Fixing clamp for welding main steel structure

The utility model discloses a stationary fixture for welding of a main steel structure, which comprises a machining table, a mechanism box is fixedly connected to the bottom surface of the machining table, a power box is fixedly connected to the bottom surface of the mechanism box, a positive and negative screw rod is arranged in the mechanism box, two sliding blocks are arranged in the mechanism box, and the two sliding blocks are arranged in the machining table. Threaded grooves are formed in the side faces, close to each other, of the two sliding blocks correspondingly, the left end and the right end of the forward and reverse screw rod extend into the two threaded grooves correspondingly, the outer surface of the forward and reverse screw rod is in threaded connection with the inner walls of the threaded grooves, and two sliding holes are formed in the upper surface of the machining table. The inner walls of the two sliding holes are slidably connected with sliding blocks, and the bottom faces of the two