In-Service Brittle Fracture Resistance Degradation of Steel in a Ship-to-Shore Portal Crane

Abstract

The assemblies of a ship-to-shore portal crane after 33 years of service were studied on the possible loss of the initial brittle fracture resistance level by rolled steel sheets. Strain gauge measurements were used to predict the level of operating stresses. The latter and a decrease in the Charpy impact strength were established to be distinctly related. Transverse specimens are shown to generally exhibit a lower impact strength level as compared to that of the longitudinal ones. The differences in the brittle fracture resistance of specimens, differently oriented with respect to the stamping direction, are revealed to be growing with the metal degradation level. This level along the stamped fibers is demonstrated to increase with a decrease in the sheet thickness, which can be explained by the effect of aggressive marine environment as a factor of metal hydrogenation.