Welding technology of large diameter spiral steel pipe weld

With the continuous development of oil and gas pipelines to large diameters and high pressures, spiral submerged arc welded steel pipes also continue to develop to large diameters, large wall thicknesses and high steel grades. The double-wire submerged arc welding process plays an increasingly important role in the production of spiral welded pipes.

This article mainly studies the relationship between the double wire penetration depth and the groove form and welding parameters, and uses regression analysis to find the parameters such as the double wire submerged arc welding penetration depth and welding current, arc voltage, welding speed, joint groove shape, etc. The empirical formula for the relationship between.

This article first analyzes the influence of the parameters of double-wire submerged arc welding on the weld penetration. It is found that welding current, arc voltage, welding speed, welding wire diameter, groove shape, welding wire inclination, double wire spacing and other parameters all affect the double wire The penetration depth of spiral submerged arc welding, and the main influencing factors are: welding current, welding speed and groove shape.

We also studied the influence of spiral submerged arc welding external welding groove angle on weld penetration, mechanical properties and appearance quality through experiments. The test results show that as the external welding groove angle increases, the external weld height decreases significantly , The outer welding penetration depth has been significantly increased. For X80 steel grade 18.4mm wall thickness spiral submerged arc welded steel pipes, the impact toughness of the weld is slightly improved, and the impact toughness of the heat affected zone is reduced.

Finally, through the long-term accumulation of data on the relationship between the double-wire welding penetration and welding current, welding speed, and groove shape in the production process of spiral submerged arc welded steel pipes, regression analysis was used to find the relationship between the double-wire welding penetration and the above welding parameters. The empirical formula for the relationship. Subsequent production process weld acid etching samples show that the empirical formula can be applied to the double-wire spiral submerged arc welding process.