Splicing and welding jig frame for steel box girders and splicing and welding process of splicing and welding jig frame

The invention relates to the technical field of steel box girder machining in railway systems, and particularly relates to a splicing and welding jig frame for steel box girders and a splicing and welding process of the splicing and welding jig frame. The splicing and welding jig frame comprises a horizontal frame for containing a bottom plate and a plurality of inclined rods for containing inclined plates, wherein the horizontal frame is horizontally arranged; the inclined rods are divided into two sets; the two sets of inclined rods are arranged at the top end of the horizontal frame; one end of each inclined rod is hinged to the horizontal frame, and the other end of each inclined rod is provided with a supporting rod; and one end of each supporting rod is hinged to the horizontal frame, and an adjusting device for adjusting the positions of the inclined rods and the supporting rods is arranged between the other end of each supporting rod and the corresponding inclined rod. According to the splicing and we