Stainless Steel E318 PWHT
Heat-treated state
EN E318 · UNS W31910
PWHT = post-weld heat treated
Used when the fabrication is stabilizing-annealed with the base metal; softens the deposit and lowers ferrite slightly.
Values for the PWHT condition
Other E318 tempers and conditions
E318 is listed in 5 conditions; see the grade overview at E318.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
PWHTThis page Post-weld heat treated | Used when the fabrication is stabilizing-annealed with the base metal; softens the deposit and lowers ferrite slightly. | 360 | 560 | 40 | 165 HB | 2.3 % IACS |
Silica-titania coating, AC or DCEP, higher deposition | Choose for flat/horizontal fillets where bead appearance and deposition rate matter; slightly more fluid slag than -16. | 410 | 580 | 36 | 178 HB | 2.2 % IACS |
AWDefault As-welded deposit | Standard supply/qualification condition: properties of the deposit as deposited, tested per AWS A5.4. | 415 | 590 | 35 | 180 HB | 2.2 % IACS |
Titania (rutile) coating, AC or DCEP, all positions | Most widely stocked type: smooth arc, easy slag release, AC-capable — general fabrication of 316Cb/316Ti. | 415 | 590 | 35 | 180 HB | 2.2 % IACS |
Lime (basic) coating, DCEP, all positions | Pick for root passes, restrained joints and best low-temperature/impact toughness; DC only, slightly rougher bead. | 420 | 585 | 36 | 180 HB | 2.2 % IACS |
What is E318 PWHT?
E318 PWHT is E318 heat treated to PWHT — used when the fabrication is stabilizing-annealed with the base metal; softens the deposit and lowers ferrite slightly. E318 PWHT 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 40% and the elastic modulus is 193 GPa (28 Msi). E318 PWHT has a density of 7.96 g/cm³ (0.288 lb/in³), heavier than 83% of stainless steel grades. It melts at 1,375°C (2,507 °F). AW is the default condition FabDigit quotes; PWHT is available on request or by drawing note.
Advantages
- Readily welded — 88/100, better than 91% of stainless steel grades
- Good corrosion resistance — 75/100, better than 79% of stainless steel grades
E318 PWHT properties
Typical room-temperature values for E318 PWHT; 23 are specific to this condition. Other listed values are E318 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
E318 PWHT has a density of 7.96 g/cm³ (0.288 lb/in³), heavier than 83% of stainless steel grades. It melts at 1,375°C (2,507 °F).
Mechanical16
E318 PWHT 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 40% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
E318 PWHT is rated for continuous service to 800°C (1,472 °F). It conducts heat at 16.3 W/m·K (9.42 BTU/hr·ft·°F), better than 68% of stainless steel grades. Thermal expansion is 16 µm/m·K (8.89 µin/in·°F).
Electrical3
E318 PWHT conducts electricity at 2.3 % IACS, better than 55% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (75/100), better than 79% of stainless steel grades.
Sustainability4
Producing a kilogram of E318 PWHT takes about 55 MJ of energy and emits 5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
E318 PWHT's machinability is poor (34/100, worse than 55% of stainless steel grades); weldability excellent (88/100); formability good (58/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with E318 PWHT
Is E318 easy to machine?
Deposit machines like 316: low speed, heavy positive-rake carbide, rigid setup and flood coolant to avoid work hardening; grind slag inclusions out first.
Can E318 be welded?
SMAW with short arc, stringer beads, interpass ≤150 °C and no preheat; redry electrodes 250–300 °C/1 h and keep hot to avoid porosity and moisture pickup.
Can E318 be formed, bent or molded?
Not a wrought product — deposit is ductile (≈35 % elongation) and tolerates weld-joint straightening, but heavy cold work raises hardness quickly.
What surface finishes work on E318?
Remove all slag, then pickle/passivate (HNO₃-HF or citric per ASTM A967) or blast with stainless-only media to restore the passive film; electropolishing gives best chloride performance.
E318 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 |
|---|---|---|
| CAWS A5.4 undiluted weld metal | ≤ 0.08 | 0.05 |
| Cr | 17 – 20 | 18.5 |
| Ni | 11 – 14 | 12 |
| Mo | 2 – 3 | 2.5 |
| NbNb+Ta, min = 6×C | 0.48 – 1 | 0.7 |
| Mn | 0.5 – 2.5 | 1.4 |
| Si | ≤ 0.9 | 0.6 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Cu | ≤ 0.75 | 0.1 |
| Fe | balance | — |
E318 PWHT — frequently asked
What is E318 PWHT used for?
E318 PWHT is typically used for high-temperature stabilized piping, petrochemical equipment and stabilized stainless fabrication. In short: stabilized 316-type deposit; service to 800 °C; nb-stabilized alternative to E316L.
What is the yield strength of E318 PWHT?
E318 PWHT 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 5 listed tempers.
Is E318 PWHT easy to machine?
Not especially — machinability is rated poor (34/100, worse than 55% of stainless steel grades). Deposit machines like 316: low speed, heavy positive-rake carbide, rigid setup and flood coolant to avoid work hardening; grind slag inclusions out first.
Can E318 PWHT be welded?
Yes — weldability is rated excellent (88/100). SMAW with short arc, stringer beads, interpass ≤150 °C and no preheat; redry electrodes 250–300 °C/1 h and keep hot to avoid porosity and moisture pickup.
What surface finishes work on E318 PWHT?
Remove all slag, then pickle/passivate (HNO₃-HF or citric per ASTM A967) or blast with stainless-only media to restore the passive film; electropolishing gives best chloride performance.
Can E318 PWHT be formed, bent or molded?
Not a wrought product — deposit is ductile (≈35 % elongation) and tolerates weld-joint straightening, but heavy cold work raises hardness quickly.
What is the maximum service temperature of E318 PWHT?
E318 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 E318-AW and E318 PWHT?
AW is the default condition — standard supply/qualification condition: properties of the deposit as deposited, tested per AWS A5.4. PWHT: used when the fabrication is stabilizing-annealed with the base metal; softens the deposit and lowers ferrite slightly. Yield strength is 415 MPa in AW versus 360 MPa in PWHT.
Sources
- AWS A5.4/A5.4M — Stainless Steel Electrodes for Shielded Metal Arc Welding — American Welding Society (2012)
- GB/T 983 — (stainless steel covered electrodes) — SAC (2012)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
- 316Cb / E318 covered electrode all-weld-metal data — Böhler Welding / ESAB (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.