80 mm thick high-strength steel bridges MIG butt welding method

80 mm The method of butt welding steel bridges gas-thick high strength, comprising the steps: using Rm≥570MPa, ReL≥420MPa, elongation: A≥18%, - 40oCKV2≥120J, a thickness of 80? mm thick bridges and other steel butt; matching wire tensile strength ≥600? MPa, wire diameter Ф1.2mm; MIG V-groove double-sided symmetrical groove, groove angle of 60 °, the blunt edge of 2mm; current 262 ~ 270A, voltage of 26 ~ 28V, speed 28 ~ 29cm / min, an energy line 14 ~ 16kJ / using argon-rich shielding gas for the continuous welding cm, temperature control in the interlayer 100 ~ 110 ℃. Although the present invention has a thickness of up to 80 mm, and a butt joint using no preheating before welding, without heat treatment after welding, flaw detection was not found to have cracks, and the linker region of three -40oCKV2 impact energy reaches 145 ~ 260J, completely meet the technical requirements of large-span bridge structure bridge manufacture.