Abstract: Leakage occurred in the pipe plug of the tube bundle of air cooler in an oil refinery during the start-up of the unit and individual pipe plugs were found to be fractured during the tightening process. Through macroscopic inspection, chemical composition analysis and metal testing of the fractured pipe plugs and the new pipe plugs of the same batch, the causes for the fracture were identified. Meanwhile, solutions were proposed with reference to peer cases. This paper can provide ideas and reference for solving related problems in similar equipment.

Key words: air cooler, pipe plug, fracture