Hastelloy C276 Welding and Fabrication Guide
Hastelloy C276 (UNS N10276) is a nickel-molybdenum-chromium alloy with excellent corrosion resistance, especially in aggressive chemical environments. It is widely used in industries such as chemical processing, pollution control, marine, and pulp & paper. Proper welding and fabrication techniques are essential to maintain its corrosion-resistant properties.
🔧 Welding of Hastelloy C276
1. Weldability
Hastelloy C276 has good weldability using conventional methods.
It is resistant to weld decay (intergranular corrosion) even in the welded condition.
Welded joints retain corrosion resistance without post-weld heat treatment.
2. Recommended Welding Methods
| Process | Notes |
|---|---|
| GTAW (TIG) | Most common; offers clean, precise welds. |
| GMAW (MIG) | Suitable for thicker sections; good deposition rates. |
| SMAW (Stick) | Used for fieldwork or thick plate welding. |
| PAW (Plasma Arc) | For very fine, controlled welding (less common). |
3. Filler Metals
Use matching filler metal: ERNiCrMo-4 (for GTAW/MIG) or ENiCrMo-4 (for SMAW).
Avoid mismatched fillers to maintain corrosion resistance.
4. Preparation
Clean the base metal thoroughly (no oil, grease, or oxide).
Use dedicated tools for Hastelloy to avoid contamination from carbon steel or stainless steel.
5. Welding Tips
Keep interpass temperature below 150°C (300°F).
Use argon or argon/helium shielding gases for TIG/MIG welding.
Ensure adequate shielding of the root and back sides.
Avoid excessive heat input to prevent grain growth.
🛠️ Fabrication of Hastelloy C276
1. Machinability
Hastelloy C276 is tough and work-hardening, so use slow speeds and heavy feeds.
Use rigid tooling and coolant to extend tool life.
Carbide tools are preferred over HSS.
2. Cutting & Forming
Can be cut using plasma, waterjet, or laser cutting.
Cold forming is possible but requires higher force than for stainless steels.
Anneal after severe cold work to restore ductility.
3. Heat Treatment
Supplied in solution-annealed condition (2050°F / 1120°C) and rapidly quenched.
No post-fabrication heat treatment required unless severely cold-worked.
🧪 Post-Fabrication Considerations
Pickling and Passivation may be used to remove surface oxides.
Avoid contamination from tools and materials that may compromise corrosion resistance.
Inspect welds using non-destructive testing (NDT) methods if required.
✅ Summary
| Feature | Details |
|---|---|
| Weldability | Excellent, no PWHT required |
| Filler Metal | ERNiCrMo-4 / ENiCrMo-4 |
| Shielding Gas | Pure argon or argon/helium |
| Machinability | Difficult, needs proper tooling |
| Forming | Cold forming with care; anneal if needed |
| Cutting Methods | Laser, plasma, waterjet, mechanical |
| Heat Treatment | Annealed at 1120°C, rapid quench |
SSM offers Hastelloy C276 products including pipes, fittings, flanges, fasteners, bars, and plates, all manufactured with proper welding and fabrication quality to meet industrial standards.
Let me know if you'd like a welding procedure specification (WPS) example.
