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Spiral submerged arc welded pipe

更新日期:2013-06-18  浏览:1618

Introduction for commonly used steel - spiral submerged arc welded steel

Bending the strip steel as spiral shape and using automatic submerged arc welding joints and welding seam into spiral seam steel pipe. waterway construction pipe Due to the following reasons, it can be widely used in large diameter steel tube production:

1) As long as the change of forming angle, you can use the same width of the strip steel production of various caliber steel tube;

2)Because it is a continuous bending pipe, so the scale length is not limited;

3)Weld spiral is evenly distributed in the whole pipe circumference, so the size precision and strength of steel pipe are high;

4)Equipment cost is cheap and it is easy to change the size, suitable for the production of small batch and many varieties of steel pipe. Spiral pipe weld seam length ratio, such as the length of L, the weld length is L/cos (θ). While the majority of defects in steel pipe weld and heat affected zone in the weld length, means that the probability of failure, which is a major cause of long-term constraints and more extensive application of the spiral welded pipe, spiral is long debated the pipe and pipe joints, especially compared with UOE steel who better problem. Spiral pipe manufacturing technology development to today, we should correctly assess and comprehensively,, to understand the problem of long spiral pipe seam. First of all, because of the defect and the weld are parallel, so the spiral tube, the weld defect is "inclined defects". In the process of using, the principal stress direction of steel pipe, oil and gas pipeline namely equivalent defect length of the steel tube axis direction is smaller than the straight pipe; secondly, because of pipeline steel are rolled steel, the impact toughness have larger anisotropy along the rolling direction, the CVN value can be 3 times higher than the vertical to the rolling direction CVN. The principal stress is perpendicular to the direction of minimum tube shock resistance ability of the straight pipe and spiral pipe is staggered tube shock resistance ability of the lowest direction, making the spiral tube weld length weakness change into advantage.

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