Background: Flange is an important component used in the connection between pipes or between pipe and equipment. It is widely used in mechanical industry

petrochemical industry and nuclear industry. Ordinary flange could be oxidized or corroded under high temperature and strong corrosion condition

which leads to flange’s failure.Purpose: The aim is to design and validate the double sealing flange which could be used in high temperature and strong corrosion condition stably and supplied as a reliable detachable connection for petrochemical industry and nuclear industry under high temperature and strong corrosion environment. Methods: New flange is designed using flexible graphite spiral wound gaskets and C style metal ring double sealing structure. The unique protection gas design ensures the graphite spiral wound gasket used in high temperature reliably. Test bed is built to verify the stability of the flange. Results: Pressure reducing of graphite spiral wound gasket is only 0.01 MPa at 750 oC

0.7 MPa for 43 h

there is not obvious oxidation phenomenon at the same time. The leakage rate of metal C sealing ring is 1.51×10–4atm cc/s

and the metal C ring sealing’s performance meets the engineering requirements.Conclusion: The leakage rate of double sealing flange is almost zero under 0.7 MPa at 750 oC

which meets the engineering requirements. It avoids oxidizing at high temperature and corroding under strong corrosion condition.