The material produced by the spiral welded pipe(SSAW steel pipe) is a hot rolled coil, and the straight welded pipe is made of steel plate. The amount of alloy contained in the coil is less than that of the steel sheet. For this reason, the spiral welded pipe has higher weldability than the steel plate. The direction of the coil rolling is a certain helix angle, but the dry plate of the straight welded pipe is rolled in the straight direction with the axis of the steel plate, so the spiral welded pipe has better crack resistance.
The characteristic of the strength: the rotation angle of the spiral welded pipe weld is between 50-75 degrees, so the stress at the weld composition is 60-85 percent of the straight welded pipe. Therefore, if the two are under the same working pressure, the pipe wall of the spiral welded pipe can be reduced by two kinds of welded pipes of the same diameter.
If the spiral welded pipe is exploded, its explosion port will not appear in the weld, and its safety is higher than that of the straight welded pipe. Straight seam welded pipe is basically close to the common welding process. However, the straight seam welded pipe may have a T-weld weld during welding, which is a major welding defect, and the straight seam welded pipe of the T-weld is more likely to crack.
At this point, because of the different welding directions, the spiral welded pipe is very good to avoid this situation. The raw material and port cooperation scale of the field weldable steel pipe determines the weldability of the site. The spiral welded pipe is completed in the stable and continuous process under the same working condition in the production, but the straight welded pipe is different, and its production is carried out in stages.
This is also a big difference between the two. The welded seam of the spiral welded pipe is evenly distributed and the shape of the welded pipe is also very regular, so it is a good guarantee of the weldability of the weldability of the field in comparison with the straight welded pipe.
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