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One of the spiral pipe (SSAW steel pipe) testing methods is to carry out a water pressure test, so what is the purpose of the water pressure test? Here is a brief introduction.
The hydraulic test of the spiral steel pipe during the construction is a comprehensive inspection of the quality of the pipe, the joint, and the construction I. It is also an indispensable key test item before the project acceptance.
Calculation formula of hydrostatic test pressure of spiral steel pipe:
(P: test pressure of hydrostatic test, unit (Mpa); S: test stress of hydrostatic test, unit (Mpa); T: nominal wall thickness of steel pipe, unit (mm); D: nominal outer diameter of steel pipe, unit (m)), the calculation result is accurate to 0.1Mpa.
The SY/T 5037-2012 standard stipulates: For spiral steel pipes with a nominal outer diameter of less than 508mm, the hydrostatic test pressure retention time is not less than 5s, for spiral steel pipes with a nominal outer diameter of not less than 508mm, the hydrostatic test The pressure holding time is not less than 10s.
The GB/T 9711-2011 standard stipulates: For spiral steel pipes with a nominal outer diameter of less than 457mm, the hydrostatic test pressure retention time is not less than 5s, for spiral steel pipes with a nominal outer diameter of not less than 457mm, the hydrostatic test The pressure holding time is not less than 10s.
Spiral welded pipe hydrostatic test is to test whether the steel pipe meets the design requirements at the specified pressure by filling, pressurizing, and maintaining pressure into the test steel pipe. It is the most intuitive and closest testing method to the actual use of the steel pipe. The inspection standard clearly requires that each spiral welded pipe be subjected to a hydrostatic pressure test, mainly to check that the seam or the pipe body is not damaged or leaked under the specified level of pressure.
While the hydrostatic test inspects the quality of the steel pipe itself, the test steel pipe will undergo certain elastoplastic deformation under the superposition of hydrostatic pressure load and inherent residual stress, which will affect the external dimensions, mechanical properties, and residual stress distribution of the steel pipe. The quality of these three aspects is closely related to the safety of pipeline operation. Therefore, it is of great significance to study the influence of hydrostatic pressure test on the external dimensions, mechanical properties, and residual stress distribution of spiral welded pipes.
