Valori di coppia dei bulloni delle flange Tabella completa per tutte le classi di pressione

Proper Flange Bolt Torquing Guide

Correct bolt torque is critical for achieving leak-free flange joints. Under-torquing causes gasket blowout, while over-torquing can damage gaskets or warp flange faces.

Perché la coppia dei bulloni è importante

• Ensures uniform gasket compression
• Prevents flange leakage under operating conditions
• Compensates for gasket creep and relaxation
• Maintains joint integrity during thermal cycling

Class 150 Bolt Torque Values (ft-lbs)

Dimensione	Dimensione del bullone	Quantità	Non-Lubricated	Lubricated
1/2″	1/2″-13	4	45	35
1″	5/8″-11	4	85	65
2″	3/4″-10	4	150	115
4″	5/8″-11	8	85	65
6″	3/4″-10	8	150	115
12″	7/8″-9	12	250	190

Class 300 Bolt Torque Values (ft-lbs)

Dimensione	Dimensione del bullone	Quantità	Non-Lubricated	Lubricated
1/2″	1/2″-13	4	65	50
2″	3/4″-10	8	185	140
4″	3/4″-10	8	185	140
6″	7/8″-9	8	290	220
12″	1″-8	12	425	320

Class 600-2500 Torque Guidelines

Higher pressure classes require significantly higher torque values. Always refer to manufacturer specifications for Class 900, 1500, and 2500 flanges.

Bolt Torquing Procedure

1. Clean: Remove dirt, rust, and old gasket material from flange faces
2. Inspect: Check flange faces for damage or warping
3. Lubricate: Apply anti-seize compound to bolt threads and nut faces
4. Insert: Place gasket centered on flange face
5. Hand-tighten: Snug all nuts finger-tight
6. Pattern: Use star/cross pattern for even compression
7. Sequence: Torque to 30%, then 60%, then 100% of final value
8. Verify: Recheck all bolts after initial torque

Important Considerations

• Gasket Type: Different gaskets require different compression loads
• Bolt Material: ASTM A193 B7 vs B16 have different strength ratings
• Lubrication: Reduces required torque by 20-25%
• Temperature: Hot torquing may be required for high-temperature service
• Re-torquing: Consider re-torquing after thermal cycles

Errori comuni da evitare

• Using impact wrenches without calibration
• Torquing in circular pattern instead of star pattern
• Skipping the multi-step torque sequence
• Reusing damaged or stretched bolts
• Ignoring gasket manufacturer torque recommendations

Proper bolt torquing is essential for leak-free flange joints. Always follow established procedures and use calibrated torque tools.

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