Metal connection type flue expansion joint

The utility model provides a metal connection type flue expansion joint, and belongs to the technical field of expansion joints. The metal connection type flue expansion joint comprises a supporting structure and a fixing structure. The supporting structure comprises two supporting pieces and a second connecting piece, one end of the first skin and one end of the second skin are installed on the two supporting pieces correspondingly, the second connecting piece is installed between the two supporting pieces, a clamping groove is fixed to one side of a second U-shaped clamping piece, and the other side of the second U-shaped clamping piece is fixed to the other side of the second U-shaped clamping piece. And a second magnetic sealing ring is fixed in the clamping groove, the first magnetic sealing ring and the second magnetic sealing ring are fixed in an adsorption mode, and the other end of the connecting piece is in threaded connection with the interior of the other third annular plate through a third connec