How to Tighten LGF-PA66 Flange Bolts Without Damaging the Flange?

PA66 flanges are moulded as one piece with the body. They carry normal pipeline loads well but do not tolerate point loading the way steel flanges do — the tightening method decides whether a flange survives.

Key points:

• Flange dimensions follow GB/T 9119, so bolt patterns match standard pipeline flanges with no adapters;
• Tighten diagonally in stages: 30%, then 60%, then final torque. Use a calibrated torque wrench; never an impact wrench;
• Torque values depend on size (DN15–DN300) — follow the torque table in the manual or request it from the technical team;
• Gaskets: full-face rubber or PTFE-envelope types; avoid undersized ring gaskets that concentrate stress;
• No hot work: never use the body as a welding ground or weld near the meter.

After installation, fill the line slowly to vent air, then raise pressure gradually and check the flange faces for leaks. During pipeline hydrostatic testing, isolate the LGF-PA66 — test pressures above the rated value damage both liner and body.

For more details, visit our product pages or contact the technical team.