H-beam automatic welding machine There lha gantry type, lhc cantilever type automatic welding machine and lht double column-beam automatic welding machine. It adopts a.C.Inverter control, with functions of stable running and fast traveling speed; the seam-tracking arc-guide mechanism is three-spindle system to guarantee the alignment without aberrancy; the main frame and welding machine are intergrated control, with flux auto-recovering system and it is easy to operate with high efficiency. Lht double column-beam automatic welding machine can weld two pieces of beam at the same time, and the web height of beam is not limited by main machine.