but rapidly work-hardens, so avoid cold straightening of clad or buffered assemblies.
What is the maximum service temperature of E309?
E309 is rated for continuous use to about 850°C (1,562 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between E309-16 and E309 PWHT?
E309-16 is the default condition — default stocked E309 electrode: smooth arc, easy slag release, AC or DCEP, all positions except vertical-down. PWHT: condition when the joint must follow the carbon-steel side PWHT; expect ferrite transformation to sigma, higher strength/hardness and markedly lower toughness and ductility. Yield strength is 420 MPa in E309-16 versus 440 MPa in PWHT.
How much does E309 cost?
E309 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 — Specification for Stainless Steel Electrodes for Shielded Metal Arc Welding — American Welding Society (2012)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
- Stainless SMAW electrode E309/E309-16 all-weld-metal data — ESAB / Kobelco / (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.