The large-scale welding workstation specially designed for heavy-duty box beam structures is the first in China, which is equipped with a ring-shaped and C-shaped turning mechanism, the maximum load and turning weight is 60 tons, and the maximum diameter of the workpiece is 6m and the longest is up to 30m, . The two stations share an 80-meter-long rail, forming a complete workstation with two sets of gantry-type welding robots. The positioner is convenient to use and can be easily opened or disassembled, and the heavy-duty card can easily adjust the size to adapt to various sections of box-shaped structural beams. It is suitable for efficient welding of inner and outer welding seams, while taking into account the outer T-shaped steel, flange plate, horizontal channel steel (or angle steel), etc. AAdditionally, it ensures that the fixture has sufficient anti-collision capability when lifting the workpiece onto the flipping fixture.