Corrosion damage and periodic inspections on pressure devices and lifting equipments

This paper deals with requirements for service safety conditions of pressure devices and lifting equipments, according to the European and Italian Standards. Periodic controls and inspections are necessary to check corrosion damage and determine residual life, as showed for some significant case histories. As concern as pressure device, hydrogen induced cracking phenomena in steel walls of a demister, utilized to enhance the liquid droplets removal in a vapor stream, were detected by ultrasound measurements. The measured defect sizes were put in comparison with the required limits to verify if this device can be maintained in service. About lifting equipments, two different corrosion mechanisms were examined by detecting defects and measuring residual plate thickness: crevice, due to aggressive environment, at the interstitial of steel plates overlap in a welded and bolted joint of a gantry crane; lastly, crevice and corrosion fatigue of steel rail and plate in a double girder shipyard bridge crane, that was exposed for some decades to the daily aggressive action of direct solar radiation and sea salt, detrimental for the coating layer. In these two cases both defects size and plates thickness were considered with the aim of indicating treatments and restoration procedures of damaged components.