DSAW pre-welding technology

LSAW pre-welding technology in the pipeline construction, oil and gas pipelines is toward large-diameter high pressure transmission and submarine pipelines thick direction of development, a growing number of pipeline requests using DSAW steel pipe. As China's few Tachih submerged arc welded pipe production line imported production, LSAW grasp advanced welding technology is particularly important.

Pre-welding technology status
Presoldering LSAW steel pipe welding work is part of the seam along the length of it forming a "shallow weld" is LSAW pipe production is one of the special process. In the early years of LSAW pipe production is not pre-welded, welded pipe mill until the second-generation uoe began to emerge in pre-welder, but this time the pre-welded to intermittent welding, spacing of about 300mm, welded steel tube mill to uoe Development of the third generation, pre-weld has been greatly focused and development, has gradually form into another form is not at this stage of the pre-welding technology welding technology for the contemporary pre-foundation.

Pre-process welding work
Presoldering, the first steel tube for commissure, followed by another gas shielded arc welding, seam welding conditions and simultaneous welding quality monitoring and feedback. Specific work process: to accept imports of roller tube - adjust the seat tube opening - Conveying Equipment delivery tube tube leaves commissure - confirm commissure quality - preliminary welding torch landed - start tracking laser tracker - open the protective gas and the cooling water valve - start welding (welding speed tube to feed) _ - to stop the terminal arc welding - Hysteresis Shutdown Protection Gas - torch rising return - pass tube down procedure. This, a pre-weld cycle is completed. In the above process, adjust seat tube opening, refers to the openings on the seat adjusted to request seats, seat ordinary is 12 o'clock, this work can be electrically controlled system camera surveillance system. Confirm commissure quality, is on the wrong side seam of the amount recognized in the seam gaps, etc., can be confirmed as long as the tracking and weld seam. In order to ensure the welding quality of the welding starts, check the specific use of the torch, clean spatter on the torch may be appropriate to spray some anti-spatter agent. Pre-welding arcs and arc-quenching ordinary Kai Kai arc board and board for extinction. Approximately 80mm tube end forming within the scope of the pre-welding seam by hand after the end of GMAW welding.