Corrosion damage and periodic inspections on pressure devices and lifting equipments

Abstract

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.