UNS N06022|2.4602|Hastelloy C22 Seamless 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, XinZhe ensures every pipe maintains tight dimensional tolerances and a high-integrity surface finish, delivering maximum durability for the most aggressive industrial environments.
What Is a Seamless Hastelloy C22 Pipe?
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.
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:
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 Features and Technical Advantages
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.
- 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.
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).
- 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).
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for Hastelloy C22.
Product Specifications and Data
The composition of Hastelloy C22 is carefully balanced to achieve its superior corrosion resistance and high strength.
Hastelloy C22 is specifically designed to maintain its strength and shape in high-stress, corrosive environments.
These physical properties highlight the material's ability to perform reliably under a wide range of conditions.
Chemical Composition
Chemical Composition
| 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 |
Typical Mechanical Properties
Typical Mechanical Properties
| Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|
| ≥ 690 MPa | ≥ 310 MPa | ≥ 45% | ≤ 100 HRB |
Typical Physical Properties
Typical Physical Properties
| 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 |
Dimensional Standards and Tolerances
Seamless Hastelloy C22 pipes are produced to international standards, ensuring high precision and engineering compatibility:
- Standards Covered: ASTM B622 / ASME SB622 – Seamless Nickel and Nickel-Cobalt Alloy Pipe and Tube.
- Typical Tolerances: OD tolerance ±0.2 mm to ±0.5%; wall thickness ±10% to ±12.5%; length per standard or customer requirement.
- Available Sizes: OD 6 mm to 219 mm, wall thickness 1 mm to 20 mm (custom sizes on request).
Common Industrial Applications
Because of its exceptional corrosion resistance, Hastelloy C22 seamless pipes are widely used in the following industries.
Chemical Processing Industry
- Reactors and heat exchangers
- Acid-handling pipelines
- Equipment exposed to mixed and oxidising acids
Flue Gas Desulfurization (FGD)
- Scrubbers and absorber internals
- Flue gas systems exposed to corrosive gases
Pharmaceutical Industry
- High-purity piping systems resistant to cleaning chemicals
- Organic catalyst handling lines
Pulp and Paper Industry
- Chlorine dioxide processing equipment
- Bleaching plant piping and vessels
Quality Assurance and Manufacturing Process
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.
To ensure international compliance, each pipe undergoes strict testing procedures.
MTC according to EN 10204 3.1 / 3.2.
100%Positive Material Identification (PMI).
Every Hastelloy C22 (UNS N06022) seamless pipe undergoes strict quality control from billet selection through forming, heat treatment and final inspection:
Certification
- EN 10204 3.1 / 3.2 Material Test Certificates (MTC) issued for every heat
- Compliance with ASTM B622 / ASME SB622 and ASTM B619 / ASME SB619
- Full heat traceability from raw material to finished pipe
Non-Destructive Testing (NDT)
- Ultrasonic Testing (UT) per ASTM E213
- Eddy Current Testing (ET) for surface and near-surface defects
- Hydrostatic pressure testing to verify pipe integrity
Material Verification
- 100% Positive Material Identification (PMI)
- Chemical analysis confirming composition against the specified grade
- Carbon and sulfur analysis where required
Mechanical Testing
- Tensile, yield and elongation testing per ASTM A370
- Hardness testing to confirm the specified condition
- Flattening, flaring and intergranular corrosion tests
Dimensional Inspection
- OD, wall thickness and ovality verified against the tolerance table
- Length, straightness and end preparation checked before dispatch
- Third-party inspection available through ABS, DNV, BV, TUV or SGS
Hastelloy C22 vs Hastelloy C276 – Technical Comparison
Both Alloy C22 (UNS N06022) and Alloy C276 (UNS N10276) belong to the Ni-Cr-Mo family of corrosion-resistant superalloys. C22 was developed as an improved version of C276 with better resistance to oxidizing media and improved thermal stability.
Chemical and Metallurgical Differences
- Chromium content: C22 contains 20.0–22.5% Cr versus 14.5–16.5% in C276, giving C22 superior resistance to oxidizing acids such as nitric acid and wet chlorine.
- Tungsten content: C22 contains 2.5–3.5% W versus 3.0–4.5% W in C276, balanced for optimum pitting resistance.
- Molybdenum: 12.5–14.5% in C22 versus 15.0–17.0% in C276.
- Iron content: Both alloys are limited to 2.0–6.0% Fe to preserve corrosion performance.
- Oxidizing environments: C22 outperforms C276 in oxidizing chlorides, ferric chloride and cupric chloride solutions.
- Reducing environments: Both alloys perform equivalently in hydrochloric and sulfuric acid.
- Pitting and crevice corrosion: C22 offers a higher Pitting Resistance Equivalent Number (PREN) in oxidizing conditions.
- Thermal stability: C22 resists grain-boundary precipitation better in the 650–1040°C range, reducing the risk of sensitization during welding.
Selection Guide
- ChooseHastelloy C22 for mixed acid streams, wet chlorine, hypochlorite and oxidizing chloride service.
- ChooseHastelloy C276 for highly reducing environments and where long-term field experience with C276 already exists.
- Both grades are available as seamless pipe to ASTM B622 / ASME SB622.
Ordering Information
- Specify grade (UNS N06022), manufacturing standard and edition (ASTM B622 / ASME SB622).
- Provide outside diameter × wall thickness, length, quantity and end finish.
- State required testing, documentation level (EN 10204 3.1 / 3.2) and any third-party inspection requirements.
Frequently Asked Questions
What is Hastelloy C22 seamless pipe?
Hastelloy C22 (UNS N06022) is a nickel-chromium-molybdenum-tungsten alloy seamless pipe containing 20.0–22.5% Cr, 12.5–14.5% Mo and 2.50–3.50% W. Its high chromium content gives it outstanding resistance to both oxidising and reducing media, including wet chlorine and chlorine dioxide.
What is the difference between Hastelloy C22 and C276?
C22 contains 20.0–22.5% chromium against 14.5–16.5% for C276, which makes C22 substantially better in oxidising acids, wet chlorine and hypochlorite environments. C276 has higher molybdenum (15.0–17.0%) and performs slightly better in strongly reducing hydrochloric acid. C22 also has better resistance to chloride stress corrosion cracking.
Which standards cover Hastelloy C22 seamless pipe?
Hastelloy C22 seamless pipe is manufactured to ASTM B622 / ASME SB622 and ASTM B619 / ASME SB619, with ASTM B829 covering general requirements. EN 10204 3.1 / 3.2 material certificates are issued with every heat.
What is Hastelloy C22 pipe used for?
Typical applications include reactors, heat exchangers and acid-handling pipelines in chemical processing, scrubbers and absorber internals in flue gas desulfurization systems, high-purity pharmaceutical piping, and chlorine dioxide processing equipment and bleaching plants in the pulp and paper industry.
Ready to Request a Quotation?
Send your Seamless Hastelloy C22 Pipe enquiry with grade, applicable ASTM/ASME standard and edition, OD × wall thickness, length, quantity, end finish, delivery destination and inspection documents — you will get a written quotation stating the specification and edition, delivery condition, documents included and lead time.
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