Views: 2 Author: Site Editor Publish Time: 2020-11-02 Origin: Site
Metallurgical properties of materials
The raw material for spiral welded pipe production is hot-rolled coil, and the longitudinal welded pipe is made of steel plate socket. The weight of the alloy contained in the coil is less than that of the steel plate. It is for this reason that the spiral welded pipe has higher weldability than the steel plate.
In addition, the rolling direction of the coil has a certain helix angle, but the dry plate of the longitudinal welded pipe is rolled along the direction perpendicular to the axis of the steel plate, so in comparison, the spiral welded pipe has better crack resistance.
Features in strength
The rotation angle of the weld of spiral welded pipe is between 50-75 degrees, so the stress at the weld joint is 60-85% of that of straight welded pipe. Therefore, if the two are under the same working pressure, the wall of the spiral welded pipe can be reduced for the two welded pipes with the same diameter.
So if a spiral welded pipe is blasted, its blasting hole will not appear in the weld, and its safety is higher than that of a straight seam welded pipe.
Welding process comparison
In the welding process, the welding of the two is basically close to the same. However, in the case of longitudinally welded pipes, T-shaped welds may appear during welding. This is a major welding defect. The longitudinally welded pipes with T-shaped welds are more likely to have cracks.
Due to the different welding direction at this point, spiral welded pipes can avoid this situation well.
The material of the steel pipe and the tolerance of the port size determine the weldability on site. Spiral welded pipe is produced in a stable and continuous process under the same working conditions, but the longitudinal welded pipe is different, and its production is carried out in stages.
This is also a big difference between the two. The welds of spiral welded pipes are distributed uniformly and the pipe shape of welded pipes is also very regular, so it follows with straight seam welded pipes to ensure the welding accuracy of field weldability.