Dimensional deviation is mainly manifested in straightness, roundness and uneven thickness of SSAW steel pipe.


In most cases, the straightness tolerance of spiral pipe is large, but if the manufacturing standard of spiral pipe straightness exceeds the predetermined value, it will constitute the reason for return. Therefore, attention should be paid to the spiral pipe factory.
Roundness tolerance will affect the use of spiral steel pipe, mainly on the wrong side of the weld joint. Roundness tolerance leads to the wrong side of welded joints, which not only reduces the pressure capacity, but also reduces the stress concentration. When the site group, roundness of some pipes can be corrected. The outer diameter deviation and its influence on the spiral steel pipe are equivalent to the roundness tolerance used.


Uneven wall thickness is often neglected, and many spiral steel tube standards are not clearly defined. If the wall thickness is not uniform, the results will not only be set to the wrong side of the joint, but also have a negative impact on secondary deformation processing (such as steel pipe manufacturing).