Spiral steel pipe (SSAW) is a spiral steel pipe made of strip steel or coiled plate in a spiral shape, and double-sided submerged arc active welding for inner and outer seams. It is widely used in the production of water, electricity, chemical industries and other industries: Only by changing the forming point of view, steel pipes of various diameters can be produced from strip steel of the same width, which is easy to adjust.
Because it is formed in successive twists and turns, the length of the spiral tube is not restricted, and the length can be set at will. The spiral shape of the welding seam is evenly distributed on the circumference of the spiral tube, so the spiral tube has high dimensional accuracy and strong strength. It is easy to change the scale and is suitable for the production of small batches and various types of spiral pipes.
The weld seam of the spiral steel pipe is longer than the weld of the same standard straight seam pipe. Under the same standard wall thickness, the spiral steel pipe can receive the greatest pressure. The disadvantage of the welded seam of the spiral steel pipe is the "oblique defect". During use, the main stress direction of the steel pipe, that is, the equivalent defect length in the axial direction of the steel pipe is smaller than that of the straight seam pipe
; secondly, because the pipeline steel is all rolled steel plate, The impact toughness has a large anisotropy, and the CVN value in the rolling direction can be 3 times higher than the CVN value perpendicular to the rolling direction.
In order to get used to the needs of modern production, the steel structure workshop was born upon invitation. Compared with the pre-component workshop, the steel structure workshop has the following advantages, short production time and low production price. The general steel structure workshop includes steel columns, steel beams, steel structure foundations, steel roof trusses, steel roofs, steel columns used channel steel in the past few years. In recent years, people have discovered the defects of channel steel in construction, and gradually use spiral steel pipes. Instead of channel steel.
Spiral steel pipes have the following advantages in steel structure workshops. Spiral steel pipes have strong habitual standards, which means that any standard can be produced by spiral steel pipes. The length of spiral steel pipes can also be arbitrary, and the longest can be up to 30 meters. It can also be made into a conjoined pillar, which has better function than channel steel and is cheaper.