Stainless Steel 904L Flanges

What are Stainless Steel 904L Flanges?

Stainless Steel 904L flanges are high-performance piping components used to:

• Connect piping systems: Provide strong and leak-proof connections between pipes and equipment
• Handle aggressive environments: Ideal for highly corrosive chemical applications
• Enable easy maintenance: Allow dismantling for inspection and cleaning
• Ensure system reliability: Maintain integrity in critical industrial systems

These flanges are made from low-carbon, high-alloy austenitic stainless steel with added copper, offering superior resistance to corrosion compared to standard stainless steels.

Composition Highlights (Typical)

Stainless Steel 904L:

• Chromium (Cr): 19 – 23% → Enhances corrosion resistance
• Nickel (Ni): 23 – 28% → Improves toughness and stability
• Molybdenum (Mo): 4 – 5% → Provides resistance to pitting and crevice corrosion
• Copper (Cu): 1 – 2% → Enhances resistance to sulfuric acid
• Carbon (C): ≤ 0.02% → Prevents intergranular corrosion
• Iron (Fe): Balance

Key Advantage: High alloy content provides exceptional resistance to both oxidizing and reducing environments.

Key Features of Stainless Steel 904L Flanges

• Exceptional corrosion resistance: Performs well in highly aggressive environments
• Excellent resistance to acids: Especially sulfuric, phosphoric, and nitric acids
• Superior resistance to pitting and crevice corrosion
• High resistance to chloride stress corrosion cracking
• Good weldability and formability
• High strength and durability
• Long service life with minimal maintenance

Mechanical Properties

Stainless Steel 904L:

• Tensile Strength: ~490 MPa → High load-bearing capacity
• Yield Strength: ≥ 220 MPa → Resists deformation
• Elongation: ≥ 35% → Good ductility

These properties ensure reliable performance in demanding conditions.

Physical Properties

• Density: ~8.0 g/cm³ → Strong and durable
• Melting Range: 1300 – 1390°C → Suitable for high-temperature applications
• Modulus of Elasticity: ~200 GPa → High stiffness
• Thermal Conductivity: ~12 W/m•K → Lower heat transfer compared to standard SS
• Coefficient of Expansion: ~15 µm/m°C → Handles temperature variations

Corrosion Resistance

Stainless Steel 904L flanges offer outstanding resistance to:

• Strong acids: Sulfuric, phosphoric, nitric acids
• Chloride environments: Prevents pitting and crevice corrosion
• Seawater and marine conditions
• Stress corrosion cracking
• Industrial chemicals and solvents

This makes 904L one of the most corrosion-resistant stainless steels available.

Heat Treatment

• Annealing: 1090 – 1175°C
• Rapid cooling (water quenching)

This process enhances corrosion resistance and maintains ductility.

Weldability

SS 904L flanges can be welded using:

• TIG (GTAW) → Clean and precise welds
• MIG (GMAW) → Efficient for production
• SMAW → Suitable for industrial applications

Recommendations:

• Use low heat input
• Use suitable filler materials
• Maintain clean welding conditions

Machinability

• Moderate to low machinability due to high alloy content
• Use carbide tools
• Maintain low cutting speeds
• Apply adequate coolant to avoid overheating

Standards & Specifications

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

These standards ensure global quality compliance.

Available Types of Stainless Steel Flanges

• Weld Neck Flanges → High-pressure and high-temperature systems
• Slip-On Flanges → Easy installation
• Blind Flanges → Seal pipe ends
• Socket Weld Flanges → Small pipelines
• Threaded Flanges → Non-weld systems
• Lap Joint Flanges → Easy maintenance
• 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 and aesthetic finish
• Machined → Precision engineered

(Custom sizes available as per requirement)

Applications of Stainless Steel 904L Flanges

• Chemical Processing Industry: Used in acid handling systems and reactors.
• Oil & Gas Industry: Suitable for highly corrosive environments.
• Marine Industry: Used in seawater handling systems.
• Pharmaceutical Industry: Ensures corrosion-free and clean piping.
• Power Generation: Used in flue gas desulfurization systems.

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 examination → Detects defects
• PMI testing → Confirms material identity

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

Packaging & Delivery

• Export-quality wooden packaging
• Protective wrapping
• 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
• Strong export network
• Dedicated customer support

Conclusion

Stainless Steel 904L Flanges are a premium solution for industries requiring exceptional corrosion resistance in highly aggressive environments. Their superior chemical resistance, strength, and durability make them ideal for applications in chemical processing, marine, oil & gas, and power generation industries.

Virami Steel Hub offers high-quality SS 904L flanges that meet global standards, ensuring long-term reliability, safety, and performance.