The production, shaping and welding of spiral submerged arc welded pipe are carried out at the same time, so the stability of welding quality is inseparable from the formation of spiral submerged arc welded pipe. Forming seam recedes and flows, "pucker", tight and loose inside, loose outside, partial staggered edge pitching, extruding thick side plate, lack of notches, waves, burrs and irregular pore inclined surface, resulting in adverse and weld undercutting, burnout, pore, slag and other defects. Therefore, we find it necessary to adjust the forming instability in time.


The welding quality and chemical composition of flux, viscosity, bulk density, particle size and stacking height of spiral submerged arc welded pipe are closely related to the external influence and control of weld shape.


The chemical composition and viscosity of flux have a great influence on the weld. Although the flux of each manufacturer meets the GB/T 5293-1999 standard, its metallurgical and technological properties are different due to its formulation. When choosing, we can observe, test, analyze and compare to choose the best candidate. The choice of flux should ensure that you have good metallurgical and technological properties, stable arc furnace slag with appropriate melting point, viscosity and surface tension, and good welding, easy slag removal, less toxic gas.


It is generally believed that the flux has low viscosity, which improves the fluidity of slag and makes the welding good. High viscosity flux causes no ripple in the weld, but forming defects. When special low melting point solder is used, the flux has high melting ability, and the surface pressure of the weld pool is high, which makes it difficult to precipitate gas. The gas concentrates under the slag and makes the weld unstable. In order to obtain a good weld, the slag thickness around the arc chamber should be right, and the viscosity should be moderate with the change of temperature.