Seamless Hastelloy C22 Pipe
Compared to Alloy C276, Hastelloy C22 provides enhanced protection against oxidizing aqueous media, including wet chlorine and solutions containing nitric acid or oxidizing acids with chlorine ions. Our C22 seamless pipes are indispensable for pollution control, flue gas desulfurization (FGD), and pharmaceutical chemical processing. Through advanced cold-drawing and vacuum annealing, GZH ensures every pipe maintains tight dimensional tolerances and a high-integrity surface finish, delivering maximum durability for the most aggressive industrial environments.
Seamless Hastelloy C22 Pipe (UNS N06022 / Alloy C22)
SeamlessHastelloy C22 pipes, also known as Alloy C22 pipes or UNS N06022 pipes, are premium corrosion-resistant piping materials manufactured from a nickel-chromium-molybdenum-tungsten superalloy. These pipes are widely used in industries requiring outstanding resistance to aggressive chemical environments.
Produced according to ASTM B622 / ASME SB622 standards, seamless Hastelloy C22 tubing offers superior mechanical strength, excellent weldability, and exceptional resistance to both oxidizing and reducing media.
Because of its versatile corrosion resistance, Alloy C22 is considered one of the most advanced materials in the Hastelloy alloy family.
What is Hastelloy C22 (UNS N06022)?
Hastelloy C22 is a Ni-Cr-Mo-W alloy specifically designed to provide exceptional resistance to severe corrosive environments.
Compared with other nickel alloys, Alloy C22 demonstrates superior resistance to:
- Pitting corrosion
- Crevice corrosion
- Stress corrosion cracking (SCC)
- Intergranular corrosion
The alloy is especially resistant to environments containing chlorides, oxidizing acids, and mixed chemical solutions.
This makes UNS N06022 seamless pipes an ideal solution for highly demanding industrial applications.
Key Advantages of Seamless Hastelloy C22 Pipes
Outstanding Corrosion Resistance
Hastelloy C22 pipes perform exceptionally well in aggressive chemicals such as:
- Wet chlorine
- Ferric chloride
- Cupric chloride
- Formic acid
- Acetic acid
- Chloride-containing brine solutions
Seamless Structural Integrity
Unlike welded pipes, seamless Hastelloy C22 pipes are manufactured from a solid billet, ensuring:
- No weld seam defects
- Higher pressure resistance
- Uniform metallurgical structure
Excellent High Temperature Performance
Hastelloy C22 maintains excellent mechanical and corrosion resistance properties from cryogenic temperatures up to 816°C (1500°F).
Superior Fabrication and Weldability
The alloy’s low carbon content reduces carbide precipitation during welding, preserving corrosion resistance in the heat-affected zone (HAZ).
Comprehensive Guide to Seamless Hastelloy C22 (UNS N06022) Pipes
What is a Seamless Hastelloy C22 Pipe?
Seamless Hastelloy C22 pipes (also known as Alloy C22orUNS N06022) are premium, high-performance piping solutions engineered from a solid nickel-chromium-molybdenum-tungsten superalloy. Unlike welded alternatives, the seamless construction is achieved by extruding a solid billet, eliminating the risk of weld-related failures.
As the most versatile member of the Hastelloy family, Grade C22 offers exceptional resistance to a broad spectrum of aggressive chemical environments, including both oxidizing and reducing acids. Its unique chemical balance provides superior protection against localized corrosion, such as pitting,crevice corrosion, and stress corrosion cracking (SCC).
Key Technical Advantages
- Exceptional Corrosion Resistance: Highly effective against wet chlorine, formic/acetic acids, ferric/cupric chlorides, and brine.
- Structural Integrity: The seamless manufacturing process ensures uniform grain structure and higher pressure-bearing capacity.
- High-Temperature Stability: Maintains robust mechanical properties and oxidation resistance from cryogenic temperatures up to 1500°F (816°C).
- Optimized Weldability: Low carbon content minimizes carbide precipitation during secondary fabrication, preserving corrosion resistance in heat-affected zones (HAZ).
Product Specifications and Data
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for Hastelloy C22.
Table 1: Chemical Composition of Hastelloy C22
The composition of Hastelloy C22 is carefully balanced to achieve its superior corrosion resistance and high strength.
| Ni | Cr | Mo | W | C | Si | Co | Mn | V | P | S |
| Bal | 20.00-22.50 | 12.50-14.50 | 2.50-3.50 | ≤0.015 | ≤0.080 | ≤2.50 | ≤0.50 | ≤0.35 | ≤0.02 | ≤0.02 |
Table 2: Typical Mechanical Properties of Hastelloy C22
Hastelloy C22 is specifically designed to maintain its strength and shape in high-stress, corrosive environments.
Tensile Strength | Yield Strength | Elongation | Hardness |
≥ 690 MPa | ≥ 310 MPa | ≥ 45% | ≤ 100 HRB |
Table 3: Typical Physical Properties of Hastelloy C22
These physical properties highlight the material's ability to perform reliably under a wide range of conditions.
Density | Melting Point | Thermal Expansion | Thermal Conductivity | Modulus of Elasticity | Electrical Resistivity |
8.69 g/cm³ | 1357-1399 ℃ | 12.4 µm/m·℃ | 10.1 W/m·K | 206 GPa | 1.14 µΩ·m |
Applications of Hastelloy C22 Pipes
Because of its exceptional corrosion resistance, Hastelloy C22 seamless pipes are widely used in the following industries.
Chemical Processing Industry
Used for reactors, heat exchangers, and acid-handling pipelines.
Flue Gas Desulfurization (FGD)
Ideal for scrubbers and flue gas systems exposed to corrosive gases.
Pharmaceutical Industry
Used in high-purity piping systems resistant to cleaning chemicals and organic catalysts.
Pulp and Paper Industry
Applied in chlorine dioxide processing equipment and bleaching plants.
Manufacturing Process of ASTM B622 Hastelloy C22 Pipes
The production process includes several critical steps:
- Billet Heating – Controlled heating ensures proper metal plasticity.
- Hot Extrusion – Forms seamless hollow tubes with dense grain structure.
- Cold Drawing – Achieves precise OD and wall thickness tolerances.
- Solution Annealing – Restores corrosion resistance through heat treatment.
- Finishing & Inspection – Straightening, cutting, and surface finishing.
Quality Inspection and Testing
To ensure international compliance, each pipe undergoes strict testing procedures.
Material Certification
MTC according to EN 10204 3.1 / 3.2.
Chemical Testing
100%Positive Material Identification (PMI).
Mechanical Testing
- Tensile testing
- Hardness testing
- Flattening tests
- Flaring tests
Non-Destructive Testing
- Eddy Current Testing (ET)
- Ultrasonic Testing (UT)
Frequently Asked Questions (FAQ)
What is the difference between Hastelloy C22 and C276?
Both are nickel-based corrosion resistant alloys, but Hastelloy C22 offers better resistance to oxidizing environments and improved protection against pitting and crevice corrosion.
What standard covers Hastelloy C22 seamless pipes?
The most common manufacturing standard is ASTM B622 / ASME SB622.
What industries use Hastelloy C22 pipes?
Typical industries include:
- Chemical processing
- Pollution control
- Pharmaceuticals
- Pulp and paper
- Petrochemical processing
Is Hastelloy C22 better than stainless steel?
Yes. Hastelloy C22 provides significantly higher corrosion resistance than conventional stainless steels such as 316L, especially in chloride-containing environments.
