Large-diameter spiral steel pipe is that spiral pipe that use steel strip coil as raw material, often warm extrusion molding, two-wire double-sided submerged arc welding(dsaw) process automatically welded, raw material is strip volume, wire, flux. The input to go through need rigorous physical and chemical testing. Strip head and tail docking, using a single wire or twin-wire submerged arc welding and automatic submerged arc welding rolled into the steel pipe. Prior to molding, strip is through flattening, cutting, trimming, edge planing, transportation and to the curved side surface cleaning. Electric contact pressure gauge to control the conveyor on both sides of pressing cylinder pressure to ensure the smooth delivery of the strip. The external control or internal control roll forming. Weld gap control device to meet the welding requirements ensure that the weld gap, diameter; misalignment and weld gap have been strictly controlled. Within the weld and outside welding Lincoln welding machine, a single wire or twin-wire submerged arc welding, the stability of the welding specifications. Welding finished weld line ultrasonic injury examination was to ensure 100% of the spiral weld nondestructive testing coverage.
Wrong side of reasons large diameter spiral pipe: when the large-diameter spiral steel pipe production, the wrong side often occur; its impact are many factors, in the practical production, it often leave the steel pipe from dry wrong side of the ultra-poor downgrade. Analysis of large diameter spiral pipe the wrong side of the causes and preventive measures necessary.
1,the camber of the strip caused by the steel tube wrong side of the main factors. The forming of the spiral welded pipe, strip camber will continue to change the forming angle, resulting in changes in the weld gap, resulting in open seam, even taking the wrong side of side. A serious impact on the quality of the steel tube so observing the camber of the unwinding of the steel strip coils, by controlling the vertical roll so that disc to cut the continuous removal of part of the camber and forming angle control and correction is in the production process to reduce strip camber effective way to produce the wrong side.
2,due to the shape and size of less accuracy without trimming the strip head and tail docking could easily lead to strip hard bend caused by the wrong side.
3,the strip head and tail docking welding the weld metal when overmolding if not handled properly likely to cause the larger the wrong side.
4,the poor condition of strip edge is another important reason causing the wrong side.
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Post time: Dec-31-2019