Double-sided submerged arc SAWH steel pipe is that arc method is welding under flux layer, and formed is that the heat generated by the burning of the arc between the wire and flux in the flux layer and melting of the wire solder and base metal.As for the following reasons it is widely used in the production of large diameter steel pipe:
1, as long as the change of forming the angle, you can use the same broadband strip production of steel pipes of various calibres.
2, is a continuous bending and forming, so the length of steel pipe cut to length unrestricted.
3, weld spiral evenly distributed on the circumference of the entire steel pipe, steel pipe size, high precision, strong also higher.
4, easy to change the size suitable for small quantities of steel pipe production of many varieties.
Spiral seam weld is more length than a straight tube, tube length is L, the weld length is L / cos (θ) is the most concentrated of the steel tube defects in the weld and heat affected zone, weld length on the mean the probability of defects, which is the main reason for long-term restricting the spiral welded pipe more widely used, but also long-standing debate in the spiral and straight-seam pipe, especially compared with the UOE steel pipe superior, spiral pipe manufacturing technology to today, we should be comprehensive and correct evaluation and comparison, the idea of a long spiral weld, first of all, due to defects in the weld parallel, on the spiral, the weld defects oblique defects, in the course of the direction of the main stress of the steel pipe, or the equivalent defect length of the pipe axis direction than a straight seam pipe is small; Second, a larger pipeline steel are rolled steel plate, impact toughness to the opposite sex, than perpendicular to the rolling direction CVN value along the rolling direction of the CVN value is 3 times higher, straight seam pipe principal stress suffered precisely perpendicular to the minimum in the direction of the pipe impact resistanc.
