What should be paid attention to when flanges and pipes are welded?

1. flange contact surface should be smooth and smooth, allowing annular shallow grooves, but no scar, sand holes and radiation to the grooves.
　　2. flange center line should be perpendicular to the center line of the pipe, and the deviation is not greater than 1 - 2.5mm.
　　3. flange hole hole distance position (straight line measurement) allowable error 0.5--1.0mm.
　　4. the displacement error of the center line of the flange hole and the central line of the pipe is 1 to 2mm.
　　5. two flange plane allowable deviation 0.2--0.3mm.
　　6. when welding flange and pipe, stress and deformation (especially stainless steel) should be paid attention to.
　　To ensure that the flange and pipe perpendicularity, avoid two flanges in the bolt connection when the flange parallelism deviation is too large, resulting in gasket clip is not tight and produce leakage.
　　Many times, some projects do not allow on-site assembly, which requires us to assemble pipes and pipes ahead of time and then transport them to the construction site. These Custom pipeline save customers a lot of time.