An Overview of Ductile Iron Loose Flanged Fittings
Ductile Iron Loose Flanged Fittings provide a versatile and efficient solution for creating flanged connections without welding. They combine the mechanical strength of ductile iron with the assembly flexibility of a loose flange system, allowing for quick installation, easy adjustment, and reliable performance across a wide range of applications.
1. Material and Manufacturing
Core Materials:
Ductile Iron body (Grade 500-7 or higher) with spheroidal graphite structure
Flanges made from carbon steel (ASTM A36) or ductile iron
Gaskets: EPDM/Nitrile for water service, Viton for chemical applications
Bolts: Carbon steel (ASTM A307) or stainless steel (ASTM A193)
Manufacturing Features:
Precision-cast ductile iron body with grooved ends for gasket seating
Loose flanges slide freely over the pipe before final assembly
Machined flange faces to RF (Raised Face) or FF (Flat Face) standards
Corrosion protection via hot-dip galvanizing or epoxy coating
2. Performance Characteristics
Mechanical Performance:
Pressure rating: PN10/16/25 (150–300 psi class)
Temperature range: –30°C to 120°C (EPDM gaskets)
Angular deflection capability: 3–5° per joint
Vibration damping through rubber gasket design
Sealing Performance:
Double-sealing system:
Primary seal: Rubber gasket in socket groove
Secondary seal: Compressed flange gasket
Achieves zero leakage under test pressure (1.5× working pressure) and maintains integrity during soil movement or thermal expansion.
Installation and Adjustment:
Simple bolted connection—no welding required
Visual alignment verification before tightening
Adjustable pipe length compensation (±50 mm)
Reusable flange components
3. Utility and Applications
Primary Applications:
Water treatment facilities (pumps, filters, valves)
Industrial pipelines (cooling water, chemical processes)
Building services (HVAC, fire protection)
Municipal networks connecting to flanged systems
Installation Advantages:
40–60% faster installation vs. welded joints
Reduced labor costs (no certified welders needed)
Ideal for confined or maintenance-heavy areas
Fully reusable flange components
Technical Advantages:
Prevents electrolytic corrosion between metals
Absorbs vibration and compensates for thermal expansion
Eliminates weld heat-affected zones
Technical Specifications:
Standards: EN 545, EN 598, ISO 2531
Size Range: DN 80–600 (3″–24″)
Pressure Test: 2.5× PN rating
Bolt Torque: As per ASME B16.5
Conclusion:
Ductile Iron Loose Flanged Fittings deliver the strength of ductile iron and the adaptability of a modular system. They simplify installation, reduce costs, and offer excellent vibration resistance and reusability, making them ideal for modern, maintenance-oriented piping systems.
