The ellipticity of spiral steel pipe in the production process is inevitable, but the ellipticity can be reduced, if the ellipticity is large, in the construction will bring great trouble. Ellipticity is a spiral steel pipe in the forming process due to the low precision of the equipment, resulting in the wrong side of the strip in the rolling process, which requires debugging equipment in order to completely close the weld seam, the process of closing will present the diameter of the pipe wobble, which is generally referred to as ellipticity.
 
    Control ellipticity we need to start from the above aspects, in order to better cooperate with the construction, list *, the selection of raw materials, choose a large steel mill raw materials, generally uniform plate edge, wall thickness, the second, production standards, must use the national standard specifications, the national standard in the skills required for ellipticity than the Ministry of high standard. From the above two points can strictly control the ellipticity.
 
    Spiral steel pipe in the domestic industry specification is basically two, one is the Ministry of Petroleum norms, SY/T5037 series, this specification is cited in the former Soviet Union  norms, on the construction of today's specifications are too low, now the general manufacturers do not choose this specification, the other is the specification, that is, GB/T9711, series,  from 1997 on the announcement of this specification, after improving the current series is GB The other is the specification, which is GB/T9711,series, published from 1997, and after improvement, the current series is GB/T9711.1-2011 and GB/T9711.2-2011.
 
    This specification on ** small, medium and large projects can be used, the quality is guaranteed. Overseas import and export trade friends know that there is an API series, API also has two series, API PSL1 equivalent to the domestic 9711.1, API PSL2 equivalent to the domestic 9711.2, some friends said the domestic and foreign which specification is high? In practice, foreign norms are higher, due to the introduction of domestic spiral steel pipe production line is, many developed ** now fast screening such production skills.