180 Degree Return Bend ASTM B366 N06022 Hastelloy C-22 For Heat Exchanger
A 180 Degree Return Bend made of ASTM B366 N06022 Hastelloy C-22 is a pipe fitting used in piping systems to change the direction of flow by 180 degrees. The return bend is essentially a U-shaped component that causes the fluid to reverse its direction. This type of bend is often used for reversing the direction of piping in a compact area without using multiple fittings and straight pipes.
Here’s a detailed breakdown:
1. Chemical Composition of ASTM B366 N06022 (Hastelloy C-22) (Weight %)
| Element | Min (%) | Max (%) |
| Nickel (Ni) | Balance | – |
| Chromium (Cr) | 20.0 | 22.5 |
| Molybdenum (Mo) | 12.5 | 14.5 |
| Iron (Fe) | 2.0 | 6.0 |
| Tungsten (W) | 2.5 | 3.5 |
| Cobalt (Co) | – | 2.5 |
| Manganese (Mn) | – | 0.5 |
| Vanadium (V) | – | 0.35 |
| Silicon (Si) | – | 0.08 |
| Carbon (C) | – | 0.015 |
| Phosphorus (P) | – | 0.02 |
| Sulfur (S) | – | 0.02 |
Notes:
- Residual elements (Cu, Al, Ti, etc.) are typically limited to trace amounts.
- The composition ensures superior corrosion resistance in oxidizing and reducing environments.
2. Mechanical Properties of ASTM B366 N06022 (Hastelloy C-22)
| Property | Typical Value | ASTM B366 Requirement |
| Tensile Strength (MPa) | ≥ 690 | 690 min |
| Yield Strength (0.2% Offset, MPa) | ≥ 310 | 310 min |
| Elongation (% in 50 mm) | ≥ 45 | 45 min |
| Hardness (Rockwell B) | ≤ 100 HRB | Typically 90-100 HRB |
Additional Notes:
- Heat Treatment: Solution annealed at 2050°F (1121°C) followed by rapid cooling for optimal corrosion resistance.
- Impact Toughness: Excellent (Charpy V-notch values typically > 100 J at room temperature).
- Density: ~8.69 g/cm³
- Melting Range: ~1350-1390°C (2462-2534°F)
Key Takeaways
✔ Corrosion Resistance: Excellent in chlorides, sulfuric acid, nitric acid, and seawater.
✔ High Strength: Maintains mechanical properties at elevated temperatures.
✔ Weldability: Good, but requires proper filler metals (e.g., ERNiCrMo-10).
3. 180-Degree Return Bend
- A U-shaped pipe fitting that allows flow to double back.
- Commonly used in heat exchangers, pipelines, and process systems.
4. ASTM B366 Specification
- Covers wrought nickel-alloy fittings (butt-welding, socket-welding, threaded).
- Includes requirements for chemical composition, mechanical properties, dimensions, and testing.
5. Manufacturing & Types
- Seamless or Welded: Can be fabricated via extrusion or bending from pipe.
- Butt-Weld Ends: Typically used for high-pressure/temperature systems.
- Dimensions: Follow ASME B16.9 (for factory-made bends) or custom specifications.
6. Key Features of ASTM B366 N06022 180 Degree Return Bend
- High-Temperature Strength: Retains properties in extreme conditions.
- Weldability: Compatible with common welding techniques (TIG, MIG).
- Surface Finish: Often supplied with a smooth finish to minimize contamination.
- Superior Corrosion Resistance: Outperforms stainless steel (316L) and even Hastelloy C-276 in mixed acid environments.
Primary Applications of Hastelloy C-22 180° Return Bend
1. Chemical Processing Industry
- Acid & Chloride Environments: Used in reactors, heat exchangers, and piping systems handling:
- Sulfuric acid, hydrochloric acid, phosphoric acid.
- Chlorine, bleach, and other aggressive chemicals.
- Pollution Control: Scrubbers, waste gas treatment, and effluent systems.
2. Oil & Gas (Including Offshore & Subsea)
- Downhole & Wellhead Components: Resists sour gas (H₂S), CO₂, and brine corrosion.
- Refinery Piping: Used in crude oil distillation, hydroprocessing, and sulfur recovery units.
3. Power Generation
- Flue Gas Desulfurization (FGD) Systems: Handles sulfuric acid condensates and chlorides in scrubbers.
- Nuclear Waste Processing: Resists radiation-induced corrosion and acidic nuclear byproducts.
4. Pharmaceutical & Food Processing
- High-Purity Systems: Used in CIP (Clean-in-Place) systems due to non-contaminating properties.
- Sterile Processing: Resists pitting from chlorinated sanitizers (e.g., hypochlorite).
5. Marine & Offshore
- Seawater Cooling Systems: Resists crevice corrosion and biofouling in heat exchangers.
- Desalination Plants: Used in brine heaters and evaporator tubing.
6. Pulp & Paper Industry
- Bleach Plants: Withstands chlorine dioxide and other harsh bleaching agents.
