Automatic welding machine wire feeding device for build up welding of minor-diameter pipe die inner wall

The invention discloses an automatic welding machine wire feeding device for build up welding of the minor-diameter pipe die inner surface. A threaded connecting pipe, a wire feeding pipe, a steel connecting piece, a simmer bending device and a copper variable-diameter connecting pipe are additionally arranged between an original wire feeding mechanism and a welding nozzle of a welding machine. Inthe welding process, welding wires pass through a wire feeding mechanism, the threaded connecting pipe, the wire feeding pipe and the simmer bending device and then are output from the welding nozzle. The automatic welding machine wire feeding device goes deep into a minor-diameter pipe die, a control system of the automatic welding machine is started, welding fluid and the welding wires are fedin, and build up welding is started. In the build up welding process, the pipe die is rotated, the wire feeding device is fed forwards along with an automatic welding machine platform, and thus automatic build up welding of th