Multiple-wire submerged-arc welding technology for guaranteeing subsea pipeline steel pipe connector comprehensive performance

The invention discloses a multiple-wire submerged-arc welding technology for guaranteeing subsea pipeline steel pipe connector comprehensive performance, and belongs to the technical field of pipeline steel welding. The multiple-wire submerged-arc welding technology solves the problem that impact energy of 28.8mmX65MS pipeline steel pipe weld metal and fusion lines and connector rigidity cannot meet the engineering requirements. Welding of an inner weld joint and welding of an outer weld joint are completed by the adoption of automatic three-wire submerged-arc welding, a first wire of the inner weld joint, a second wire of the inner weld joint and a weld wire of the outer weld joint are H08C weld wires, and a third wire of the inner weld joint is an H08E weld wire; the diameter of the first wire and the diameter of the second wire are respectively 4.0mm, and the diameter of the third wire is 3.2mm. The bevel angle of a connector should be as small as possible, the base metal fusion ratio is improved, the comprehensive performance of the connector is guaranteed through weld joint attenuation by base metal, the bevel angle is chosen to be 60 degrees to 70 degrees, and a truncated edge of 8-10mm is reserved. According to the multiple-wire submerged-arc welding technology, through optimization of the bevel angle and different matching of weld materials, the harsh requirements for the comprehensive performance of the steel pipe welding connector of a subsea pipeline with the ratio of thickness to radial dimension being 0.0354 are met, and the technology is economical, simple and convenient to apply, easy to implement and beneficial to popularization.