Based on new technical standards and construction characteristics,an automatic flow production line for long rail welding is set up at the track base of the passenger transport line,and the key technologies are summarized for long rail spark contact welding.

The welding of billets was simulated on UN 100 preheat flash welding machine for 20MnSi steel, the rolling experments was performed on φ300 mill, then the hardness and structure of the welded joint after deformation was studied.

The weld is required to have similar properties as the matrix of the bar and wire produced by endless rolling process The welding of 20MnSi steel was simulated with UN 100 preheat flash welding machine,the rolling experiments was carried out on φ300 mill,the influence of elongation coefficient on the structure,plasticity and toughness of the weld was studied.

The 20MnSi steel blank high temperature welding was simulated by UN-100 preheat flash welding machine for the rolling was performed on φ 300 mill, then the influence of upset force on the structure, plasticity and toughness of the welded area was studied.

Design all adoptions HRB400 reinforcing bar(x-rated steel),under construction adoption roll-press thread connect,electricity pressure weld,flashlight weld,electricity weld takes to connect with colligation takes to connect various conjunctions method.