What are characteristics of C2000 Hastelloy - Knowledge

1. What are the characteristics of Hastelloy C2000?

Hastelloy C2000 is a nickel-chromium-molybdenum (Ni-Cr-Mo) superalloy developed for extreme corrosion-resistant applications. It combines the advantages of traditional Hastelloy C-series alloys (e.g., C276, C22) while optimizing elemental composition to enhance performance in harsh environments. Its core characteristics are as follows:

1.1 Exceptional Corrosion Resistance

Broad-spectrum resistance: Excels in resisting both oxidizing and reducing acids, including sulfuric acid, hydrochloric acid, phosphoric acid, and acetic acid. It outperforms C276 in dilute sulfuric acid (10–40% concentration) and C22 in high-temperature hydrochloric acid.

Pitting and crevice corrosion resistance: The balanced addition of chromium (Cr: 23–27%) and molybdenum (Mo: 15–18%) forms a dense passive oxide film on the surface, reducing the risk of pitting (critical pitting temperature, CPT > 50°C in 6% FeCl₃ solution) and crevice corrosion.

Resistance to intergranular corrosion (IGC): Low carbon (C ≤ 0.015%) and silicon (Si ≤ 0.08%) content, combined with controlled titanium (Ti: 0.6–1.2%) addition, prevents carbide precipitation at grain boundaries during welding or heat treatment, eliminating IGC risks.

1.2 Excellent Mechanical Properties

Maintains high strength and toughness across a wide temperature range (-270°C to 427°C). It retains ductility even at cryogenic temperatures, making it suitable for low-temperature applications.

Good fatigue resistance, especially in corrosive environments (stress corrosion cracking resistance), which is critical for components under cyclic loads (e.g., valves, pumps).

1.3 Superior Weldability and Fabricability

Can be welded using common methods (TIG, MIG, SMAW) without pre-heating or post-weld heat treatment (PWHT), simplifying manufacturing processes.

Low thermal expansion coefficient (12.8 × 10⁻⁶/°C, 20–100°C) and good thermal conductivity, reducing thermal stress during welding and operation.

1.4 High-Temperature Stability

Resists oxidation and scaling in air up to 870°C, and maintains structural stability in high-temperature corrosive gases (e.g., flue gas, chemical process streams) without significant performance degradation.

2. What is the yield strength of Hastelloy C2000?

The yield strength of Hastelloy C2000 varies slightly depending on the product form (wrought, annealed, cold-worked) and testing temperature, as specified in international standards (e.g., ASTM B622, AMS 5878). The key data are as follows:

Product Form	Testing Temperature	Yield Strength (0.2% Offset)	Standard Reference
Annealed (Solution-treated)	Room Temperature (20–25°C)	Minimum: 276 MPa; Typical: 310 MPa	ASTM B622, AMS 5878
Annealed	100°C	Minimum: 265 MPa; Typical: 295 MPa	ASTM B622
Annealed	200°C	Minimum: 255 MPa; Typical: 280 MPa	ASTM B622
Annealed	300°C	Minimum: 240 MPa; Typical: 260 MPa	ASTM B622
Cold-worked (20% Cold Reduction)	Room Temperature	Minimum: 550 MPa; Typical: 580 MPa	Manufacturer Data (Haynes International)

Note: The "0.2% offset" yield strength is the industry standard for measuring this alloy, as it reflects the stress at which permanent deformation (0.2% of the specimen length) occurs. Cold working significantly increases yield strength by refining the grain structure, but may slightly reduce ductility.

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3. What is the tensile strength of Hastelloy C2000?

Similar to yield strength, the tensile strength of Hastelloy C2000 is influenced by product form, heat treatment state, and testing temperature. The following data are in line with mainstream international standards and manufacturer specifications:

Product Form	Testing Temperature	Tensile Strength	Standard Reference
Annealed (Solution-treated)	Room Temperature (20–25°C)	Minimum: 655 MPa; Typical: 700 MPa	ASTM B622, AMS 5878
Annealed	100°C	Minimum: 630 MPa; Typical: 670 MPa	ASTM B622
Annealed	200°C	Minimum: 600 MPa; Typical: 640 MPa	ASTM B622
Annealed	300°C	Minimum: 570 MPa; Typical: 605 MPa	ASTM B622
Annealed	400°C	Minimum: 540 MPa; Typical: 575 MPa	ASTM B622
Cold-worked (20% Cold Reduction)	Room Temperature	Minimum: 860 MPa; Typical: 900 MPa	Manufacturer Data (Haynes International)

Note: Tensile strength refers to the maximum stress the alloy can withstand before fracture. For annealed Hastelloy C2000, the tensile strength decreases gradually with increasing temperature, but remains sufficient for most high-temperature corrosion-resistant applications (up to 427°C).