Hastelloy C-276 / C22 Alloy Flanges

What are Hastelloy C-276 / C22 Alloy Flanges?

Hastelloy C-276 and C22 flanges are high-performance piping components used in critical industrial systems.

• Connecting piping systems: These flanges join pipes, valves, pumps, and equipment, ensuring a strong and secure connection.
• Leak-proof sealing: When combined with gaskets and bolts, they prevent leakage even under high pressure.
• Handling aggressive environments: Designed to work in extreme chemical and acidic conditions.
• Ease of maintenance: Allow easy dismantling for inspection, cleaning, or replacement.

They are made from nickel-based alloys known for their exceptional resistance to corrosion in both oxidizing and reducing environments.

Composition Highlights (Typical)

Hastelloy C-276:

• Nickel (Balance): Provides base corrosion resistance and toughness
• Chromium (14.5–16.5%): Protects against oxidation
• Molybdenum (15–17%): Enhances resistance to pitting and crevice corrosion
• Iron (4–7%): Improves structural strength
• Tungsten (3–4.5%): Boosts resistance to severe chemical environments

Hastelloy C22:

• Higher Chromium (20–22.5%): Offers superior resistance in oxidizing environments
• Molybdenum (12.5–14.5%): Provides strong pitting resistance
• Tungsten (2.5–3.5%): Improves durability in harsh conditions

Key Difference:

• C-276 → Better for reducing environments
• C22 → Better for oxidizing environments

Key Features of Hastelloy C-276 / C22 Flanges

• Exceptional corrosion resistance: Performs well in highly aggressive chemicals and acids
• Resistance to pitting and crevice corrosion: Prevents localized damage in chloride environments
• Performance in oxidizing and reducing conditions: Versatile for multiple chemical processes
• High resistance to stress corrosion cracking: Reduces risk of sudden material failure
• High strength and durability: Suitable for heavy-duty industrial use
• Good weldability: Can be fabricated easily without compromising properties
• Long service life: Reduces maintenance and replacement costs

Mechanical Properties

Hastelloy C-276:

• Tensile Strength (~690 MPa): Indicates the ability to withstand pulling forces
• Yield Strength (≥ 283 MPa): Shows resistance to permanent deformation
• Elongation (≥ 40%): Reflects flexibility and ductility

Hastelloy C22:

• Higher Yield Strength (≥ 310 MPa): Better resistance to deformation
• Higher Elongation (≥ 45%): Improved flexibility and formability

Physical Properties

• Density (~8.69 g/cm³): Provides strength with manageable weight
• Melting Range (1325–1370°C): Suitable for high-temperature applications
• Modulus of Elasticity (~205 GPa): Indicates stiffness and resistance to deformation
• Thermal Conductivity (~10 W/m•K): Low heat transfer, suitable for controlled environments
• Thermal Expansion (~12.4 µm/m°C): Handles temperature variations effectively

Corrosion Resistance

Hastelloy C-276 / C22 flanges offer outstanding resistance to:

• Strong acids: Such as sulfuric, hydrochloric, and nitric acids
• Chloride corrosion: Prevents pitting and crevice corrosion in saline environments
• Oxidizing environments: Especially effective for C22 grade
• Reducing environments: C-276 performs exceptionally well
• Chemical solvents: Suitable for complex industrial chemicals

These alloys are among the most corrosion-resistant materials available.

Heat Treatment

• Solution Annealing (1040–1150°C): Restores corrosion resistance and ductility
• Rapid Cooling: Prevents unwanted carbide formation and maintains structure

This process ensures optimal performance in harsh conditions.

Weldability

Hastelloy alloys can be welded using:

• TIG (GTAW): Provides clean and precise welds
• MIG (GMAW): Suitable for faster fabrication
• SMAW: Common for industrial applications

Best Practices:

• Use matching filler materials
• Maintain low heat input
• Ensure a clean welding environment

Machinability

• Moderate machinability: Requires proper tooling
• Use carbide tools: Improves cutting efficiency
• Low cutting speeds: Prevents overheating
• Coolant usage: Reduces tool wear and improves finish
• Avoid work hardening: Important for maintaining surface quality

Standards & Specifications

• ASTM B564: Standard for forged Hastelloy flanges
• ASME SB564: Equivalent ASME specification
• ANSI B16.5 / B16.47: Defines dimensions and pressure ratings
• ASTM B575: Material standard

These ensure global quality and compatibility.

Available Types of Hastelloy Flanges

• Weld Neck Flanges: Designed for high-pressure and high-temperature systems
• Slip-On Flanges: Easy to install and cost-effective
• Blind Flanges: Used to close pipe ends
• Socket Weld Flanges: Suitable for small-diameter, high-pressure lines
• Threaded Flanges: Ideal where welding is not possible
• Lap Joint Flanges: Used where frequent dismantling is required
• Orifice Flanges: Used for flow measurement applications

Sizes & Specifications

• Size Range (½” to 48”): Suitable for various pipeline sizes
• Pressure Ratings (150# to 2500#): Handles different pressure requirements
• Forged construction: Ensures strength and reliability

Surface Finish:

• Pickled: Clean, corrosion-resistant surface
• Polished: Smooth and aesthetic finish
• Machined: Precision-finished surfaces

Applications of Hastelloy C-276 / C22 Flanges

• Chemical Processing Industry: Used in reactors, pipelines, and acid handling systems.
• Oil & Gas Industry: Handles corrosive fluids and harsh environments.
• Pharmaceutical Industry: Used in clean and contamination-free systems.
• Power Generation: Applied in flue gas desulfurization units.
• Marine Industry: Suitable for seawater and salt-rich environments.

Quality Testing & Inspection

Each flange undergoes strict quality checks:

• Chemical testing: Ensures correct alloy composition
• Mechanical testing: Verifies strength and durability
• Dimensional inspection: Confirms accuracy
• Surface testing: Detects defects
• PMI testing: Confirms material identity

Mill Test Certificates and third-party inspection reports are provided.

Packaging & Delivery

• Strong wooden export packaging
• Protective wrapping to prevent damage
• Proper labeling for traceability
• Safe and timely global delivery

Why Choose Virami Steel Hub?

• Reliable manufacturer in Mumbai
• Wide stock availability
• Competitive pricing
• Custom manufacturing options
• Compliance with international standards
• Strong global export network
• Dedicated customer support

Conclusion

Hastelloy C-276 / C22 Alloy Flanges are highly reliable solutions for industries requiring superior corrosion resistance in extreme environments. Their ability to perform in both oxidizing and reducing conditions makes them indispensable in chemical processing, oil & gas, marine, and power generation industries.

Virami Steel Hub delivers high-quality Hastelloy flanges that ensure durability, performance, and long-term value.