Hastelloy C276 (UNS N10276) Large Diameter Forged Flanges | ASTM B564 Corrosion

Our Hastelloy C276 large diameter flanges are manufactured from fully forged ring blanks in accordance with ASTM B564, ensuring superior metallurgical integrity, structural uniformity, and long-term performance in aggressive service environments.

As a specialized forging manufacturer, we focus on producing heavy-section, large-diameter nickel alloy flanges for critical industrial systems where failure is not acceptable.

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Metallurgical Characteristics of UNS N10276

Hastelloy C276 is a Ni–Cr–Mo–W alloy engineered for exceptional resistance to both oxidizing and reducing media.

Typical nominal composition:

• Ni (Balance)

• Cr ~15–17%

• Mo ~15–17%

• W ~3–4%

• Fe ≤ 5%

Key performance advantages:

• Outstanding resistance to chloride-induced pitting and crevice corrosion

• Excellent resistance to stress corrosion cracking (SCC)

• Superior performance in wet chlorine, hypochlorite, and mixed acid systems

• Stable microstructure with low carbon content to prevent grain boundary carbide precipitation

Forged structure significantly enhances density and mechanical reliability compared to cast components.

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Forging & Manufacturing Process Control

Our large diameter C276 flanges are produced through:

1. Vacuum induction melting (VIM) or ESR refined billets (upon request)

2. Open-die ring forging to refine grain structure

3. Controlled deformation ratio to ensure uniform mechanical properties

4. Solution heat treatment with precise temperature control

5. CNC precision machining

6. 100% dimensional and NDT inspection

This process ensures:

• Refined grain flow following the ring contour

• Elimination of internal porosity

• Improved fatigue resistance

• Enhanced structural integrity under cyclic loading

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Dimensional Capability

We manufacture large diameter forged flanges with:

• Outer diameter: up to several meters (custom engineered)

• Heavy wall thickness capability

• ASME B16.5 / ASME B16.47 Series A & B

• Custom non-standard engineering drawings supported

Available types:

• Weld Neck Flanges

• Slip-On Flanges

• Blind Flanges

• Integral Forged Ring Flanges

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Mechanical Properties (Typical)

After solution annealing:

• Tensile Strength: ≥ 690 MPa

• Yield Strength: ≥ 283 MPa

• Elongation: ≥ 40%

Properties may vary depending on section thickness and heat treatment condition.

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Quality Assurance & Testing

To meet critical project requirements, we conduct:

• PMI (Positive Material Identification)

• Chemical composition analysis

• Tensile testing

• Hardness testing

• Ultrasonic testing (UT)

• Radiographic testing (RT) if required

• Dimensional verification with calibrated instruments

Full traceability documentation and Mill Test Certificates are provided.

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Application Fields

Our Hastelloy C276 forged flanges are engineered for:

• Offshore oil & gas platforms

• Chemical reactors and acid handling systems

• Flue Gas Desulfurization (FGD) units

• High-corrosion marine structures

• Chlor-alkali production lines

• Waste acid recovery systems