Using the same width of the strip to produce a steel pipe of different diameters. In particular used to produce large-diameter steel pipe oct. Spiral seam is exposed to stress than a straight seam is small, only 75-90% Longitudinal therefore able to withstand greater pressure to pay. Longitudinal compared with the same diameter, wall thickness can be reduced 10-25% from the mechanical point of view, a thin-walled circular tube (such as pipelines), when subjected to pressure in its radial stress & c is the axis stress & l (see Equation 15-4.5.) twice. Thus, when the radial stress is a decisive factor determining the wall thickness. Spiral longitudinal weld on a straight line tangent to the cylinder tube surface (ie parallel lines on the surface of the cylindrical body axis) forms an angle between a, is called molding angle. Size tip Indeed, the general diameter tolerance of not more than 0.12% less than 1/2000 oval deflection less than 1%, generally eliminates the need for sizing and Johnson straight processes. Continuous production: in theory, can produce no infinitely long pipe, cutting head, a small cut tail loss, can improve the utilization factor of 6 to 8% metal flexible operation, easy to adjust the replacement of species (and Longitudinal comparison). Equipment light weight, low initial investment, some units made mobile, can be produced directly on the construction site of the laying of the pipeline. New Chinese extubation sales: http: //www.xzhbgc.com Hebei sales extubation manufacturers: http: //www.xzhbgc.com/ProductList.asp