New t echnology of highly efficient automated submerged-arc welding of vertical site butt

Innovation technology - of highly efficient and cost-effective automated submerged-arc welding is designed for welding vertical site butt joints of span structures of bridges and large metal structures with plate thickness from 12 up to 50 mm by solid wire under a layer of molten slag with compulsory formation of the seam to two copper shoes. The developed new welding process leads to a considerable saving of power, essential lowering of the cost of welding consumables and improvement of operating efficiency. This technology combines a quiet running of the process, characteristic of electroslag welding with the high quality of metal of the weld and HAZ (heat-affected zone), that is usually provided only by flux-cored expensive wire welding. In addition, the submerged-arc welding process is characterized by much lower emissions of welding aerosol compared to welding by self- shielded flux-cored wire and welder’s labour hygiene.

Welding of metal structures of up to 50 mm thickness can be performed using raillessautomatic welding machine of type A-1150U   moving over the gap. In machine instead of the one-electrode welding head 2 electrode welding head with two mouthpieces and the flux-bunker for submission of a flux in a zone of welding is established. In which instead of the one-electrode welding head 2 electrode welding head with two mouthpieces and the flux-bunker for submission of a flux in a zone of welding is established. Welding speed of 10 m/h was achieved in welding of 20 mm steel at up to 800 A current. Welding of metal structures of greater thickness can be performed by appropriately modified vertical automatic welding machines mounted on vertikal rails of type AD-381, AD-348 type for welding with 2 foreign compulsory formation of a seam to two copper water-cooled shoes. At present the proposed technology has passed testing and has been introduced in welding (using flux of AN-67B grade) of vertical butt joints of span structures of a bridge across the Volga river in the city of Kineshma, and overpasses in Moscow and Tyumen.