Hastelloy C22 Seamless Tube

UNS N06022 | 2.4602 | ASTM B622

Hastelloy C22 Seamless Tube (N06022 / 2.4602) is manufactured to ASTM B622 from tube billet, cold-drawn to the required outside diameter and wall thickness. Supplied from our Wenzhou mill with EN 10204 3.1 mill test certificate, PMI and dimensional inspection on request.

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What Is a Seamless Hastelloy C22 Tube?

Hastelloy C22 (UNS N06022 / W.Nr. 2.4602) is a nickel-chromium-molybdenum alloy with tungsten, engineered to resist both oxidising and reducing media. Its higher chromium content than C276 improves resistance to oxidising acids and to pitting in halide-containing environments, while the tungsten addition strengthens resistance to localised corrosion, making C22 a preferred choice where C276 is borderline.

SeamlessHastelloy C22 tube (UNS N06022 / W.Nr. 2.4602) is a high-performance nickel–chromium–molybdenum–tungsten alloy, engineered to deliver exceptional corrosion resistance in both oxidizing and reducing environments.

Produced from solid billets through hot piercing and cold finishing, seamless C22 tubes feature a uniform, weld-free microstructure, ensuring superior mechanical strength, pressure resistance, and long-term reliability in critical applications.

Recognized as one of the most versatile corrosion-resistant nickel alloys, Hastelloy C22 is widely used in complex chemical processes where media conditions vary or are highly aggressive.

Hastelloy C22 Key Features and Technical Advantages

Feature	Description
Outstanding Universal Corrosion Resistance	Hastelloy C22 resists both oxidising and reducing media, giving it the broadest corrosion envelope of the C-family alloys.
Superior Resistance to Oxidising Acids	A higher chromium content than C276 improves performance in oxidising acids and in media containing ferric or cupric ions.
Excellent Localised Corrosion Resistance	Tungsten and molybdenum combine to resist pitting and crevice corrosion in halide-containing environments.
Resistance to Process Streams with Mixed Chemistry	C22 tolerates chlorides, hypochlorite and oxidising contaminants simultaneously, which makes it the default upgrade where C276 is marginal.
Good Fabricability and Weldability	The alloy is readily formed and welded and retains corrosion resistance in the as-welded condition.

Hastelloy C22 Product Specifications and Data

The addition of Tungsten (W) specifically enhances its resistance to pitting in halide-containing environments.

Table 1: Chemical Composition (UNS N06022)

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

Hastelloy C22 is specifically designed to maintain its strength and shape in high-stress, corrosive environments.

Table 2: Typical Mechanical Properties (Annealed)

Tensile Strength	Yield Strength	Elongation	Hardness
≥ 690 MPa	≥ 310 MPa	≥ 45%	≤ 100 HRB

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	1399 °C approx.	12.4 µm/m·°C (20-100°C)	11.1 W/m·K (20°C)	205 GPa	1.15 x 10⁻⁶ Ω·m (20°C)

Hastelloy C22 Dimensional Standards and Tolerances

Hastelloy C22 seamless tubes are supplied to the dimensional tolerances of ASTM B622 / B829 unless a tighter project specification applies.

Hastelloy C22 Common Industrial Applications

Industry	Typical Applications
Chemical Processing	Reactors, heat exchangers and vessels Halide-containing process streams Mixed oxidising/reducing acid service
Pharmaceutical and Fine Chemicals	Reactor vessels and internals Purification equipment Corrosive media transfer
Pollution Control and Waste Treatment	Flue-gas desulphurisation scrubbers Waste-incineration equipment Effluent treatment systems
Pulp and Paper Industry	Bleach plant equipment Digester and liquor lines Heat exchangers
Offshore and Marine Engineering	Seawater and brine systems Offshore process pipework Cooling equipment

Hastelloy C22 Quality Assurance and Production Process

Process Step	Description
Certification	All Hastelloy C22 tubes are supplied to ASTM B622 / ASME SB622 and ASTM B619 / ASME SB619 with EN 10204 3.1 mill test certificates. Third-party inspection (SGS, BV, TUV, Lloyd's), PMI reports and full heat-number traceability can be provided on request.
Non-Destructive Testing (NDT)	Hydrostatic or eddy-current testing is performed on 100% of tubes. Ultrasonic testing (UT) and dye-penetrant inspection (PT) are available for critical service, with records retained for each production lot.
Material Verification	Positive Material Identification (PMI) and spectrometric analysis confirm that the chemical composition matches the ordered grade. Intergranular corrosion (IGC) testing to ASTM A262 Practice E is available for austenitic and nickel-alloy tubes.
Mechanical Testing	Tensile, yield, elongation and hardness tests are carried out per heat. Flattening, flaring and reverse-bend tests verify ductility, while creep-rupture data can be supplied for high-temperature grades.
Dimensional Inspection	Outside diameter, wall thickness, ovality and straightness are measured against ASTM A1016 / A1016M or EN 10216-5 tolerances. Length, square-cut ends and end-finish conditions are verified before packing.

Hastelloy C22 vs C276 / B3 – Technical Comparison

Hastelloy C22 was developed to widen the corrosion envelope of C276, particularly toward oxidising media, while keeping the reducing-acid capability that makes the family useful.

Chemistry

C22: approximately 22% Cr, 13% Mo, 3% W — higher chromium than C276
C276: approximately 15.5% Cr, 16% Mo, 4% W — higher molybdenum than C22
B3: nickel-molybdenum with controlled iron and chromium, for reducing acids only

Oxidising versus Reducing Performance

The extra chromium in C22 improves resistance to oxidising acids and to media containing ferric or cupric ions, while the tungsten and molybdenum retain the reducing-acid performance. C276 remains marginally better in the most aggressive reducing conditions.

Localised Corrosion

Both alloys resist pitting and crevice corrosion in chloride-bearing environments. C22 is usually preferred where the process stream contains both chlorides and oxidising contaminants, since it handles the combination with more margin.

Selection Guide

Choose Hastelloy C22 where the process combines chlorides with oxidising species, or where oxidising acids dominate
ChooseHastelloy C276 for the most aggressive reducing conditions and the broadest established service record
ChooseHastelloy B3 only for pure reducing-acid service without oxidising contaminants

Frequently Asked Questions About Hastelloy C22 Seamless Tubes

What is a Hastelloy C22 seamless tube?

Hastelloy C22 (UNS N06022 / W.Nr. 2.4602) is a nickel-chromium-molybdenum alloy tube with tungsten, produced without a longitudinal weld. It is engineered to resist both oxidising and reducing media, with a higher chromium content than C276.

What is the difference between Hastelloy C22 and C276?

C22 carries approximately 22% chromium against roughly 15.5% in C276, which improves performance in oxidising acids and in media containing ferric or cupric ions. C276 carries more molybdenum, which gives it a slight edge in the most aggressive reducing conditions. Both resist chloride pitting and stress-corrosion cracking.

What is Hastelloy C22 tube used for?

C22 is used in chemical and pharmaceutical reactors and heat exchangers, flue-gas desulphurisation and waste-incineration equipment, pulp and paper bleach plants, and offshore seawater and brine systems — particularly where the process combines chlorides with oxidising species.

What standards cover Hastelloy C22 tube?

Hastelloy C22 seamless tube is supplied to ASTM B622 / ASME SB622, with ASTM B829 covering general requirements and ASTM B619 / ASME SB619 applying to welded pipe.

Request a Hastelloy C22 Tube Quotation

Send your Seamless Hastelloy C22 Tube enquiry with grade, application, size (OD and wall thickness or schedule), quantity, length, end finish and inspection requirements. Our technical team will confirm availability, testing scope and lead time.

Request a Hastelloy C22 Tube Quotation