Electric welding machine for welding steel pipes

The electric welding machine comprises a machine frame, two clamping assemblies used for clamping the steel pipe and a welding assembly used for welding the steel pipe, the two clamping assemblies are distributed in the length direction of the machine frame, and each clamping assembly comprises two abutting pieces; the two abutting parts are distributed in the length direction of the rack, each abutting part comprises an abutting ring, a plurality of abutting rods and a rotating ring, the abutting rings are arranged on the rack, the abutting rods are slidably connected to the abutting rings in the radial direction of the abutting rings, the abutting rods are used for abutting against a steel pipe, and the rotating rings are arranged on the abutting rings. The rotating ring and the abutting ring are coaxially arranged, the rotating ring is rotationally connected to the abutting ring, a plane spiral groove is formed in the rotating ring, and the abutting rod is connected to the plane spiral groove in a sliding