CS vs LS Joint

Circumferential weld always done before Longitudinal weld? Please Explain


LS must be done NDT before assembly the CS joint.

Follow sequence fabrication:

  • Easy assembly, fitting-up, weld, and alignment.
  • Easy repair weld joint (if failure)

NDT and acceptance criteria:

  • Random or spot RT: T junction joints are normally selected 100% RT at last 300mm.
  • Almost weld imperfections or defects found at T junction.


C seam weld always carried out in the last stage of fabrication. It will aid inspection and NDT

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