High-Performance Nickel Alloy Pipes for Your Industrial Requirements
HC-276, commonly referred to as Hastelloy C-276, is a nickel-based superalloy celebrated for its exceptional corrosion resistance and robust performance across extreme environments. Below is a structured and detailed overview:
HC-276 is part of the Hastelloy family, a group of nickel-molybdenum-chromium alloys engineered to withstand aggressive chemical, high-temperature, and high-pressure conditions. Its unique composition and microstructure make it a preferred material in industries where corrosion resistance and mechanical stability are critical.
| Ni | Cr | Fe | Co | Mo | W | P |
| Remainder | 14.0-16.5 | 4.0-7.0 | 2.5max | 15.0-17.0 | 3.0-4.5 | 0.04max |
| Si | Mn | C | c | S | | |
| 0.08max | 1.0max | 0.01max | 0.35max | 0.03max | | |
HC-276’s standout feature is its resistance to a broad range of corrosive environments:
- Acids: Withstands strong reducing acids (e.g., sulfuric, hydrochloric, hydrofluoric) and mixed acids (e.g., sulfuric-hydrochloric blends), even at high concentrations and temperatures. For example, in 20% boiling hydrochloric acid, its annual corrosion rate is ≤0.1 mm/year, far outperforming 316L stainless steel.
- Chlorides: Resists pitting and crevice corrosion in chloride-rich solutions (e.g., seawater, brines) due to a high Pitting Resistance Equivalent Number (PREN ≈ 76).
- Alkalis: Performs well in concentrated alkaline solutions (e.g., sodium hydroxide) at moderate temperatures.
- Oxidizing Environments: Chromium content ensures stability in oxidizing media (e.g., nitric acid, hypochlorites) and high-temperature oxidation.
- Stress Corrosion Cracking (SCC): Shows minimal susceptibility to SCC in chloride or sulfide environments, a critical advantage over many stainless steels.
HC-276 can be fabricated using standard metalworking techniques, though its high strength requires careful handling:
- Forming: Cold working (e.g., bending, rolling) is feasible but may require intermediate annealing to restore ductility. Hot working is performed at 1,040–1,175°C (1,900–2,150°F).
- Welding: Can be welded using processes like TIG (GTAW) or MIG (GMAW) with matching filler metals (e.g., ERNiCrMo-4). Post-weld annealing is not required due to low carbon content, simplifying processing.
- Machining: Machinability is moderate; tools with high-speed steel or carbide inserts are recommended, with coolants to prevent overheating.
Due to its versatile performance, HC-276 is widely used in industries requiring corrosion and heat resistance:
- Chemical Processing: Reaction vessels, heat exchangers, and pipelines handling acids, solvents, and reactive chemicals.
- Oil & Gas: Downhole equipment, subsea pipelines, and offshore platforms exposed to brines, sulfides, and high pressures.
- Environmental Engineering: Flue gas desulfurization systems (FGD) and wastewater treatment equipment.
- Pharmaceuticals: Cleanroom components and reactor systems requiring high purity and resistance to sanitizing agents.
- Aerospace & Energy: Components in gas turbines and industrial furnaces operating at elevated temperatures.
HC-276 is governed by international standards, including:
- ASTM B575 (sheet, plate, strip)
- ASTM B574 (bars, rods, forgings)
- ASME Section VIII (pressure vessel code)
- ISO 15156 (for oilfield equipment in sour service).
