Friday, October 17, 2014

Seamless steel tube for pipeline engineering welding techniques

Steel pipe transported to the site, firstly according to equipment and fittings position pipes, and in the field will be specific length of each pipe of measurement is good, mark the specific size and arrangement of the position, so that when the interface condemnation, the use of lower crane tube, down tube process be used in nylon lifting sling to pipe insulation protection.

Dual control heating pipes, under normal circumstances can reduce 25% of project cost (using FRP do protective layer) and 10% (high-density polyethylene made ​​protective layer) around. Pipe shall have a cross weld anywhere. When tack welding, weld all electrode positioning number (or grade) should be formally welding the same, but some fine electrode diameter optional. Positioning the welding current is selected from the weld becomes larger than the time of welding, is usually 10% -15% larger, in order to ensure penetration. For pipe welding, the weld should be smooth, uniform width, root penetration, no obvious defects and undercut bump phenomenon, should be above the pipe welds to strengthen the surface area of ​​about 2 mm, welding the groove edge 2-3 mm. When the pipe and flange welding, pipe flanges should be inserted thirds, flange and pipe should be perpendicular to the axis of the two coincide.

a, horizontal pipe slope of not less than 0.3%.
b, should be checked before welding welding environment, welding installation equipment, welding materials, and dry cleaning, must comply with the specifications and requirements of welding operations.
c, welding pieces of double-sided welding, weld root should be cleaned and checked back, after cleaning up the defect before welding seam on the back. The provisions of gouging welds should be visually inspected after gouging before welding.
d, the wall of the pipe must fight more than 4mm groove before welding, bevel surface may not have dissection, cracks, damage processing, burrs and flame cutting slag and other defects. After coating should knock welding clean, weld should be rendered uniform scaly, without pores, slag, cracks, welding tumor and other phenomena, biting flesh length should be within specifications.

No comments:

Post a Comment