Grooving corrosion of seam welded oil pipelines

(in lingua inglese)

Failure of the pipeline segment is directly related to a poor quality ERW process, since incomplete penetration, un-melted zones, and lack of fusion close to the pipe inner surface were present on extended regions along the seam weld line. Grooving corrosion is largely accelerated by the above-mentioned welding defects, leading to rapid thinning in these defective regions of the seam weld. At a critical wall thickness, the radial stress of the flowing fluid exceeds the pipe hoop strength leading to crack initiation and propagation until stress relief is attained.