Threaded Flange

Description

Threaded flanges provide a mechanical pipe connection system that eliminates the need for welding, offering distinct advantages in applications where heat from welding is prohibited, frequent disassembly is required, or installation speed is critical. Featuring internal NPT (National Pipe Taper) threads, these flanges screw directly onto externally threaded pipe ends, creating a pressure-tight joint when properly assembled with thread sealant.

Technical Specifications & Standards:

Material Grades:

• Carbon Steel: ASTM A105 (Forged, Standard), A350 LF2 (Low Temperature)

• Stainless Steel: ASTM A182 F304/304L, F316/316L, F321

• Alloy Steel: ASTM A182 F11, F22 (available for high-temp service)

• Special Alloys: Monel, Inconel, Brass, Bronze for specific applications

Design & Manufacturing Standards:

• Dimensional Standards: ASME B16.5 (1/2″-24″), ASME B1.20.1 (NPT Threads)

• Pressure Classes: 150#, 300#, 600#, 900#, 1500#, 2500#

• Thread Types: NPT (National Pipe Taper) standard, BSPT available

• Facing Types: Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ)

• Hub Configuration: Typically thicker hub to accommodate thread depth

Critical Design Features:

• Internal Tapered Threads: 1:16 taper for self-sealing under pressure

• Reinforced Hub Design: Additional material to maintain strength after threading

• Thread Relief: Properly machined thread relief at back of flange

• Thread Quality: Class 2B or better thread fit for consistent sealing

• Alignment Capability: Can be rotated to any bolt hole orientation

Manufacturing Processes:

• Forging: Closed-die forging for structural integrity

• Heat Treatment: Normalized or Q&T per material requirements

• Machining: Precision CNC threading to exact NPT specifications

• Thread Inspection: Go/No-Go gauging for thread quality assurance

• Deburring: Careful removal of all thread burrs and sharp edges

Performance Characteristics:

• Pressure Rating: Generally lower than equivalent welded flanges

• Temperature Range: Limited by thread sealant compatibility

• Maximum Size: Typically limited to 4″ NPS for pressure applications

• Sealing Mechanism: Combination of thread interference and thread compound

• Reusability: Limited – threads can wear with repeated assembly/disassembly

Quality Assurance Protocol:

• Thread Inspection: 100% thread gauge verification

• Dimensional Verification: Full compliance with ASME B16.5

• Material Certification: MTRs with full traceability

• Surface Finish: Controlled facing finish for gasket sealing

• Marking: Clear stamping including thread specification