Stainless Steel E309 PWHT
Heat-treated state
EN E309 · UNS W30910 · ASTM A5.4 · GB E309-16
PWHT = 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.
Values for the PWHT condition
Other E309 tempers and conditions
E309 is listed in 6 conditions; see the grade overview at E309.
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 |
PWHTThis page 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 PWHT?
E309 PWHT is E309 heat treated to 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. E309 PWHT has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 68% of stainless steel grades. Elongation at break is 28% and the elastic modulus is 196 GPa (28.4 Msi). E309 PWHT 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). E309-16 is the default condition FabDigit quotes; PWHT is available on request or by drawing note.
Advantages
- Readily welded — 85/100, better than 87% 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 PWHT properties
Typical room-temperature values for E309 PWHT; 22 are specific to this condition. Other listed values are E309 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
E309 PWHT 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 PWHT has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 68% of stainless steel grades. Elongation at break is 28% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal6
E309 PWHT is rated for continuous service to 800°C (1,472 °F). It conducts heat at 15.8 W/m·K (9.13 BTU/hr·ft·°F), better than 55% of stainless steel grades. Thermal expansion is 15 µm/m·K (8.33 µin/in·°F).
Electrical3
E309 PWHT conducts electricity at 2.3 % IACS, better than 55% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 71% of stainless steel grades.
Sustainability4
Producing a kilogram of E309 PWHT 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 PWHT's machinability is poor (33/100, worse than 57% of stainless steel grades); weldability excellent (85/100); formability fair (36/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with E309 PWHT
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.
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.
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 | — |
E309 PWHT — frequently asked
What is E309 PWHT used for?
E309 PWHT 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 PWHT?
E309 PWHT has a typical yield strength of 440 MPa (63.8 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 68% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is E309 PWHT easy to machine?
Not especially — machinability is rated poor (33/100, worse than 57% 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 PWHT be welded?
Yes — weldability is rated excellent (85/100). 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 PWHT?
Grind/blend with stainless-dedicated abrasives, then pickle and passivate; ferrite stringers can etch darker than the surrounding austenite when polished.
Can E309 PWHT 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 PWHT?
E309 PWHT is rated for continuous use to about 800°C (1,472 °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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.