- Home
- Welding Consumables
- 25/35 Welding Wire
25/35 Welding Wire Supplier - Heat Resistant HP Mod 25Cr-35Ni-Nb Filler | W.Nr. 1.4853
Nicorex Alloys is an ISO 9001 and ISO 14001 certified supplier and stockist of 25/35 welding wire classified under AWS A5.9 based in Mumbai, India. Also sold as Thermanit 25/35 R and UTP A 2535 Nb, this heat-resistant filler wire carries W.Nr. 1.4853 and falls under EN 12072 (W2535) and DIN 17465 (SG-X NiCrNb 35 25).
This weld metal contains about 25.8% chromium, 35.2% nickel, 1.32% niobium and 0.43% carbon. These elements form a strong niobium‑carbide network that helps ethylene crackers and steam methane reformers run for long hours at 900-1050°C (1652-1922°F). The high carbon level is intentional. It creates Cr₂₃C₆ and NbC carbides that give the weld excellent creep strength at very high temperatures. Typical weld metal has a tensile strength of 600 MPa (87 ksi), a yield strength of 403 MPa (58.5 ksi) and 8% elongation. This low elongation is normal for this alloy and results from its dense carbide network.
25/35R filler wire welds HP-type castings per ASTM A297, DIN 17465 and ISO 11973, and is also compatible with HK40 and Nb-free alloy castings. Resistance to creep, oxidation, carburisation and scaling makes it a good choice for the petrochemical sector. Available as TIG rods (2.4 mm and 3.2 mm × 1000 mm) and MIG wire (0.9 mm and 1.14 mm spools). This welding wire is used to join heat‑resistant nickel‑chromium alloys in furnace components, petrochemical reformer tubes, heat‑treating systems and other high‑temperature parts exposed to carburising and oxidising conditions.Every shipment includes EN 10204/3.1B mill test certificates and full traceability.
25/35 Welding Wire Specifications
Specifications for 25/35 welding wire include its classification, supported welding processes, available wire diameters and required shielding gases.
| Classification | EN 12072 W2535 / DIN 17465 SG-X NiCrNb 35 25 |
|---|---|
| Werkstoff Nr. | 1.4853 |
| Welding Processes | GTAW (TIG), GMAW (MIG/MAG) |
| TIG Rod Diameters | 2.4 mm (3/32″) and 3.2 mm (1/8″) × 1000 mm |
| MIG Wire Diameters | 0.9 mm (0.035″) and 1.14 mm (0.045″) |
| Shielding Gas | GTAW: 100% Argon GMAW: 75Ar/25He, 98Ar/2CO₂, 90He/7.5Ar/2.5CO₂ |
Understanding the 25/35 Designation
The 25/35 designation explains the chromium, nickel, and niobium content in this welding filler wire.
| Component | Meaning | Function / Purpose |
|---|---|---|
| 25 | 25% Chromium (Cr) | Provides oxidation and sulfidation resistance at high temperatures. |
| 35 | 35% Nickel (Ni) | Provides a stable austenitic structure and resistance to carburization. |
| Nb Carbides | Microstructural Stability | Forms NbC carbides for creep strength. |
Weld Deposit Chemical Composition
Typical 25/35R weld deposit chemistry is shown below, listing the percentage of each major alloying element in the weld metal.
| Element | Carbon (C) | Manganese (Mn) | Silicon (Si) | Chromium (Cr) | Nickel (Ni) | Niobium (Nb) | Copper (Cu) | Phosphorus (P) | Sulphur (S) |
|---|---|---|---|---|---|---|---|---|---|
| Composition (%) | 0.43 | 1.74 | 1.1 | 25.8 | 35.2 | 1.32 | 0.03 | 0.010 | 0.003 |
The 0.43% carbon is added on purpose. In heat‑resistant alloys, carbon is useful because it forms Cr₂₃C₆ and NbC carbides, which give the weld strength to resist creep above 900°C.
Niobium at 1.32% creates stable NbC carbides that stay effective over decades of service. Silicon at 1.1% further improves oxidation and carburisation resistance, helping the weld survive long‑term high‑temperature operation.
All-Weld-Metal Mechanical Properties
Mechanical properties of the 25/35R weld deposit reflect its creep-optimised, carbide-rich microstructure. Tensile and yield strength, and elongation values are covered in the table below:
| Property | Tensile Strength | Yield Strength (0.2% Offset) | Elongation |
|---|---|---|---|
| Value | 600 MPa (87,000 psi) | 403 MPa (58,500 psi) | 8% |
An 8% elongation value is normal for 25/35 welds. This wire is designed for high creep strength at 900-1050°C, not for flexibility at room temperature. A dense network of NbC and Cr₂₃C₆ carbides gives the weld long-term strength but reduces ductility.
Get 25/35 Welding Wire at Competitive Prices
Industrial Applications
25/35 heat-resistant filler wire is mainly used in two petrochemical applications. In both, a tube failure can cause an unexpected shutdown and cost the plant millions in lost production.
-
Petrochemical - Reformer Tubes: HP Mod cast tubes depend on 25/35R filler wire to create welds with creep strength equal to the tube material.
-
Ethylene - Pyrolysis Coils:The Nb-stabilised 25/35R deposit provides the creep rupture and carburisation resistance needed at these extreme operating temperatures.
Available Forms & Packaging
Nicorex Alloys stocks 25/35 welding wire in the following TIG rod and MIG spool configurations.
| Form | Diameter | Length / Spool | Packaging |
|---|---|---|---|
| TIG Rod | 2.4 mm (3/32″) | 1000 mm (39″) | 4.5 kg (10 lb) tube |
| TIG Rod | 3.2 mm (1/8″) | 1000 mm (39″) | 4.5 kg (10 lb) tube |
| MIG Wire | 0.9 mm (0.035″) | Spool | 15 kg (33 lb) spool |
| MIG Wire | 1.14 mm (0.045″) | Spool | 15 kg (33 lb) spool |
How to Order 25/35 Welding Wire from Nicorex Alloys
To place an order, provide the following details:
- Wire / Electrode Type: GMAW/GTAW wire, EN 12072 W2535
- Size (in mm rods)
- Current Type: DCEN TIG; DCEP MIG
- Welding Position: Flat, horizontal, vertical, overhead
- Material Grade: NiCrNb 25/35, W2535, W.Nr. 1.4853
- Quantity: Spools or rod tubes, kg basis
- Standard: EN 12072, DIN 17465
- Documentation: EN 10204 3.1 MTC, chemistry report
- Packaging: Spools, vacuum foil bag, rods and tubes
- Delivery Destination: Domestic/International.
Frequently Asked Questions - 25/35 Welding Wire
What is the price of 25/35 Welding Wire per kg in India?
25/35 price per kg depends on the wire size, order quantity and market conditions. Contact Nicorex Alloys for current prices and bulk discounts.
Why does 25/35 have such high carbon (0.43%)?
The 0.43% carbon is added on purpose. It forms Cr₂₃C₆ and NbC carbides that create the strength needed to resist creep at 900–1050°C. In heat‑resistant alloys, carbon is helpful.
Is 8% elongation normal for 25/35 Welds?
Yes. The 8% elongation is due to the dense carbide network in the weld metal. The 25/35 wire is designed for high creep strength at temperature, not for high ductility. This behaviour is normal for HP-type heat-resistant fillers.
Does 25/35 have an AWS Classification?
No. 25/35 filler wire does not have an AWS classification. It is classified under EN 12072 (W2535) and DIN 17465.
What is the difference between 25/35 and 21/33 Welding Wire?
25/35 contains more chromium, nickel, and much higher carbon than 21/33. Because of this, 25/35 is used for HP-type reformer tubes and pyrolysis coils, while 21/33 is used for Alloy 800H and CT15C castings. 25/35 has lower ductility but delivers higher strength and creep resistance at extreme temperatures.
What is the Thermanit trade name for 25/35?
The Thermanit trade name for 25/35 is Thermanit 25/35 R. The “R” means it is the niobium-stabilised (Nb-stabilised) version.