Corrosion Resistant Hastelloy Alloy C-22 UNS N06022 W.Nr.2.4602 Welding Bolts for Chemical Processing and Marine Applications
Welding Hastelloy C-22 (UNS N06022, W.Nr. 2.4602) bolts requires expertise due to its high corrosion resistance and alloy composition. This nickel-based alloy, containing chromium, molybdenum, and tungsten, offers excellent resistance to pitting, crevice corrosion, and stress corrosion cracking. For welding, GTAW (TIG) is preferred, using matching filler metals like ERNiCrMo-10. Cleanliness is crucial to prevent contamination, and low heat input minimizes distortion and carbide precipitation. Preheating is unnecessary, and post-weld heat treatment is typically not required. Shielding gas, such as argon or argon-helium mixtures, ensures a stable arc and prevents oxidation. Proper technique results in durable, corrosion-resistant welds suitable for harsh chemical environments, making Hastelloy C-22 bolts reliable in demanding applications.
| Chemical Composition Wt.% | % | Ni | Cr | Fe | C | Mn | Si | Mo | V | P | S | Co | W |
| Min | Bal. | 20 | 2 |
| | | 12.5 | | | | | 2.5 |
| Max | Bal. | 22.5 | 6 | 0.015 | 0.5 | 0.08 | 14.5 | 0.35 | 0.02 | 0.02 | 2.5 | 3.5 |
| Physical Constants | Density(g/cm³) | 8.9 |
| Melting Range(℃) | 1325-1370 |
| Minimum mechanical properties of alloy at room temperature | Typical mechanical properties | Tensile strength Rm N/mm² | Yield strength RP 0.2 N/mm² | Elongation A5 % |
| Solution treatment | 690 | 283 | 40 |
| Category/Type | hex bolts |
| Head type | outer hexagonal |
| Thread tolerance | 6G |
| Material | Hastelloy Alloy C-22 |
| Performance level | 8.8 |
| Thread specification | M6~M100 |
| Head side length | 10-120(mm) |
| Head thickness | 6.6-60(mm) |
| Total length | 30~800(mm) |
Welding Hastelloy C-22 (UNS N06022, W.Nr. 2.4602) bolts requires careful consideration due to the material’s composition and properties. Here are the key features to keep in mind:
1. Corrosion Resistance
- Exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking.
- Withstands harsh environments, including oxidizing and reducing agents, making it ideal for chemical processing, marine, and aerospace applications.
2. Weldability
- Highly weldable using common techniques like GTAW (TIG), GMAW (MIG), and SMAW (stick welding).
- Low risk of carbide precipitation, reducing susceptibility to intergranular corrosion.
- Autogenous welding (fusion welding without filler) is possible but may not be ideal for thicker sections.
3. Recommended Filler Material
- Use ERNiCrMo-10 (AWS A5.14) filler wire for GTAW/MIG processes.
- For stick welding (SMAW), ENiCrMo-10 electrodes are recommended.
4. Preheat & Post-Weld Treatment
- No preheating required due to low carbon content.
- Post-weld heat treatment (PWHT) is typically not necessary, but stress-relief annealing at 1100–1150°C (2012–2102°F) may be performed for specific applications.
5. Welding Challenges & Precautions
- Maintain a low heat input to prevent grain growth and hot cracking.
- Use argon shielding gas (pure or Ar-He mix) to avoid oxidation.
- Avoid contamination from iron-based tools or grinding dust to prevent embrittlement.
Applications:
Welding Hastelloy C-22 (UNS N06022, W.Nr. 2.4602) bolts requires special attention due to its high nickel content and excellent corrosion resistance. Here’s what you need to know:
1. Material Characteristics
- Hastelloy C-22 is a nickel-chromium-molybdenum alloy with exceptional resistance to oxidizing and reducing environments.
- Used in harsh chemical processing, marine, and aerospace applications.
- Prone to hot cracking and segregation if not welded correctly.
2. Welding Process Selection
- GTAW (TIG) Welding – Preferred for precision and low heat input.
- GMAW (MIG) Welding – Used for larger weldments but requires pulsed spray transfer.
- SMAW (Stick) Welding – Possible but not commonly used for bolt applications.
- PAW (Plasma Arc Welding) – Effective for automated processes.
3. Filler Material Selection
- Use ERNiCrMo-10 (AWS A5.14) for the best compatibility.
- Alternative: ERNiCrMo-4, but it may have slightly different composition.
4. Pre-Weld Preparation
- Clean the surface thoroughly to remove oil, grease, or oxide layers.
- Use a carbide burr or mechanical cleaning (avoid iron-contaminated tools).
- Maintain sharp edge preparation to avoid porosity.
5. Welding Parameters
- Low heat input to prevent excessive grain growth.
- Interpass temperature: Maintain below 93°C (200°F).
- Use Argon or Argon-Helium shielding gas to prevent oxidation.
- Avoid weaving; use stringer beads instead.
6. Post-Weld Treatment
- Solution annealing at 2050°F (1121°C) and rapid quenching may be needed for optimal corrosion resistance.
- Pickling and passivation with nitric acid to restore corrosion resistance.
7. Application Considerations
- Used in chemical plants, desalination, and high-temperature oxidizing environments.
- Bolt welding should be done with minimal distortion to maintain mechanical properties.
- If possible, consider using mechanical fastening over welding for better reliability.
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Corrosion Resistant Hastelloy Alloy C-22 UNS N06022 W.Nr.2.4602 Welding Bolts for Chemical Processing and Marine Applications Images
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