Detection system and detection method for hot-state pipe diameter of bell and spigot metal pipe

The invention relates to a bell and spigot metal pipe thermal-state pipe diameter detection system and method, and the system comprises a bell and spigot metal pipe, a fixed seat, a linear rail which is fixed on the fixed seat and is located at the axial outer side of a bell end face, and the projection of the linear rail on the plane where the bell end face is located penetrates through the inner circle of the bell end face, the length of the linear rail is larger than the diameter of the outer circle of the end face of the socket. The laser sensor is located on the linear track and linearly reciprocates by means of the linear track, and the laser emitting direction of the laser sensor faces the end face of the bell mouth and is parallel to the axis of the bell and spigot metal pipe; the device and the method have the beneficial effects that in the aspect of thermal-state cast pipe detection, the specification of a thermal-state nodular cast iron pipe is judged in a manner of laterally judging a shielding ob