AWS Class E309LT1-1/T1-4 Flux Core
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E309LT1-1/T1-4 Stainless Steel Flux Cored Wire Supplier in Mumbai, India
Nicorex Alloys is an ISO 9001 and ISO 14001 certified stockist and supplier of E309LT1-1/T1-4 stainless steel flux cored wire based in Mumbai, India. We provide this SS flux core wire classified under AWS A5.22 and ASME SFA 5.22.
E309LT1-1/T1-4 flux cored wire is the transition filler that compensates for dilution and delivers a crack-free, corrosion-resistant deposit. This gas-shielded rutile-type tubular wire carries dual designations: E309LT1-1 for 100% CO2 shielding and E309LT1-4 for 75-80% Ar / 20-25% CO2 mixed gas (UNS W30931 / W30935). The high 23% chromium and 12% nickel levels compensate for iron dilution from the carbon steel side, so the fusion zone stays fully austenitic. Tensile strength meets the 520 MPa (75,000 psi) AWS minimum, with typical values of 83,000–90,000 psi and at least 30% elongation. Typical ferrite content sits at 15-18 FN for strong resistance to solidification cracking. Available diameters are 0.9 mm (0.035″), 1.2 mm (0.045″), and 1.6 mm (1/16″). Welding runs on DCEP in all positions.
Compatible base metals include carbon steel (P-1) to stainless (P-8), low-alloy steel (P-3/P-4) to stainless, and 12% Cr martensitic (P-6). The cored electrode also serves as a buffer layer for stainless cladding on carbon steel before capping with E308LT1 or E316LT1. Industries served span oil and gas, petrochemical, power generation, pulp and paper, construction and shipbuilding. Every spool ships with MTC 3.1 per EN 10204.
E309LT1-1/T1-4 Flux Cored Wire Specifications
The following technical specifications and code classifications apply to E309LT1-1/T1-4 gas-shielded stainless steel flux-cored wire:
| AWS Specification | AWS A5.22/A5.22M:2012 |
|---|---|
| ASME SFA Specification | SFA 5.22 |
| UNS Number | W30931 (T1-1) / W30935 (T1-4) |
| Welding Process | FCAW-G (Gas Shielded) |
| Flux Type | Rutile (Titania-based) |
| Polarity / Current | DCEP (DC Electrode Positive) |
| Welding Positions | All positions (Flat, Horizontal, Vertical-Up, Overhead) |
| Shielding Gas (T1-1) |
T1-1: 100% CO2, flow rate 35-50 cfh (15-25 L/min) T1-4: 75-80% Ar / 20-25% CO2, flow rate 35-50 cfh (15-25 L/min) |
| Available Diameters | 0.9 mm (0.035″), 1.2 mm (0.045″), 1.6 mm (1/16″) |
| CTWD (Electrode Stickout) | 15-30 mm (5/8″ to 1-1/4″) |
| Spool Sizes | 5 kg, 12.5 kg (28 lb), 15 kg (33 lb) |
| Deposition Efficiency | ~80-88% |
| Ferrite Number (Typical) | 15-18 FN (WRC-1992) |
Understanding the AWS A5.22 Designation: E309LT1-1 vs E309LT1-4
The AWS A5.22 code is a short letter-number label that shows the weld metal chemistry, welding positions, and required shielding gas. For welding engineers, every character in this code has a clear and specific meaning.
| Designator | Meaning |
|---|---|
| E | Electrode – carries welding current to the arc |
| 309L | Weld deposit: 23Cr-12Ni low-carbon type. “L” = ≤0.04% C. Higher Cr/Ni than 308L compensates for dilution in dissimilar joints. |
| T | Tubular electrode (flux cored wire) |
| 1 | All-position capable (flat, horizontal, vertical-up, overhead). “0” = flat/horizontal only. |
| -1 | Shielding gas: 100% CO2 |
| -4 | Shielding gas: 75-80% Ar / 20-25% CO2 mix |
309L has about 5% more chromium and 3% more nickel than 308L. After 15-25% dilution by carbon steel, it still gives about 18Cr-10Ni, similar to 304 stainless. Using E308LT1 instead would drop Cr and Ni too low, forming a brittle, crack‑prone zone. Shielding gas selection remains essential under ASME Section IX QW-408.
Chemical Composition of E309LT1 Weld Deposit (%)
The chemical composition of E309LT1 weld deposit is deliberately over-alloyed relative to standard 18Cr-8Ni grades. When this deposit mixes with iron-rich carbon steel through dilution, the resulting chemistry stays within the austenitic range.
| Property | Tensile Strength | Yield Strength (0.2%) | Elongation (%) | Reduction of Area (%) | Ferrite Number (FN) | Charpy V-Notch +20°C | Charpy V-Notch -20°C |
|---|---|---|---|---|---|---|---|
| AWS A5.22 Requirement | ≥75,000 psi (520 MPa) | Not specified by AWS | ≥35% | Not specified | Not specified (3-20 FN rec.) | Not required by AWS | Not required by AWS |
| Typical (75/25 Ar/CO2) | 88,600 psi (611 MPa) | 67,750 psi (467 MPa) | 38% | — | 10-12 FN | 60 J | 51 J |
| Typical (100% CO2) | 77,883 psi (537 MPa) | 59,062 psi (407 MPa) | 42% | 49% | 8-9 FN | — | — |
In a typical dissimilar joint with 15-25% dilution from carbon steel, effective chromium drops to approximately 17-20% and nickel to 9-11%, matching a 304-type composition. This dilution-compensated chemistry is the fundamental reason E309L fillers are specified over E308L for every stainless-to-carbon steel transition joint.
All-Weld-Metal Mechanical Properties of E309LT1 Deposit
In dissimilar metal joints, the weld deposit must bridge two base metals with different strength levels. The following all-weld-metal properties, tested as-welded per AWS A5.22, exceed both carbon steel and stainless steel base metal minimums.
| Property | Tensile Strength | Yield Strength (0.2%) | Elongation (%) | Ferrite Number (FN) | Charpy V-Notch +20°C | Charpy V-Notch -20°C |
|---|---|---|---|---|---|---|
| AWS A5.22 Requirement | ≥75,000 psi (520 MPa) | Not specified | ≥30% | Not specified | Not required | Not required |
| Typical (75/25 Ar/CO2) | 86,000-90,000 psi (593-620 MPa) | 60,000-65,000 psi (414-448 MPa) | 34-36% | 15-18 FN | ~60 J | ~50 J |
| Typical (100% CO2) | 82,000-83,600 psi (565-576 MPa) | 59,062 psi (407 MPa) | 41% | 12-15 FN | — | — |
The E309LT1 deposit overmatches typical P-1 carbon steel in both strength and ductility while providing corrosion resistance. Higher ferrite than E308LT1 reduces solidification cracking risk at the stainless/carbon steel interface, where residual stress concentrations are common.
Base Metal Compatibility & Dissimilar Joint P-Number Matrix for E309LT1
E309LT1-1/T1-4 is the standard filler for joining dissimilar base metals where at least one side is austenitic stainless steel and the other is carbon or low-alloy steel.
Table 1 – Dissimilar Metal Joint Combinations (Primary Use):
| Joint Configuration | Base Metal A (P-No.) | Base Metal B (P-No.) | Application |
|---|---|---|---|
| Stainless to Carbon Steel | P-8 (304, 304L, 316L) | P-1 (A36, A516 Gr 70) | Complete joint or transition layer |
| Stainless to Low-Alloy | P-8 (304, 304L) | P-3/P-4 (1Cr-0.5Mo) | Transition layer; cap with E308LT1 |
| Stainless to CrMo | P-8 (304, 304L) | P-5A (2.25Cr-1Mo) | Butter CS side with E309LT1, cap with SS filler |
| 12Cr to Austenitic | P-6 (Type 410, 405) | P-8 (304, 304L) | Without PWHT when preheat is controlled |
| Clad Steel Groove | P-8 cladding | P-1 backing | E309LT1 first layer to restore the clad groove |
Table 2 – Overlay / Cladding Applications:
| Substrate | Overlay Purpose | Notes |
|---|---|---|
| Carbon steel (P-1) | First layer stainless cladding | Cap with E308LT1 or E316LT1 |
| Low-alloy steel (P-3/P-4/P-5A) | Transition layer for corrosion protection | E309LT1 acts as a diffusion barrier |
| 12Cr ferritic/martensitic (P-6) | Austenitic overlay | Accommodates Cr dilution from 12% base |
E309LT1-1/T1-4 is classified as F-No. 6 and A-No. 8 in ASME Section IX, so requalification is not required when changing fillers within F-6. Do not use E309LT1 for similar-metal P-8 joints; always select E308LT1 instead.
Recommended Welding Parameters for E309LT1-1/T1-4
Dissimilar joints require controlled heat input to minimise dilution and prevent carbon migration from the carbon steel side. The following parameters balance penetration, deposition rate and dilution control on DCEP with a gas flow of 35-50 cfh (16-24 L/min).
| Diameter | Position | Wire Feed (ipm) | Current (A) | Voltage (V) | CTWD |
|---|---|---|---|---|---|
| 0.035″ (0.9 mm) | Flat / Horizontal | 365 | 130-140 | 24-25 | 1/2-3/4″ |
| 0.035″ (0.9 mm) | Vertical-Up | 310 | 110-120 | 22-23 | 1/2-3/4″ |
| 0.035″ (0.9 mm) | Overhead | 320 | 120-130 | 23-24 | 1/2-3/4″ |
| 0.045″ (1.2 mm) | Flat / Horizontal | 215-550 | 140-380 | 23-35 | 1/2-1″ |
| 0.045″ (1.2 mm) | Vertical-Up | 325 | 150-170 | 24-26 | 5/8-3/4″ |
| 0.045″ (1.2 mm) | Overhead | 425 | 175-195 | 25-27 | 5/8-3/4″ |
| 1/16″ (1.6 mm) | Flat / Horizontal | 125-615 | 150-410 | 24-36 | 5/8-1.25″ |
| 1/16″ (1.6 mm) | Vertical-Up | 220 | 190-210 | 25-26 | 5/8-3/4″ |
| 1/16″ (1.6 mm) | Overhead | 235 | 200-220 | 25-26 | 5/8-3/4″ |
Preheat is not required on the stainless side. For the carbon steel side, preheat per code (10-150°C depending on carbon equivalent and thickness). For 12Cr martensitic base metals, preheat 150-250°C. Maximum interpass: 175°C (350°F). For cladding, aim for 15-20% max dilution on the first pass using stringer beads with 30-50% overlap. If PWHT is mandated, limit to ≤620°C (1150°F) to prevent sigma phase.
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Dissimilar Joint & Cladding Applications of E309LT1-1/T1-4 Across Industries
E309LT1-1/T1-4 FCAW wire serves every industry where carbon steel structures require stainless steel corrosion protection through overlay cladding or where dissimilar metal transitions are unavoidable.
- Oil & Gas - Transition Joints in Process PipingDissimilar joints at heat exchanger nozzles and reactor inlets rely on E309LT1 to bridge P-1 and P-8 piping.
- Petrochemical & Refinery - Clad Vessel Fabrication: Stainless-clad carbon steel pressure vessels are standard in refinery service. E309LT1 welds the first cladding layer on the carbon steel shell before E308LT1 or E316LT1 cap layers restore the corrosion-resistant surface. Also used for clad-side groove restoration during turnarounds.
- Power Generation - HRSG & Boiler Transition Welds: HRSGs and conventional boilers use dissimilar metal welds where superheater tubes transition from ferritic/CrMo alloys to austenitic stainless. E309LT1 provides the metallurgical bridge.
- Pulp & Paper - Digester Lining & Clad Repairs: Carbon steel digesters with stainless internal lining need periodic overlay repair when corrosion damages the clad surface. E309LT1 restores the transition layer and FCAW speeds turnaround work.
- Construction & Infrastructure - Stainless-to-Structural Steel Connections: Handrail brackets on stainless-clad bridges, facade panels attached to steel frames and expansion joint connections in stainless-lined tunnels and water channels are welded per AWS D1.6.
- Shipbuilding & Offshore - Stainless Equipment on Carbon Steel Hulls: Marine applications where stainless process equipment is attached to carbon steel hull structures use E309LT1 for the transition joint. Also used for stainless cladding of ballast tank internals and seawater piping flanges.
Storage & Handling Requirements for E309LT1 Flux Cored Wire
Flux core wire performance is directly linked to moisture control.
- Store sealed spools at 15-25°C (59-77°F) with humidity below 60%, elevated from the floor.
- After opening the vacuum seal, use within 1-2 weeks or transfer to a heated cabinet at 40-50°C (100-120°F).
- Unlike SMAW electrodes, flux-cored wire cannot be re-dried by baking. Prevention through storage is the only approach.
- Handle spools with clean, dry gloves and inspect wire surfaces for rust.
Porosity in dissimilar weld deposits creates preferential corrosion at the stainless/carbon steel interface. Strict moisture control is a quality-critical activity.
Nicorex Alloys supplies spools in vacuum-sealed moisture-barrier packaging. Individually wrapped spools within cardboard cartons.
How to Order E309LT1-1/T1-4 Flux Cored Wire from Nicorex Alloys
Nicorex Alloys supplies E309LT1-1/T1-4 from ready stock in Mumbai with delivery across India and export capability. Include the following details in your order:
- Wire Type - FCAW-G Tubular Wire for Dissimilar & Buffer Layer Welding (E309LT1-1 / T1-4)
- Size - 0.9 mm / 1.2 mm / 1.6 mm
- Shielding Gas - T1-1: 100% CO₂ / T1-4: 75–80% Ar + 20–25% CO₂ — specify suffix
- Current Type - Specify wire feed speed and voltage per diameter
- Welding Position - All Positions (1G–6G)
- Material Grade - Low Carbon Austenitic FCAW Wire / UNS S30988 / AWS A5.22: E309LT1-1/T1-4 / W.Nr. 1.4332
- Quantity - Number of spools or total weight
- Standard - AWS A5.22 / ASME SFA 5.22, EN ISO 17633-A: T 23 12 L, ASME Section IX
- Additional Requirements - Ultra-low carbon (C ≤ 0.03%), Ferrite Number (FN 8–20), dissimilar / overlay suitability, PMI, heat / lot traceability
- Delivery - Domestic / International
Frequently Asked Questions
Why must E309LT1 be used instead of E308LT1 for Stainless-to-Carbon Steel Joints?
When E308LT1 (18Cr-8Ni) is deposited on a carbon steel joint, iron dilution reduces Cr and Ni below stable austenitic levels, creating a brittle martensitic zone prone to cracking. E309LT1 (23Cr-12Ni) provides enough headroom so that after 15-25% dilution, the fusion zone retains ~18Cr-10Ni.
Does Nicorex Alloys Supply E309LT1 with DNV, ABS, or Lloyd's register approval?
Yes. Nicorex Alloys is a distributor of E309LT1-1/T1-4 with approvals from DNV GL, ABS, Lloyds Register, Bureau Veritas, TÜV, CWB and CE Mark.
What is the Typical Ferrite content of E309LT1, and why is it higher than E308LT1?
E309LT1 has higher ferrite (15-18 FN vs 8-12 FN in E308LT1) due to its 23Cr-12Ni composition, which better resists solidification cracking under high stresses in carbon steel joints.
Can E309LT1-1/T1-4 be used as the Sole Filler for a complete Stainless-to-Carbon Steel Joint?
For structural or non-corrosion-critical joints, E309LT1 can serve as the sole filler for root, fill, and cap passes. For aggressive media (chlorides, acids), cap the final layer with E308LT1 or E316LT1 to meet process corrosion requirements.
When not to use E309LT1-1/T1-4 Flux Cored Wire
E309LT1 should not be used for similar austenitic stainless joints like 304/304L or 316/316L, as its high ferrite reduces corrosion resistance. Use E308LT1 for 304/304L and E316LT1 for 316/316L. Do not use it as a cap in aggressive service.