AWS Class E2594T1-1/T1-4 Flux Core
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E2594T1-1/T1-4 Super Duplex Stainless Steel Flux Cored Wire: Supplier in India
Nicorex Alloys is an ISO 9001 and ISO 14001 certified stockist, dealer, and supplier of E2594T1-1/T1-4 Super Duplex Stainless Steel Flux Cored Wire in Mumbai, India. We provide these DSS flux-cored wires as classified under AWS A5.22 / ASME SFA-5.22.
The wire carries two gas designators: E2594T1-1 (CO₂ shielded) and E2594T1-4 (75%Ar/25%CO₂ shielded), commercially known as Super Duplex 2594 FCAW Wire or 2507-type Flux Cored Electrode. This rutile-type tubular electrode deposits approximately 25.5% Cr, 9.5% Ni, 3.5% Mo, and 0.25% N, producing PREN of 41–42. This is the metallurgical threshold that defines a super duplex weld deposit, and E2594T1-1/T1-4 is the FCAW consumable built to cross it. Minimum tensile strength is 760 MPa (110 ksi), typical 860–880 MPa; elongation 15% minimum, typical 20–26%; ferrite 40–60 FN. Available in 1.2 mm and 1.6 mm on standard spools (5 kg, 12.5 kg, 15 kg, 25 lb, 33 lb), the wire welds all positions at 1.2 mm, with flat and horizontal recommended for 1.6 mm.
Primary base metals include UNS S32750 (2507), S32760 (Zeron 100), S32550 (Ferralium 255), cast grades J93380/J93404, plus dissimilar joints to duplex 2205 and carbon steel. They comply with AWS A5.22, ASME SFA-5.22, and EN ISO 17633, with ABS, DNV, Lloyds, BV, and CWB approvals available. Offshore oil and gas, desalination, and chemical processing are the primary sectors. Every spool ships batch-tested with MTC 3.1 per EN 10204.
E2594T1-1/T1-4 Super Duplex Flux Cored Wire Specifications
The table below consolidates all parameters for E2594T1-1/T1-4 per AWS A5.22. Welding engineers can reference these values when qualifying procedures.
| UNS Number | W39594 |
|---|---|
| Welding Process | FCAW-G (Gas Shielded) |
| Flux Core Type | Rutile (titania-based, fast-freezing slag) |
| Polarity | DCEP |
| Welding Positions | All positions (1.2 mm); Flat & Horizontal recommended (1.6 mm) |
| Shielding Gas | 75%Ar/25%CO₂ (recommended) or 100% CO₂ |
| Gas Flow Rate | 15–25 L/min (35–50 CFH) |
| Available Diameters | 1.2 mm (0.045”/0.047”), 1.6 mm (1/16”) |
| Spool Sizes | 5 kg, 12.5 kg (D300), 15 kg (33 lb), 25 lb, 28 lb |
| Deposition Efficiency | ~86–89% |
AWS Classification E2594T1-1/T1-4
The E2594T1-1/T1-4 classification follows AWS A5.22 for stainless steel flux-cored electrodes. Each character carries a specific meaning for welding engineers:
| Designator | Meaning |
|---|---|
| E | Electrode: a consumable electrode carrying welding current |
| 2594 | Weld deposit composition: super duplex weld metal with nominally 25% Cr, 9% Ni, 4% Mo. The “25-9-4” pattern distinguishes it from “2209” (standard duplex: 22-9-3). Also implies ~0.25% N and Cu allowance up to 1.5%. |
| T | Tubular: flux cored (tubular) electrode construction |
| 1 (position) | All-position welding capability. 1.6 mm diameter may be practically limited to flat/horizontal. |
| -1 (gas) | Classified with 100% CO₂ shielding OR Ar/CO₂ mixed gas |
| -4 (gas) | Classified with 75–80% Ar / 20–25% CO₂ mixed gas |
Products meeting both gas designators carry the dual classification E2594T1-1/T1-4 (UNS W39594). The critical difference from E2209T1 is that E2594T1 deposits PREN >40 (super duplex) vs approximately PREN 35 for E2209T1. That gap dictates which base metals and corrosion environments the weld can serve.
E2594T1-1/T1-4 Weld Deposit Chemical Composition
Values below represent all-weld-metal chemical analysis, not wire or base metal composition. Weld deposit chemistry differs due to flux contribution and dilution.
| Material / Element | Carbon (C) | Manganese (Mn) | Silicon (Si) | Chromium (Cr) | Nickel (Ni) | Molybdenum (Mo) | Nitrogen (N) | Phosphorus (P) | Sulphur (S) | Copper (Cu) | Tungsten (W) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| AWS A5.22 Requirement (wt%) | ≤0.04 | 0.50–2.50 | ≤1.00 | 24.0–27.0 | 8.0–10.5 | 2.5–4.5 | 0.20–0.30 | ≤0.04 | ≤0.03 | ≤1.50 | ≤1.00 |
| Typical Values (wt%) | 0.02–0.03 | 0.75–1.10 | 0.42–0.57 | 25.0–26.8 | 9.0–9.5 | 3.5–4.1 | 0.23–0.25 | ≤0.020 | ≤0.006 | ≤0.20 | ≤0.06 |
PREN Calculation: PREN = %Cr + 3.3 × (%Mo + 0.5 × %W) + 16 × %N. Using typical values: 25.5 + 3.3 × (3.56 + 0.03) + 16 × 0.25 = 41.4, exceeding the >40 super duplex threshold.
Overmatched Ni (~9–10% vs ~7% in 2507 base metal) promotes austenite formation to achieve 40–60 FN ferrite as-welded. The W allowance up to 1.0% reflects Zeron 100-type compositions.
E2594T1-1/T1-4 All-Weld-Metal Mechanical Properties
These are all-weld-metal properties per AWS A5.22 in the as-welded condition. Ar/CO₂ shielding typically gives slightly higher elongation and impact values than 100% CO₂.
| Property | Tensile Strength | Yield Strength | Elongation (50 mm) | CVN Impact (−20°C) | CVN Impact (−50°C) | Hardness | Ferrite Number (WRC-92) |
|---|---|---|---|---|---|---|---|
| AWS A5.22 Minimum | ≥760 MPa (110 ksi) | Not specified | ≥15% | Not specified | Not specified | Not specified | Not specified |
| Typical (75%Ar/25%CO₂) | 860–890 MPa (125–129 ksi) | 660–715 MPa (96–104 ksi) | 24–26% | 27–37 J | 20–30 J | 270–330 HV10 typical | 55–60 FN |
| Typical (100% CO₂) | 830–880 MPa (120–128 ksi) | 630–690 MPa (91–100 ksi) | 20–24% | 20–30 J | Not typically tested | 270–330 HV10 typical | 40–45 FN |
Oil and gas specifications typically require Charpy testing at −46°C or −50°C for super duplex deposits. NACE MR0175/ISO 15156 mandates 30–70 vol% ferrite per ASTM E562 and hardness ≤32 HRC. Higher ferrite, typical of FCAW (vs GTAW) makes heat input control critical.
Base Metal Compatibility and ASME P-Number Matrix for E2594T1-1/T1-4
E2594T1 is designed for super duplex base metals and qualifies for dissimilar combinations and root runs on standard duplex pipe.
| Joint Type | Base Metal(s) | ASME P-Number | Notes |
|---|---|---|---|
| 2507 to 2507 | UNS S32750 | P-10H Grp 1 | Primary application: all positions, as-welded |
| Zeron 100 to Zeron 100 | UNS S32760 | P-10H Grp 1 | W + Cu bearing super duplex |
| Ferralium 255 to Ferralium 255 | UNS S32550 | P-10H Grp 1 | Not for H₂SO₄ / sulphurous acid service |
| Cast super duplex | J93380 / J93404 | P-10H Grp 1 | Cast equivalents of 2507 / Zeron 100 |
| DP-3 to DP-3 | UNS S31260 | P-10H Grp 1 | Lower Mo super duplex variant |
| Super Duplex to Duplex 2205 | P-10H to P-10H | P-10H | Over-alloyed deposit improves root corrosion resistance |
| Super Duplex to 316L/304L | P-10H to P-8 | P-10H / P-8 | Control dilution from austenitic side |
| Super Duplex to Carbon Steel | P-10H to P-1 | P-10H / P-1 | Clad pipe tie-ins, subsea connectors: strict dilution control |
| Standard Duplex 2205 root runs | UNS S32205 | P-10H Grp 1 | Enhanced corrosion resistance at the root |
Caution: Do not use E2594T1 on Ferralium (S32550) in sulphuric or sulphurous acid service. Cu content may not be compatible with H₂SO₄ environments.
Recommended Welding Parameters for E2594T1-1/T1-4
Heat input control is more critical for super duplex than standard duplex. The narrower processing window demands tight parameters to prevent sigma (σ) and chi (χ) phase precipitation and maintain ferrite-austenite balance.
| Diameter | Position | Amperage (A) | Voltage (V) | Shielding Gas |
|---|---|---|---|---|
| 1.2 mm (0.045”) | Flat / Horizontal | 160–220 | 25–30 | CO₂ or 75%Ar/25%CO₂ |
| 1.2 mm (0.045”) | Vertical-Up | 140–180 | 24–27 | 75%Ar/25%CO₂ recommended |
| 1.2 mm (0.045”) | Overhead | 140–180 | 24–27 | 75%Ar/25%CO₂ |
| 1.6 mm (1/16”) | Flat / Horizontal | 170–305 | 25–29 | CO₂ or 75%Ar/25%CO₂ |
Optimum CTWD: 20 mm (3/4”). Heat input: 0.4–1.2 kJ/mm (10–30 kJ/in), narrower than standard duplex (0.5–2.5 kJ/mm) due to higher sigma phase susceptibility. Interpass temperature: 150°C (302°F) max. No preheat unless the base metal is below 5°C. With Ar/CO₂, reduce voltage by ~2V vs CO₂. Formula: HI (kJ/mm) = (A × V × 60) / (Travel Speed mm/min × 1000).
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Industrial Welding Applications of E2594T1-1/T1-4 Super Duplex Flux Cored Wire
E2594T1-1/T1-4 serves the most demanding corrosion environments where standard duplex E2209T1 falls short on pitting or SCC resistance. These are applications where PREN >40 weld metal is a mandatory requirement.
- Welding super duplex manifolds, subsea trees, risers, and flowline spools in high-chloride produced fluids with H₂S.
- Super duplex 2507 is standard for high-pressure pump bodies, seawater intake piping, and brine recirculation in RO/MSF/MED plants.
- FGD scrubbers, chlorine production cells, and bleach plant equipment need PREN >40 fillers due to high temperature and chloride/acid exposure.
- Super duplex replaced 6Mo austenitic alloys in aggressive bleach plant service. E2594T1 welds super duplex digesters, ClO₂ generators, and bleach washers.
- Nuclear seawater cooling intake piping and condensers use super duplex for long design life in high-chloride seawater.
Storage, Handling, and Moisture Control for E2594T1-1/T1-4
Super duplex weld metal carries higher ferrite than standard duplex, making it more susceptible to hydrogen-assisted cracking from moisture. Storage discipline is non-negotiable.
Keep spools in original vacuum-sealed packaging until use. Store at 10–40°C, below 50% RH. Opened spools go in heated cabinets at 40–50°C or resealed with desiccant. Vacuum-sealed shelf life is 2 years; opened spools are used within 7 days at ambient or 6 months in a heated cabinet. Reconditioning is not recommended. Discard and replace if moisture is suspected. Handle with clean, dry gloves and avoid oil or grease contamination.
Available Forms and Packaging for E2594T1-1/T1-4
At Nicorex Alloys, we stock E2594T1-1/T1-4 in various forms, diameters, and packaging options:
| Form | Diameter | Packaging |
|---|---|---|
| Spool | 1.2 mm (0.045″) | 5 kg, 12.5 kg (D300), 15 kg (33 lb), 20 kg, 25 lb, 28 lb |
| Spool | 1.6 mm (1/16″) – limited availability, flat/horizontal work only | 5 kg, 12.5 kg (D300), 15 kg (33 lb), 20 kg, 25 lb, 28 lb |
| Coil | 1.2 mm (0.045″) | 60 lb |
| Round Drum | 1.2 mm (0.045″) | 500 lb |
| Hex Drum | 1.2 mm (0.045″) | 800–900 lb |
All packaging is vacuum-sealed with desiccant. Labels carry AWS classification, heat/lot number, diameter, and approval marks.
How to Order E2594T1-1/T1-4 Super Duplex Flux Cored Wire from Nicorex Alloys
Nicorex Alloys supplies E2594T1-1/T1-4 from stock in Mumbai with nationwide and international delivery. For a quotation, provide the following details:
- Wire Type — FCAW-G Tubular Wire for Super Duplex Stainless Steel (E2594T1-1 / T1-4)
- Size — 1.2mm / 1.6mm — 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
- Material Grade — Super Duplex FCAW Wire / UNS S32760 / AWS A5.22: E2594T1-1/T1-4 / W.Nr. 1.4501
- Quantity — Number of spools or total weight in kg
- Standard — AWS A5.22 / ASME SFA 5.22, EN ISO 17633-A: T 25 9 4 N L, ASME Section IX
- Additional Requirements — PREN ≥ 40, ferrite content (40–55% FN), NACE, PMI, heat/lot traceability
- Documentation — MTC 3.1/3.2, PMI Report, FN Report, Weld Metal Composition Report, TPI Certificate
- Delivery — Domestic / International (specify destination)
Complete super duplex consumable sets available from a single source: E2594T1-1/T1-4 (FCAW) + ER2594 (GTAW/GMAW) + E2594-16 (SMAW).
Frequently Asked Questions
What is the Minimum PREN required for a Super Duplex Weld Deposit, and does E2594T1 meet it?
The industry minimum PREN for super duplex weld metal is 40, calculated as %Cr + 3.3 × (%Mo + 0.5 × %W) + 16 × %N. E2594T1-1/T1-4 deposits consistently achieve 41–42 with both CO₂ and Ar/CO₂ shielding, comfortably exceeding the threshold.
Can E2594T1-1/T1-4 be used for Root Pass Welding on Standard Duplex 2205 Pipe?
Yes: E2594T1 can weld root passes on duplex 2205 (UNS S32205) pipe. The over-alloyed deposit provides enhanced corrosion resistance at the root, the most vulnerable location. Impact toughness may be slightly lower than E2209T1 on duplex base metal; use E2209T1 if low-temperature toughness is the primary concern.
Why is the Heat Input Range for E2594T1 Narrower Than for E2209T1?
Super duplex steels have higher Cr and Mo, making them more prone to sigma (σ) and chi (χ) phase precipitation during slow cooling. These brittle phases destroy toughness and corrosion resistance. E2594T1’s recommended heat input is 0.4–1.2 kJ/mm vs 0.5–2.5 kJ/mm for E2209T1, demanding shorter beads and more frequent interpass checks.
What ASTM G48 Corrosion Test Requirements Apply to E2594T1 Weld Deposits?
Most offshore specifications require E2594T1 deposits to pass ASTM G48 Method A (pitting) at a minimum of 40°C. Stricter specifications add Methods B and E (crevice corrosion) at 40°C. Achieving these results requires correct heat input, interpass ≤150°C, and proper ferrite balance.
What is the Ferrite Range Difference Between E2594T1 Welded With CO₂ Versus Ar/CO₂ Gas?
Shielding gas significantly impacts ferrite. 100% CO₂ produces 40–45 FN (lower), while 75–80%Ar/20–25%CO₂ produces 55–60 FN (higher). CO₂ is more oxidising, promoting nitrogen retention that stabilises austenite and lowers ferrite. Both options typically meet NACE MR0175’s 30–70 vol% requirement, but Ar/CO₂ needs closer monitoring of the upper limit.
Does E2594T1-1/T1-4 Require Post-Weld Heat Treatment?
No. PWHT is not required and is actively discouraged. Heating to 300–1000°C risks sigma, chi, and 475°C embrittlement phases that destroy toughness and corrosion resistance. E2594T1 is designed for as-welded service.
What Spool Sizes are Available for E2594T1-1/T1-4 Flux Cored Wire?
Standard sizes include 5 kg, 12.5 kg (D300), 15 kg (33 lb), 20 kg, 25 lb, and 28 lb spools. Bulk options include 60 lb coils and 500–900 lb drums. The 1.2 mm diameter is stocked across all sizes; 1.6 mm has limited availability on larger spools for flat-position work.
Can E2594T1-1/T1-4 be used with Self-Shielded (No Gas) Operation?
No. E2594T1-1/T1-4 is a gas-shielded wire (FCAW-G) requiring external shielding gas at all times. Running without gas causes severe porosity, nitrogen loss, ferrite imbalance, and catastrophic corrosion resistance loss. No self-shielded (FCAW-S) classification exists for super duplex consumables.