1) Choosing the correct welding sequence according to different forms of port slope
Longitudinal welded steel pipe can be welded on both sides of the case. Most grooves can be welded according to the first weld plate, then the transition layer is welded, and the welding cladding is finally customized. Tilt both sides of the slag mouth and clean with the same material plate cut by wire brush or grinder bottom.  The longitudinal welded steel pipe must be discharged and the electrodes should not swing horizontally. If there is only one side welding, the welding seam cladding can only re-weld the transition layer, and the sequence of the substrates is welding seam after welding. However, before submerged arc welding, the thick-walled steel pipe needs to take additional protective measures, such as filling the weld with protective gas. In addition, in the layered beads, the thickness of the weld must be strictly controlled, not too thick.


(2) Strict control of weld penetration
LSAW pipeline penetration welding process is difficult to determine the size. In operation, welders often indirectly determine the size of penetration according to the current size and the size of plating solution. Normally, the fusion depth buffer layer and the flange of the base plate are also between 1.5 and 2.5 mm. The welding seam is clad, and the fusion depth covers the transition between the welding seam and the gap between 0.5 and 1.0 mm.


When the outer space position of LSAW steel pipe is large and the welding point platform is close to it, magnetic flux gravity feeding or pressure proportioning is usually used.


The new flux from the flux funnel can be rotatably applied to the pressure feeding tank, which is conveyed to the pressure transmission pressure at the lower part of the flux separator, and then to the middle of the transition hopper, where gravity is applied to the welding area. After the use of large-caliber thick-walled fluxes, the source-backflow splitter produced by vacuum suction is then flowed from the middle of the transition pipe to the bucket, and then to the welding area for reuse. There is a variant of this double-sided SAW pipeline flux recovery conveyor. It cancels flux pressure of transfer tank. The weight of flux flux flow through the upper part of the new complementary flux diverter is always the loss of supplementary flux. Transfer flux recovery is usually automatic. In the high quality requirement of flux recovery, a screening and magnetic separation device is added at the flux outlet of the separator to recover flux purification treatment.