Alloy C2000
Alloy C2000 (UNS N06200) is a nickel-chromium-molybdenum-copper alloy built to resist both oxidising and reducing corrosive media. Its balanced chemistry, with high molybdenum and copper additions, makes it one of the most broadly corrosion-resistant nickel alloys for aggressive chemical process environments.
1. Chemical Composition
The table below shows the elemental composition of Alloy C2000. The copper and molybdenum contents are what separate it from conventional Ni-Cr-Mo alloys.
| Grade | C | Mn | Si | S | Cr | Mo | Fe | W | Co | Other |
| N06200 (C-2000) | ≤ 0.01 | ≤ 0.50 | ≤ 0.08 | ≤ 0.010 | 22.0–24.0 | 15.0–17.0 | 3.0 | — | 2.0 | Cu 1.3–1.9 |
2. Mechanical Properties
The table below lists the guaranteed minimum mechanical properties of Alloy C2000 in the solution-annealed condition.
| Grade (UNS) | Alloy Family | Tensile Min, ksi (MPa) | Yield Min, ksi (MPa) | Elong. Min, % | Fiber Stress, psi |
| N06200 | Low C Ni-Cr-Mo-Cu (C-2000) | ≥ 100 (690) | ≥ 41 (283) | ≥ 45 % | 25,000 |
3. Equivalent Grade
The table below maps Alloy C2000 to its equivalent designations across major international standards.
| GRADE | UNS | GB | JIS | ISO | DIN/EN | GOST | |
| ISC | NEW | ||||||
| Alloy C2000 | N06200 | — | — | — | — | 2.4675 | — |
4. Key Technical Advantages
- Passive Layer Stability: The 18% Cr content forms a stable chromium oxide passive layer that resists oxidizing acids, atmospheric corrosion, and mild aqueous environments.
- Weldability: Grade 304 can be welded by all standard fusion methods without post-weld heat treatment in most applications. However, inter-granular sensitization risk exists in heavy-section welds.
- Formability: Good cold-working characteristics make it suitable for deep-drawn components, rolled tube forms, and complex fabricated assemblies.
- Low-Temperature Toughness: Retains austenitic structure and impact toughness at sub-zero temperatures, with no ductile-to-brittle transition behavior typical of ferritic steels.
- Dual-Environment Corrosion Resistance: The combination of 16% Mo and 1.6% Cu allows Alloy C2000 to resist both strongly oxidising acids (e.g., nitric acid) and reducing acids (e.g., hydrochloric and sulfuric acid). Few single alloy systems can handle both types of environment.
- Strong Resistance to Localised Attack: Alloy C2000 has excellent pitting and crevice corrosion resistance in chloride-bearing environments, outperforming many conventional Ni-Cr-Mo grades in ASTM G48 tests.
- Low Carbon for Sensitisation Control: The 0.010% carbon ceiling eliminates the risk of chromium carbide precipitation at grain boundaries during welding. This preserves intergranular corrosion resistance without requiring post-weld heat treatment.
- Technical Note: Alloy C2000 is specifically designed as a better alternative to Hastelloy C-276 and C-22 in applications requiring resistance to wet chlorine, chlorine dioxide, and hypochlorite bleach solutions.
5. Common Manufacturing Standards
ASTM B622: Standard Specification for Seamless Nickel and Nickel-Cobalt Alloy Pipe and Tube. Covers Alloy C2000 in solution-annealed seamless tubular form.
JIS Standards:
- JIS H 4552: Nickel and nickel alloy seamless pipes and tubes (note: C2000 / N06200 may not be explicitly listed; verify applicability against current JIS revision)
Standards Comparison Table:
| ASTM | EN/DIN | JIS | GB/T | GOST |
| ASTM B622 | EN 10216-5 | JIS H 4552 (unconfirmed) | - | - |
6. Primary Applications
- Chlorine and Bleach Production: C2000 handles wet chlorine gas, chlorine dioxide, and sodium hypochlorite in pulp and paper bleaching circuits. This industry is alternately exposed to both oxidising and reducing conditions.
- Pharmaceutical Manufacturing: Process piping and reactor tubing in aggressive solvent and acid environments that require ultra-low contamination and consistent corrosion performance.
- Sulfuric Acid Processing: Heat exchangers and piping in concentrated H2SO4 service at elevated temperatures where reducing conditions dominate.
- Flue Gas Desulfurization (FGD): Absorber headers and spray nozzle tubing exposed to acidic scrubbing liquors containing chloride and sulfate ions.
- Hydrometallurgical Leaching: Pressure leach circuits in nickel and copper refining where hydrochloric and sulfuric acid concentrations fluctuate under high temperature and pressure.