Internal plugging device for pipe welding

The invention provides an internal plugging device for pipe welding. The outer circumferential wall of a tray body is sleeved with a flame-retardant sleeve in a positioning mode, a flexible high-temperature-resistant fireproof sleeve with the section being of a U-shaped structure is arranged on the tray body, the flexible high-temperature-resistant fireproof sleeve wraps around the flame-retardantsleeve and abuts against the inner wall of a welding pipe, a protective gas supply device with the two ends communicating is arranged on the tray body, the gas outlet end of the protective gas supplydevice faces the welding position of the welding pipe, and a protective gas supply pipe used for supplying the gas to the welding position of the welding pipe is arranged inside the control end of the protective gas supply device located at the opening position of the welding pipe. According to the internal plugging device for the pipe welding, good high-temperature-resistant sealing conditions are provided for pipe plugg