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Installation of welded steel tube

Date:2018-04-20    View:927      Tag:Installation of spiral seam steel pipe


Installation of welded steel tube


1. repair the mouth

In order to ensure the welding quality, the welding is carried out before the complete inspection and correction, so that the pipe end, the oblique angle, the blunt edge and the roundness are in accordance with the interface size. When the individual steel pipe needs to be processed in the field, the gas welding is used and the slag is removed and the grinding wheel is reused with the grinding wheel.
The operation procedure of the counter is to check the size of the interface connector, to clean the cavity, to determine and adjust the longitudinal joint of the staggered position of the welded steel tube, to the first pipe straight, to adjust the size of the gap between the counterpart, to the leveling mouth, to straight to straight, to the light point welding.


2. welding
The interface is welded by arc welding. Once it is lowered to the base, it will survive for the two time. Each welding is welded once, and the arc welding of each layer will be stagger.


A. pipe joint should be prior to the mouth, slag, pipe end slot angle, blunt edge, gap, should conform to specifications; do not narrow gap welding in gap welding or welding methods.
The B. port should be flat with the wall, and the length of 300mm is arranged in order of the inner wall of the interface in order to close the wrong port, allowing the local check to be 0.2 times the wall thickness and not more than 2 millimeters.
The longitudinal and circumferential weld position of C. should conform to the following requirements: the longitudinal weld should be about 45 degrees to the vertical line of the pipe; the longitudinal weld of the welded pipe and the reinforcing ring should be interlaced, the distance should not be less than 100mm; the reinforcing ring section of the circumferential weld should not be less than 50mm; there should be no cross weld in any part of the pipe.
When D. positioning welding, all welding pad (or brand) should be positioned in the same way as the official welding, but the electrode diameter can be finely selected. The welding current of positioned welding shall be chosen to be larger than the formal welding current, usually 10%-15%, to ensure penetration.
E. pipe welding: the welding quality must conform to the relevant regulations of 4.2 in GB50268-97, the weld should be smooth, the width is uniform, the root runs through, there is no obvious concave and convex defect and edge phenomenon, the weld reinforcement should be higher than the tube surface about 2 mm, and weld the edge of the 2-3 millimeter groove.
F. pipe and flange welding, pipe should be inserted flange 2/3, flange and pipe should be vertical, the two overlap.
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