Welding a pressure vessel is where skill meets regulations. PED does not tell you how to weld – it tells you how to prove your welding is safe. That proof starts with two qualifications: the Welding Procedure Qualification and the welder‘s own performance qualification.
For a typical longitudinal seam, the manufacturer prepares test plates welded under exactly the same conditions as the real vessel. Those plates are cut into tensile and bend specimens and pulled apart in a test machine. If the results meet the material’s standard, the procedure is approved. Each welder then repeats the test – welding a coupon that is radiographed or bend‑tested. Their certificate is valid only for the positions and processes they passed.
During production, every weld seam in a PED vessel gets an identity: it is marked or mapped in a drawing. For vessels in higher categories, a Notified Body must witness some of the welding and review the records. The welder‘s name, the procedure number, and the inspection results all go into the technical file. The welding itself may look ordinary – a torch moving along a seam – but the invisible structure of qualifications and traceability is what makes it PED‑compliant.
Post time: May-25-2026