General corrosion damage can significantly reduce the collapse resistance of externally loaded pressure vessels. This is a consequence of the loss of wall thickness and the associated development of high bending and membrane stresses in the corroded area. A common method used to recover wall thickness is weld buttering, whereby weld material is applied to the affected area. This method is convenient and cost-effective compared to other repair options; however, the extent to which weld-induced distortions and residual stresses counteract the reclamation of wall thickness has not been studied. In the current work, the influence of weld buttering on collapse resistance was explored through collapse tests. Three ring-stiffened cylinders were fabricated by cold rolling and welding high-strength steel plates. Corrosion damage was simulated in two of the cylinders by removing approximately 20% of the wall thickness in a square patch extending between two ring-stiffeners. The simulated damage on one cylinder was repaired using weld buttering. A third baseline cylinder had no simulated corrosion damage. With respect to the baseline cylinder, the simulated corrosion damage reduced the collapse capacity by 5.9%; weld buttering recovered 4.8% of that capacity. It is concluded that weld buttering can be an effective corrosion repair technique, despite the introduction of weld distortions and residual stresses in the vessel.
Author: Swanek, Doug S., MacKay, John R., Farrell, Shannon P., Link, Rick and Timms, Chris M. J.
Publisher: ASME 2013 Pressure Vessels and Piping Conference, Paris, France, July 14-18
Purchase Link: American Society of Mechanical Engineers