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21/33 Welding Wire Supplier — Heat Resistant 21Cr-33Ni Filler | W.Nr. 1.4850 | DIN 8556
Nicorex Alloys is an ISO 9001 and ISO 14001 certified Mumbai-based supplier and stockist of 21/33 welding wire, the matching filler metal for Alloy 800/800H (UNS N08810/N08811). We provide these wires classified under DIN 8556 and under EN ISO 14343-A.
The 21/33 filler wire is a heat-resistant welding wire designed for long-term use at high temperatures up to 1050°C (1922°F). Its weld deposit contains about 21% chromium, 34% nickel, and 1.2% niobium, giving it excellent strength and creep resistance at elevated temperatures. The wire corresponds to Werkstoff Number 1.4850. 21/33 produces a fully austenitic weld metal with zero ferrite. Because of this, welding must be done carefully using stringer beads only, with low heat input and interpass temperatures kept below 175°C (350°F) to reduce the risk of cracking. This wire is primarily used for GTAW (TIG) welding with 100% argon shielding gas. Standard diameters range from 1.6 to 3.2 mm (1/16–1/8″), supplied in 1000 mm straight lengths. Typical all-weld-metal properties are: tensile strength 603 MPa (87,500 psi), yield strength 383 MPa (55,500 psi), and 20% elongation.
It is mainly used in applications that include steam methane reformer tube welds, ethylene cracker tube supports, pyrolysis furnace internals, and heat treatment fixtures in carburising atmospheres. Every shipment from Nicorex Alloys includes EN 10204/3.1B mill test certificates, PMI reports, and full lot traceability.
21/33 Welding Wire Specifications
The table below lists the key specifications, welding parameters, and dimensions for this heat-resistant grade 21/33 welding wire.
| Classification | DIN 8556 SG-X15 NiCrNb 32 21 / EN ISO 14343-A WZ 21 33 Mn Nb |
|---|---|
| Polarity | DCEN (straight polarity) |
| Welding Positions | All positions |
| TIG Diameters | 1.6, 2.4, 3.2 mm (1/16″, 3/32″, 1/8″) |
| Cut Length | 1000 mm |
| MIG Availability | Limited — primarily a GTAW product |
| Shielding Gas | 100% Argon |
Understanding the 21/33 Designation
21/33 welding wire is a 21% chromium, 33% nickel heat-resistant filler metal for high-temperature Alloy 800/800H applications.
| Item / Concept | Details |
|---|---|
| Meaning of “21” | Refers to the nominal chromium content: 21% Cr |
| Meaning of “33” | Refers to the nominal nickel content: 33% Ni |
Weld Deposit Chemical Composition of 21/33
The weld deposit chemistry of 21/33 determines the alloy’s creep strength and oxidation behaviour at high temperatures.
| Element | C | Si | Cr | Mn | Ni | Nb | Ti | Al | N | Mo | P | S | Cu | Fe |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wt % | 0.12 | 0.20 | 21.0 | 4.8 | 34.0 | 1.2 | 0.22 | 0.12 | 0.02 | 0.01 | 0.005 | 0.008 | 0.02 | Balance |
Niobium at 1.2% is the defining addition. Nb forms stable NbC carbides that anchor the microstructure during prolonged exposure above 800°C, providing the creep strength that standard austenitic fillers lack.
High manganese at 4.8% keeps the deposit fully austenitic with zero ferrite, which is critical for high-temperature ductility. Moderate carbon at 0.12% supports carbide formation for creep resistance
All-Weld-Metal Mechanical Properties
Mechanical properties of 21/33 welding wire, including tensile and yield strength, elongation, and more, are covered in the table below:
| Property | Tensile Strength | Yield Strength (0.2% Offset) | Elongation | Charpy V-Notch at 20°C |
|---|---|---|---|---|
| Value | 603 MPa (87,500 psi) | 383 MPa (55,500 psi) | 20% | 41 J (30 ft-lbs) |
The 20% elongation is lower than that of typical austenitic filler metals (35–40%) because the higher carbon and niobium (Nb) levels are designed to improve creep strength at high temperatures, not flexibility at room temperature.
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Industrial Applications
21/33 welding wire is mainly used in two areas: petrochemical processing and heat treatment furnace fabrication. Both require filler metals that can work above 800°C.
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Petrochemical: Steam methane reformer tubes, ethylene cracker tube supports, and pyrolysis furnace internals.
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Heat Treatment Furnace Equipment: Fixtures, trays, baskets, muffles, and radiant tubes for bright annealing and carburising furnaces.
Available Forms & Packaging
| Form | TIG straight lengths | MIG spool (GMAW) |
|---|---|---|
| Diameter | 1.6, 2.4, 3.2 (mm) | 0.8, 1.0, 1.2, 1.6 (mm) |
| Packaging | 10 lb tubes; 60 lb cartons | 33 lb (15 kg) spool |
How to Order 21/33 Welding Wire from Nicorex Alloys
To order 21/33 Welding Wire from Nicorex Alloys, provide these 10 important details:
- Wire Type: Solid GTAW / GMAW Wire for Welding Heat-Resistant Austenitic and Nickel-Iron-Chromium Alloys (21% Cr / 33% Ni)
- Size: Diameter: 1.6mm / 2.0mm / 2.4mm / 3.2mm (GTAW cut lengths) / 0.9mm / 1.2mm (GMAW spools)
- Current Type: DCEN (TIG / GTAW) / DCEP (MIG / GMAW)
- Welding Position: All Positions
- Material Grade: Nickel-Iron-Chromium Alloy Welding Wire / ~21% Cr, ~33% Ni
- Quantity: Number of spools/packs or total weight in kg
- Standard: EN ISO 18274
- Documentation: MTC EN 10204 3.1/3.2, PMI Report, Weld Metal Composition Report, Mechanical Properties Report, TPI Certificate
- Packaging: Vacuum-sealed moisture-proof foil bag with silica gel desiccant, ISPM 15-compliant export cartons with full labelling
- Delivery Destination: Domestic
Frequently Asked Questions — 21/33 Welding Wire
What base metals can 21/33 Wire Weld?
Alloy 800, 800H, and 800HT (UNS N08810/N08811) are the primary base metals that 21/33 welding wire can weld. CT15C heat-resistant castings (UNS N08151) and similar centrifugal-cast or mould-cast components per DIN 17465 are also compatible.
Why does 21/33 contain Niobium (Nb)?
The ~1.2% Nb forms stable NbC carbides that maintain creep strength and stress-rupture resistance at temperatures up to 1050°C. Without Nb stabilisation, weld deposits lose strength through carbide coarsening during extended high-temperature service.
Is 21/33 fully austenitic? Does it require a special welding technique?
Yes. 21/33 deposits are fully austenitic with zero ferrite. Use stringer beads only (no weaving), maintain convex bead profiles, keep heat input low, fill all craters, hold interpass temperature under 175°C (350°F), and avoid highly restrained joint designs to prevent solidification cracking.
What is the Thermanit Equivalent of 21/33 Wire?
The Thermanit equivalent of 21/33 wire is Thermanit 21/33 SO
Can 21/33 welds be heat-treated?
The weld metal is normally used in the as-welded condition. An optional stabilisation anneal at 870°C (1600°F) for 3 hours, followed by air cooling, can be applied to optimise creep properties for long-duration service.