UNS N06455|2.4610|Hastelloy C4 Seamless Pipe

Hastelloy C4 Seamless Pipes are high-performance cylindrical tubes manufactured from nickel-chromium-molybdenum alloy (UNS N06455), specifically engineered to deliver outstanding corrosion resistance in highly aggressive environments. With exceptional stability in strong oxidizing media, acidic solutions, and chloride-containing processes, these alloy pipes are widely used in chemical processing, flue gas desulfurization (FGD), nuclear, and petrochemical industries.

At Xinzhe, a professional manufacturer and supplier based in Wenzhou, China, we specialize in the precision production of Hastelloy C4 seamless pipes using advanced seamless forming and cold-finishing processes. Our pipes are available in a comprehensive range of outer diameters, wall thicknesses, and surface finishes, including both standard ASTM specifications and fully customized dimensions to meet specific project requirements.

Manufactured in compliance with international standards such as ASTM B622 and ASME SB622, our Hastelloy C4 seamless pipes offer excellent thermal stability, superior resistance to pitting and stress corrosion cracking, and long-term structural integrity under extreme temperature and pressure conditions.

To guarantee premium quality and reliability, each pipe undergoes rigorous inspection and testing procedures, including hydrostatic testing, eddy current testing, PMI (Positive Material Identification), and ultrasonic testing.

With strict quality control, competitive pricing, and reliable global delivery, Xinzhe has established a strong reputation as a trusted supplier of corrosion-resistant nickel alloy seamless pipes worldwide.

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What Is a Seamless Stainless Steel C4 Pipe?

ASeamless Stainless Steel C4 Pipe (more accurately classified as a Nickel-Chromium-Molybdenum Superalloy) is a high-performance piping solution designed for extreme chemical environments. Manufactured from a single solid billet, this seamless pipe offers unmatched structural reliability by eliminating the weld-seam vulnerability.

The"C4"(UNS N06455) designation is renowned for its exceptional high-temperature stability. Its ultra-low carbon and silicon content prevents the formation of grain-boundary precipitates in the heat-affected zone (HAZ), making it the gold standard for applications involving long-term exposure to temperatures between 1200°F and 1900°F (650-1040°C). Unlike other nickel alloys, C4 maintains its ductility and corrosion resistance even after significant thermal cycling.

Key Features and Technical Advantages

Ultimate High-Temperature Stability: The optimized chemistry minimizes embrittlement, ensuring the pipe remains tough and corrosion-resistant after processing or welding.
Versatile Corrosion Resistance: Outstanding performance in a wide array of aggressive media, including hot contaminated mineral acids, solvents, and chlorine-bearing environments.
Localized Corrosion Protection: High molybdenum content ensures superior resistance to pitting and crevice corrosion.
Stress Corrosion Cracking (SCC) Resistance: Inherently resistant to chloride-induced SCC, outperforming standard austenitic stainless steels.
Seamless Integrity: Provides uniform wall thickness and higher burst pressure ratings, essential for high-risk chemical transfers.

Product Specifications and Data

We provide C4 pipes compliant with global industrial specifications to ensure seamless integration into your infrastructure.

The composition of C4 is carefully balanced to achieve its superior corrosion resistance and high-temperature stability.

Stainless Steel C4 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.

Our production strictly adheres to international tolerance standards:

ASTM B622: Standard Specification for Seamless Nickel and Nickel-Cobalt Alloy Pipe and Tube.
ASTM B619 / B626: For welded counterparts and general requirements.
ASME SB622: Boiler and Pressure Vessel Code compliance.
DIN 17751 / ISO 6207: European and International specifications for seamless nickel alloy tubes.

Chemical Composition

C	Si	Mn	P	S	Cr	Mo	Ni	Ti	Cu	Co	Fe
≤0.015	≤0.08	≤1.00	≤0.04	≤0.03	14.00-18.00	14.00-17.00	Bal	≤0.70	≤0.50	≤2.00	≤3.00

Typical Mechanical Properties

Tensile Strength	Yield Strength	Elongation	Hardness
≥ 690 MPa	≥ 275 MPa	≥ 42%	≤ 100 HRB

Typical Physical Properties

Density	Melting Point	Thermal Expansion	Thermal Conductivity	Modulus of Elasticity	Electrical Resistivity
8.64 g/cm³	1335-1380 ℃	10.8 µm/m·℃	10.1 W/m·K	208 GPa	1.25 µΩ·m

Dimensional Standards and Tolerances

C4 seamless pipes are produced to international standards, ensuring high precision and engineering compatibility:

Standards Covered: ASTM B622 / ASME SB622 and ASTM B619 – 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.
Manufacturing Standards: production strictly adheres to ASTM, ASME and DIN 17751 tolerances.

Common Industrial Applications

Due to its unique metallurgical stability, C4 seamless pipe is the preferred choice for:

Chemical Processing

Reactors, agitators and piping systems handling hot acids and chlorides
Heat exchangers in strongly reducing and oxidising media

Pharmaceuticals

High-purity environments where intergranular corrosion must be zero
Piping resistant to cleaning chemicals and organic catalysts

Waste Treatment

Incineration scrubbers
Hazardous waste processing equipment

Pulp & Paper

Bleaching plants
Chlorine dioxide stages

Quality Assurance and Manufacturing Process

Every Hastelloy C4 (UNS N06455) 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 C4 vs Hastelloy C276 – Technical Comparison

Hastelloy C4 (UNS N06455) and Hastelloy C276 (UNS N10276) are Ni-Cr-Mo alloys. C4 was developed to offer improved thermal stability through very low carbon and silicon content, at a slightly lower level of corrosion resistance than C276.

Chemical and Metallurgical Differences

Carbon and silicon: C4 is limited to ≤ 0.015% C and ≤ 0.08% Si, minimising grain-boundary precipitation.
Chromium: 14.0–18.0% in C4 versus 14.5–16.5% in C276.
Molybdenum: 14.0–17.0% in C4 versus 15.0–17.0% in C276.
Tungsten: C4 is tungsten-free, unlike C276 which contains 3.0–4.5% W.

Thermal stability: C4 resists precipitation of intermetallic phases in the 650–1040°C range better than C276, retaining ductility after welding and thermal cycling.
Corrosion resistance: C276 provides slightly higher resistance to reducing acids, while C4 performs well in both oxidizing and reducing environments.
Applications: C4 is preferred where post-weld thermal stability is critical.

Selection Guide

ChooseHastelloy C4 for welded components exposed to elevated temperature and where ductility retention is essential.
ChooseHastelloy C276 for the most severe mixed-acid and chloride environments.
Both are supplied as seamless pipe to ASTM B622 / ASME SB622.

Ordering Information

Specify grade (UNS N06455) and standard (ASTM B622 / B619).
Provide OD × wall thickness, length and quantity.
State testing and documentation requirements.

Frequently Asked Questions

What is Hastelloy C4 seamless pipe?

Hastelloy C4 (UNS N06455) is a nickel-chromium-molybdenum alloy seamless pipe containing approximately 14.5–17.5% Cr and 14.0–17.0% Mo with no tungsten addition. Its tightly controlled carbon (0.015% max) and silicon (0.08% max) give it outstanding thermal stability and resistance to intergranular corrosion after welding.

What is the difference between Hastelloy C4 and C276?

C276 contains 3.00–4.50% tungsten and allows up to 7.0% iron, whereas C4 contains no tungsten and limits iron to 3.0% max. This makes C4 more thermally stable, with less intermetallic precipitation in the heat-affected zone, while C276 offers slightly better all-round corrosion resistance in the most aggressive mixed-acid environments.

Which standards cover Hastelloy C4 seamless pipe?

Hastelloy C4 seamless pipe is manufactured to ASTM B622 / ASME SB622 for seamless nickel alloy pipe and ASTM B619 / ASME SB619 for welded pipe, with ASTM B829 covering general requirements. Material is supplied with EN 10204 3.1 / 3.2 certification.

What is Hastelloy C4 pipe used for?

Typical applications include reactors, agitators and piping handling hot acids and chlorides in chemical plants, high-purity pharmaceutical environments where intergranular corrosion must be avoided, incineration scrubbers and hazardous waste processing, and chlorine dioxide stages in pulp and paper bleaching plants.

Ready to Request a Quotation?

Send your Seamless Stainless Steel C4 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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