AWS Class E347T1-1/T1-4 Flux Core
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E347T1-1/T1-4 Niobium-Stabilised Stainless Steel Flux Cored Wire Supplier
Nicorex Alloys is an ISO 9001 and ISO 14001 certified supplier of E347T1-1/T1-4 niobium-stabilised stainless steel flux cored wire, based in Mumbai, India. We provide these wires classified under AWS A5.22 (ASME SFA 5.22).
E347T1-1/T1-4 weld deposit contains approximately 19.5% Cr, 9.5% Ni, and 0.40% Nb with carbon held at ≤0.08%. Niobium forms stable NbC carbides preferentially over Cr₂₃C₆, locking carbon before it can deplete grain boundary chromium. We also operate as an importer of this columbium-stabilised FCAW wire. When austenitic stainless steel operates between 400°C and 900°C, the sensitisation range, only a niobium-stabilised weld deposit protects grain boundaries from chromium carbide precipitation and the intergranular corrosion that follows. AWS A5.22 E347T1-1/T1-4 flux cored wire delivers that protection. This gas-shielded rutile-type FCAW electrode carries UNS W34731 (T1-1, 100% CO₂) and W34735 (T1-4, 75-80% Ar / 20-25% CO₂). It’s purpose-built for joining Nb-stabilised 18Cr-8Ni austenitic stainless steels: Types 347, 321, and unstabilised 304/308 in elevated-temperature service. Typical tensile strength reaches 85,000 psi (586 MPa) with 35% elongation. Available diameters are 0.9 mm, 1.2 mm, and 1.6 mm, all rated for all-position welding on DCEP.
Primary base metals include AISI 347, 347H, 321, 321H, 304, 304H, 302, and castings CF-8 and CF-8C. Industries span power generation, petrochemical, refinery, nuclear, aerospace, and chemical processing: sectors where welds face prolonged thermal exposure in the sensitisation range. As importer and stockist, Nicorex Alloys supplies every spool with EN 10204/3.1B mill test certificates, PMI reports, and full batch traceability documentation.
E347T1-1/T1-4 Flux Cored Wire Specifications
The specification table below covers standards, designations, and process details for this Nb-stabilised 347 stainless welding wire:
| ASME SFA Specification | SFA-5.22 (ASME Section II Part C) |
|---|---|
| UNS Number | W31735 |
| Welding Process | FCAW-G (Gas-Shielded Flux-Cored Arc Welding) |
| Flux System | Rutile-type (TiO₂-based); fast-freezing slag |
| Polarity | DCEP |
| Welding Positions | All: Flat, Horizontal, Vertical-Up, Overhead |
| Shielding Gas |
T1-1 : 100% CO₂ at 12–20 L/min (25–40 cfh) T1-4 : 75–80% Ar/bal. CO₂ at 12–20 L/min |
| Diameters | 0.9 mm (0.035″), 1.2 mm (0.045″), 1.6 mm (1/16 ″) |
| Spool Types & Weights | D200: 5 kg; D300/BS300: 12.5 kg, 15 kg — vacuum-sealed |
| CTWD | 12–20 mm; optimum 15–19 mm |
| Transfer Mode | Rutile FCAW wires project globular metal transfer. |
| Deposition Rate | ~1.5–3.2 kg/hr |
| Deposition Efficiency | ~85–90% |
| Max Interpass Temp. | 150°C (302°F) |
| Preheat | Not required for P-8 base metals |
| PWHT | Not recommended (sensitisation/sigma risk) |
| Shelf Life (sealed) | 24 months from the manufacture date |
AWS A5.22 Classification of E347T1-1/T1-4 Flux Cored Wire
The classification of E347T1-1/T1-4 cored wire, along with its designation and meaning, is listed below:
| Designaton | Meaning |
|---|---|
| E | Electrode: flux-cored wire that carries welding current to the arc. |
| 347 | Nb-stabilised 347 weld metal uses niobium to form NbC, avoiding chromium carbide at grain boundaries, unlike 308L and 316L. |
| T | Tubular electrode (flux cored wire) : the flux in the core controls slag system, arc characteristics, and ferrite balance. |
| 1 | Suitable for all positions, flat, horizontal, vertical-up, and overhead. In FCAW, “1” means all positions; “0” restricts to flat/horizontal fillets. |
| -1 | Uses pure CO₂ shielding; E347T1-1 wire, tuned for 35-50 cfh, delivers stable arc and penetration for fabrication. |
| -4 | Mixed-gas option: 75-80% Ar / 20-25% CO₂; E347T1-4 improves transfer, lowers spatter, and enhances bead wetting. |
E347T1 is a flux‑cored wire used to weld stabilised austenitic stainless steels such as 347, 321, and high‑temperature 304/304H. It is niobium‑stabilised, so Nb forms fine NbC particles that stop chromium carbide from precipitating at grain boundaries, preserving chromium and resistance to sensitisation between 400-900°C. The grade permits carbon up to 0.08% while maintaining corrosion resistance, and E347T1‑1 / T1‑4 provide creep strength and all‑position capability with defined shielding gases.
Chemical Composition of E347T1 Weld Deposit (%)
The chemical composition of the E347T1 Weld Deposit and its proportion in percentage is mentioned in the table below:
| Element | Carbon (C) | Manganese (Mn) | Silicon (Si) | Chromium (Cr) | Nickel (Ni) | Niobium (Nb) | Molybdenum (Mo) | Phosphorus (P) | Sulfur (S) | Copper (Cu) | Iron (Fe) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| AWS A5.22 Requirement | 0.08 max | 0.50-2.50 | 1.00 max | 18.0-21.0 | 9.0-11.0 | 8×C min – 1.0 max | 0.75 max | 0.04 max | 0.03 max | 0.75 max | Balance |
| Typical | 0.05 | 1.20 | 0.60 | 19.50 | 9.50 | 0.40 | 0.28 | 0.02 | 0.01 | 3 | Balance |
The higher carbon allowance (0.08% vs 0.04% for E308LT1) contributes to improved creep resistance at elevated temperatures. Nb also provides grain refinement and precipitation strengthening through fine NbC dispersion. Although AWS uses “Cb” (columbium) in older designations, the element is internationally designated niobium (Nb) per IUPAC; both terms refer to atomic number 41.
Mechanical Properties of E347T1 Weld Deposit
Mechanical properties of E347T1 Weld Deposit, including tensile strength, yield strength, elongation and ferrite number is mentioned in the table below:
| Property | Tensile Strength | Yield Strength (0.2%) | Elongation (%) | Ferrite Number |
|---|---|---|---|---|
| AWS A5.22 Requirement | ≥75,000 psi (520 MPa) | Not specified | ≥30% | Not specified |
| Typical | 82,300-85,000 psi (567-586 MPa) | 58,000-58,700 psi (400-405 MPa) | 35-38% | 5-10 FN |
E347T1 deposits have lower ferrite (5-10 FN) than E308LT1 (8-12 FN) because niobium promotes austenite. If the dilution drops ferrite below 3 FN, hot cracking susceptibility increases. For service above 540°C (1000°F) under creep conditions, E347HT1 (C ≥0.04%) is recommended for improved rupture strength. Standard E347T1 suits service below 540°C under stress, and up to ~870°C (1600°F) in non-pressure applications such as furnace parts.
Base Metal Compatibility & P-Number Matrix for E347T1
E347T1 is the mandatory filler for Types 347, 347H, 321, and 321H when service temperature exceeds 260°C (500°F). Below 260°C, E308LT1 for ambient-temperature 304/304L service may be used. Above 260°C, unstabilised deposits risk sensitisation and knife-line attack in the HAZ of stabilised base metals.
| Base Metal | UNS | P-Number | Service Temperature |
|---|---|---|---|
| Type 347 (Nb-stabilised) | S34700 | P-8 Group 1 | Up to 870°C (non-stress) / 540°C (stress) |
| Type 347H | S34709 | P-8 Group 1 | Elevated-temp creep service |
| Type 321 (Ti-stabilised) | S32100 | P-8 Group 1 | Up to 870°C (non-stress) |
| Type 321H | S32109 | P-8 Group 1 | Elevated-temp creep service |
| Type 304 | S30400 | P-8 Group 1 | When service >260°C requires stabilisation |
| Type 304H | S30409 | P-8 Group 1 | Elevated-temp service |
| Type 302 | S30200 | P-8 Group 1 | When service >260°C |
| CF-8 (Cast) | J92600 | P-8 Group 1 | When service >260°C |
| CF-8C (Cast 347) | J92710 | P-8 Group 1 | Nb-stabilised castings |
ASME Section IX classifies E347T1 as F-6 / A-8. For Types 304 and 304H above 400°C, Nb stabilisation in E347T1 protects against sensitisation more reliably than carbon control alone, making it the conservative choice for critical high-temperature pressure equipment.
Recommended Welding Parameters for E347T1-1/T1-4
Heat input control in stabilised-grade welding serves a dual purpose: managing weld deposit microstructure and controlling the sensitisation zone in the base metal HAZ. Excessive heat input can dissolve NbC precipitates in 347/321 HAZ, freeing carbon to form Cr₂₃C₆ upon cooling.
| Diameter | Position | Optimum Amps | Optimum Volts | Range Amps | Range Volts |
|---|---|---|---|---|---|
| 0.9 mm (0.035″) | Flat/Horizontal | 130-140 | 24-25 | 100-170 | 21-26 |
| 0.9 mm (0.035″) | Vertical-Up | 110-120 | 22-23 | 110-120 | 21-23 |
| 0.9 mm (0.035″) | Overhead | 120-130 | 23-24 | 120-130 | 22-24 |
| 1.2 mm (0.045″) | Flat/Horizontal | 180-200 | 25-27 | 135-250 | 24-32 |
| 1.2 mm (0.045″) | Vertical-Up | 150-170 | 24-26 | 135-200 | 24-26 |
| 1.2 mm (0.045″) | Overhead | 175-195 | 25-27 | 155-200 | 25-28 |
| 1.6 mm (1/16″) | Flat/Horizontal | 220-240 | 25-27 | 170-300 | 24-31 |
| 1.6 mm (1/16″) | Vertical-Up | 190-210 | 25-26 | 170-230 | 24-27 |
| 1.6 mm (1/16″) | Overhead | 200-220 | 25-26 | 170-270 | 24-29 |
Preheat isn’t required; maintain ambient minimum 10°C. Interpass: max 175°C (350°F). Stringer beads are preferred over weaving. PWHT is generally not required. Do not stress-relieve in the 425-870°C sensitisation range without stabilisation protection.
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Elevated-Temperature Industrial Applications of E347T1-1/T1-4
E347T1-1/T1-4 is specified in industrial applications like petrochemical and refineries, aerospace, furnace, and kiln components:
- Petrochemical & Refinery: Catalytic reformer tubes, hydrogen reformer pigtails, ethylene cracker outlet piping, and FCC reactor internals operate at 400-700°C with cyclic thermal exposure.
- Power Generation: Boiler superheater and reheater tubes at 500-600°C use 347H tubing welded with E347T1 for long-term creep resistance.
- Nuclear: Nuclear-grade 347/321 piping for primary coolant and auxiliary service requires ASME Section III compliance.
- Chemical Processing: Reactors and pressure vessels operating in the sensitisation range while exposed to corrosive media depend on Nb-stabilised deposits.
- Aerospace & Gas Turbine Exhaust Systems: Exhaust manifolds, afterburner liners, and APU exhaust ducting fabricated from 321/347 sheet reach 600-870°C intermittently.
- Furnace & Kiln Components: Furnace parts, kiln liners, radiant tubes, muffles, and thermowell housings operate at 700-900°C.
Storage & Handling of E347T1 Flux Cored Wire
E347T1-1/T1-4 follows the same storage protocols as all gas-shielded stainless FCAW wires: sealed storage at 15-25°C with RH below 60%, immediate consumption after opening, and transfer to a heated cabinet (40-50°C) if not used within the shift. Flux-cored wire can’t be rebaked: prevention of moisture ingress is the only effective approach.
How to Order E347T1-1/T1-4 from Nicorex Alloys
To order E347T1-1/T1-4 from Nicorex Alloys, follow these 11 important details:
- Wire Type - FCAW-G Tubular Wire (E347T1-1 / T1-4)
- Size - Diameter: 0.9 mm / 1.2 mm / 1.6 mm, specify spool size (5 kg / 15 kg)
- Shielding Gas - T1-1: 100% CO₂ / T1-4: 75–80% Ar + 20–25% CO₂, specify suffix
- Current Type - DCEP, specify wire feed speed and voltage per diameter
- Welding Position - All Positions (1G–6G), specify if positional welding is required
- Material Grade - Niobium-Stabilised Austenitic FCAW Wire / UNS S34700 / AWS A5.22: E347T1-1/T1-4
- Quantity - Number of spools or total weight in kg
- Standard - AWS A5.22 / ASME SFA 5.22, EN ISO 17633-A: T 19 9 Nb, ASME Section IX
- Documentation - MTC EN 10204 3.1/3.2, PMI Report, Weld Metal Composition Report, Mechanical Properties Report, IGC Test Report, TPI Certificate
- Packaging - Vacuum-sealed moisture-proof foil spool bag with silica gel desiccant, ISPM 15 compliant export cartons with full labelling
- Delivery Destination - Domestic
Frequently Asked Questions
Why is E347T1 required instead of E308LT1 for Welding 321 and 347 stainless steel above 260°C?
Above 260°C, E347T1 is required because its niobium forms NbC precipitates that prevent chromium carbide sensitisation and intergranular corrosion, unlike low‑carbon E308LT1.
Can E347T1 Weld Type 304 Stainless Steel for Elevated-Temperature Service?
Yes, E347T1 can weld Type 304 above 260°C to improve sensitisation resistance in the weld, though the 304 HAZ can still be vulnerable.
Does E347T1 carry the same F-Number as E308LT1 for ASME WPS Qualification?
Yes, both are F‑6 / A‑8, so E347T1 can replace E308LT1 on a WPS without requalification for elevated‑temperature service.
Is E347T1 suitable for Cryogenic Service Below -196°C?
Generally, no, because its 5-10 FN ferrite can reduce impact toughness, so cryogenic‑rated E308LT1 is preferred.
How does E347T1 compare to E308HT1 for Elevated-Temperature Stainless Steel Service?
E347T1 is superior when both sensitisation resistance and creep strength are needed, while E308HT1 suits mainly high‑creep but mild‑corrosion environments.