Large diameter spiral pipe blasting, because the welds suffered the normal stress and the resultant stress is relatively small, blasting mouth generally not originated in the spiral weld its security than longitudinally welded pipes.
But regardless of yield pressure is still bursting pressure are lower than the straight seam welded pipe. Test marked according to research institutions In the United States, spiral welded pipe and Longitudinal course, with a level of spiral welded pipe with high impact toughness.
Strength characteristics: the delineation of the submerged arc welding process, each weld shall have the arc at the arc quenching at each longitudinally welded pipes welded girth, unable to reach the premise. There may be more of welding defects at the arc extinction . Tube in the inner pressure, usually two main stress on the tube wall, i.e., the radial stress 6 and axial stress 5. Followed by the increase of steel pipe diameter, the steel grade progress, the greater the trend of steady expansion of ductile fracture tip. Hydrostatic burst strength: since the radial stress is present in the maximum stress on the large diameter spiral pipe, weld in this direction of the vertical stress to withstand the maximum load. Measurement results, spiral welded pipe fatigue strength seamless and electric resistance welded tube test data and seamless distribution and resistance tube in a unified area, while higher than the submerged arc longitudinally welded pipes. Pipelines because lose changes in the amount of actual control process, the steel pipe to accept the role of random alternating load. Low transmigration fatigue strength of the solution the steel pipe to having a significance to determine the life of the pipeline. The same work under pressure, unified diameter spiral welded pipe straight sesm welded pipe wall thickness can be reduced. The pipeline development trend of large-diameter, high-strength.
Toughness and fatigue strength: the relevant comparison test and verify large diameter spiral steel pipe and Longitudinal yield pressure and burst pressure measured and theoretical values consistent deviation close.
When the large diameter spiral steel pipe weld defects corresponding parallel exists, its extended risk is also smaller because of the smaller spiral weld force. This has proved superior to plastic deformation capacity of spiral welded longitudinally welded pipes, blasting mouth is generally confined to a pitch, which is the extension of spiral welded seam rip from the strong constraint due.
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Post time: Nov-24-2020