Connecting piece applied to internally-expanded groove pipe

The invention discloses a connecting piece applied to an internal expansion groove pipe, which comprises a buckling part which extends into an internal expansion groove from a positive groove opening of the internal expansion groove of the internal expansion groove pipe, a connecting part which extends out of the positive groove opening of the internal expansion groove is arranged on the buckling part, and after the connecting part drives the buckling part to rotate by an angle, the internal expansion groove vertically limits the buckling part. And the buckling part and/or the connecting part are/is provided with a rotated positioning piece which is used for driving the buckling part which is rotated by an angle to fasten the internal expansion groove and positioning the buckling part in the vertical direction and the rotating direction. The connecting piece has the advantages of being simple and ingenious in structure, convenient to install and capable of achieving positioning and rotation prevention. 本发明公开了