Stainless Steel ER347Si PWHT-SA
Heat-treated state
UNS S34780 · EN 19 9 Nb Si
PWHT-SA = post-weld stabilizing anneal
Use when the joint will see long-term 400–800 °C service or aggressive acid media and maximum resistance to intergranular attack is required.
Values for the PWHT-SA condition
Other ER347Si tempers and conditions
ER347Si is listed in 5 conditions; see the grade overview at ER347Si.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
PWHT-SAThis page Post-weld stabilizing anneal | Use when the joint will see long-term 400–800 °C service or aggressive acid media and maximum resistance to intergranular attack is required. | 350 | 570 | 42 | 170 HB | 2.4 % IACS |
As-welded, submerged-arc deposit with neutral/basic flux | For thick-section and cladding work at high deposition rate; properties depend strongly on flux, keep Nb/Si recovery and ferrite in check. | 385 | 585 | 34 | 180 HB | 2.4 % IACS |
As-welded, TIG deposit with Ar shielding | Choose for thin sections, root passes and cleanest deposits; highest ductility and toughness of the process options. | 395 | 595 | 40 | 185 HB | 2.4 % IACS |
AWDefault As-welded deposit | Default reported condition: undiluted all-weld-metal properties as deposited, no post-weld heat treatment. | 410 | 610 | 37 | 12 HRC | 2.4 % IACS |
As-welded, MIG/MAG spray or pulsed deposit | Main reason to pick 347Si over 347: high Si gives flat, well-wetted MIG beads and stable spray/pulse transfer at high deposition rates. | 420 | 620 | 35 | 195 HB | 2.4 % IACS |
What is ER347Si PWHT-SA?
ER347Si PWHT-SA is ER347Si heat treated to PWHT-SA — use when the joint will see long-term 400–800 °C service or aggressive acid media and maximum resistance to intergranular attack is required. ER347Si PWHT-SA has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 52% of stainless steel grades. Elongation at break is 42% and the elastic modulus is 195 GPa (28.3 Msi). ER347Si PWHT-SA has a density of 7.95 g/cm³ (0.287 lb/in³), heavier than 81% of stainless steel grades. It melts at 1,400°C (2,552 °F). AW is the default condition FabDigit quotes; PWHT-SA is available on request or by drawing note.
Advantages
- Readily welded — 95/100, better than 99% of stainless steel grades
- High service temperature — 850°C (1,562 °F), better than 80% of stainless steel grades
- Tough — resists crack growth — 185 MPa·√m (168.4 ksi·√in), better than 77% of stainless steel grades
Limitations
- High embodied carbon — 6.5 kg CO₂/kg, worse than 93% of stainless steel grades
ER347Si PWHT-SA properties
Typical room-temperature values for ER347Si PWHT-SA; 22 are specific to this condition. Other listed values are ER347Si reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
ER347Si PWHT-SA has a density of 7.95 g/cm³ (0.287 lb/in³), heavier than 81% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical17
ER347Si PWHT-SA has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 52% of stainless steel grades. Elongation at break is 42% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
ER347Si PWHT-SA is rated for continuous service to 850°C (1,562 °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 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
ER347Si PWHT-SA conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (66/100), better than 59% of stainless steel grades.
Sustainability4
Producing a kilogram of ER347Si PWHT-SA takes about 55 MJ of energy and emits 6.5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 70%.
Manufacturability7
ER347Si PWHT-SA's machinability is fair (42/100, better than 79% of stainless steel grades); weldability excellent (95/100); formability good (66/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ER347Si PWHT-SA
Is ER347Si easy to machine?
Weld metal machines like Type 347: gummy, work-hardening, needs sharp carbide tooling, rigid setup, positive rake, heavy coolant and low surface speed (~40% of 1212).
Can ER347Si be welded?
Use for 321/347/304H and stabilized-to-stabilized joints; keep interpass below ~150 °C, ferrite 4–10 FN, Ar or Ar+2% O₂/CO₂ (max ~2.5% CO₂) to protect Nb, avoid high heat input to limit hot-crack sensitivity from the higher Si.
Can ER347Si be formed, bent or molded?
Supplied as cold-drawn wire; deposit is fully ductile austenite and tolerates cold straightening/bending of the joint, but expect strong work hardening and springback.
What surface finishes work on ER347Si?
Pickle and passivate or electropolish weld area to restore the chromium oxide film; light ferrite in the bead can etch slightly darker and shows faint magnetism — no anodizing.
ER347Si 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 A5.9 max | ≤ 0.08 | 0.05 |
| Cr | 19 – 21.5 | 20 |
| Ni | 9 – 11 | 9.8 |
| NbNb+Ta; minimum = 10 × C per AWS A5.9 | ≤ 1 | 0.7 |
| Mn | 1 – 2.5 | 1.7 |
| Sihigh-Si variant — improves wetting | 0.65 – 1 | 0.85 |
| Moresidual | ≤ 0.75 | 0.15 |
| Curesidual | ≤ 0.75 | 0.15 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Fe | balance | — |
ER347Si PWHT-SA — frequently asked
What is ER347Si PWHT-SA used for?
ER347Si PWHT-SA is typically used for automated MIG welding of stabilized stainless, type 321 and 347 pipe and pressure vessel joints, 304H high-temperature piping and headers, stabilized-to-stabilized stainless structural welds, furnace and flue ductwork fabrication and heat exchanger shell and nozzle welds. In short: best-wetting stabilized austenitic filler; nb-stabilized for 321/347; deposit rated to 800 °C.
What is the yield strength of ER347Si PWHT-SA?
ER347Si PWHT-SA has a typical yield strength of 350 MPa (50.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 52% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is ER347Si PWHT-SA easy to machine?
Not especially — machinability is rated fair (42/100, better than 79% of stainless steel grades). Weld metal machines like Type 347: gummy, work-hardening, needs sharp carbide tooling, rigid setup, positive rake, heavy coolant and low surface speed (~40% of 1212).
Can ER347Si PWHT-SA be welded?
Yes — weldability is rated excellent (95/100). Use for 321/347/304H and stabilized-to-stabilized joints; keep interpass below ~150 °C, ferrite 4–10 FN, Ar or Ar+2% O₂/CO₂ (max ~2.5% CO₂) to protect Nb, avoid high heat input to limit hot-crack sensitivity from the higher Si.
What surface finishes work on ER347Si PWHT-SA?
Pickle and passivate or electropolish weld area to restore the chromium oxide film; light ferrite in the bead can etch slightly darker and shows faint magnetism — no anodizing.
Can ER347Si PWHT-SA be formed, bent or molded?
Supplied as cold-drawn wire; deposit is fully ductile austenite and tolerates cold straightening/bending of the joint, but expect strong work hardening and springback.
What is the maximum service temperature of ER347Si PWHT-SA?
ER347Si PWHT-SA 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 ER347Si-AW and ER347Si PWHT-SA?
AW is the default condition — default reported condition: undiluted all-weld-metal properties as deposited, no post-weld heat treatment. PWHT-SA: use when the joint will see long-term 400–800 °C service or aggressive acid media and maximum resistance to intergranular attack is required. Yield strength is 410 MPa in AW versus 350 MPa in PWHT-SA.
Sources
- AWS A5.9/A5.9M — Bare Stainless Steel Welding Electrodes and Rods — American Welding Society (2017)
- ASME BPVC Section II Part C, SFA-5.9 — ASME (2023)
- ISO 14343 (19 9 Nb Si) — Welding consumables, wire electrodes for stainless steels — ISO (2017)
- ASM Handbook Vol.1 — Properties of Wrought Stainless Steels (Type 347) — ASM International (1990)
- ASM Handbook Vol.6 — Welding of Stainless Steels — ASM International (1993)
- 347Si / 19 9 Nb Si solid wire datasheets (all-weld-metal typicals) — Böhler Welding / Sandvik / 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.