Stainless Steel 347 Flanges

What are Stainless Steel 347 Flanges?

Stainless Steel 347 flanges are piping components used to:

• Connect pipelines: Provide strong, leak-proof joints between pipes and equipment
• Handle high temperatures: Ideal for applications involving continuous heat exposure
• Prevent corrosion: Especially intergranular corrosion after welding
• Enable maintenance: Allow easy dismantling for inspection and servicing

These flanges are made from niobium (columbium)-stabilized austenitic stainless steel, which enhances resistance to carbide precipitation.

Composition Highlights (Typical)

Stainless Steel 347:

• Chromium (Cr): 17 – 19% → Provides corrosion resistance
• Nickel (Ni): 9 – 13% → Enhances toughness and ductility
• Niobium (Nb/Columbium): ≥ 10 × (Carbon %) → Stabilizes structure
• Carbon (C): ≤ 0.08%
• Iron (Fe): Balance

Key Advantage: Niobium binds with carbon to prevent chromium carbide formation, ensuring excellent resistance to intergranular corrosion.

Key Features of Stainless Steel 347 Flanges

• Excellent high-temperature resistance: Suitable for continuous service in elevated temperatures
• Superior resistance to intergranular corrosion: Ideal for welded applications
• Good oxidation resistance: Performs well in oxidizing environments
• High strength and durability: Maintains structural integrity under stress
• Thermal stability: Reliable in cyclic heating conditions
• Good weldability: No need for post-weld annealing
• Long service life: Suitable for demanding industrial conditions

Mechanical Properties

Stainless Steel 347:

• Tensile Strength: ~515 MPa → High load-bearing capability
• Yield Strength: ≥ 205 MPa → Resists permanent deformation
• Elongation: ≥ 40% → Excellent ductility

These properties ensure reliability in high-temperature and pressure conditions.

Physical Properties

• Density: ~8.0 g/cm³ → Strong and durable material
• Melting Range: 1400 – 1450°C → Suitable for high heat applications
• Modulus of Elasticity: ~193 GPa → High stiffness
• Thermal Conductivity: ~16 W/m•K → Moderate heat transfer
• Coefficient of Expansion: ~16 µm/m°C → Handles temperature variations

Corrosion & Heat Resistance

Stainless Steel 347 flanges offer excellent resistance to:

• Intergranular corrosion: Especially after welding
• High-temperature oxidation: Ideal for furnace and heat systems
• Thermal cycling: Withstands repeated heating and cooling
• Mild chemical environments: Performs well in industrial applications

Heat Treatment

• Annealing: 950 – 1120°C
• Rapid cooling (air or water quenching)

This process enhances corrosion resistance and restores ductility.

Weldability

SS 347 flanges can be welded using:

• TIG (GTAW) → High-quality welds
• MIG (GMAW) → Faster welding process
• SMAW → Suitable for heavy industrial use

Recommendations:

• No post-weld heat treatment required
• Use compatible filler materials
• Maintain controlled heat input

Machinability

• Moderate machinability
• Use carbide or coated tools
• Maintain low cutting speeds
• Apply sufficient coolant to reduce heat buildup

Standards & Specifications

• ASTM A182
• ASME SA182
• ANSI B16.5
• ANSI B16.47
• ASTM A240

These standards ensure consistency, quality, and global acceptance.

Available Types of Stainless Steel Flanges

• Weld Neck Flanges → High-pressure applications
• Slip-On Flanges → Easy to install
• Blind Flanges → Close pipe ends
• Socket Weld Flanges → Small-diameter systems
• Threaded Flanges → Non-weld systems
• Lap Joint Flanges → Easy dismantling
• Orifice Flanges → Flow measurement

Sizes & Specifications

• Size Range: ½ inch to 48 inches
• Pressure Class: 150#, 300#, 600#, 900#, 1500#, 2500#
• Type: Forged

Surface Finish:

• Pickled → Clean and corrosion-resistant
• Polished → Smooth surface finish
• Machined → Precision engineered

(Custom sizes available as per requirement)

Applications of Stainless Steel 347 Flanges

• Aerospace Industry: Used in high-temperature exhaust and structural systems.
• Heat Treatment Industry: Applied in furnaces and thermal processing equipment.
• Chemical Processing: Suitable for high-temperature chemical environments.
• Oil & Gas Industry: Used in high-heat and pressure systems.
• Power Generation: Ideal for boilers and heat exchangers.

Quality Testing & Inspection

All flanges undergo strict quality checks:

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

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

Packaging & Delivery

• Export-quality wooden packaging
• Protective wrapping to prevent damage
• Proper labeling and traceability
• Safe and timely global shipping

Why Choose Virami Steel Hub?

• Trusted SS flange manufacturer in Mumbai
• Large stock availability
• Competitive pricing
• Custom manufacturing solutions
• Compliance with international standards
• Global export expertise
• Dedicated customer support

Conclusion

Stainless Steel 347 Flanges are an excellent choice for high-temperature applications requiring resistance to intergranular corrosion. Their niobium stabilization ensures superior performance in welded and heat-exposed environments, making them ideal for industries such as aerospace, chemical processing, oil & gas, and power generation.

Virami Steel Hub provides premium-quality SS 347 flanges that meet global standards, ensuring long-term reliability and performance.