25 years field test history and fatigue damage analysis for a scrapped ladle crane

Abstract

Fatigue performances of ladle cranes will gradually decrease with the increase of service years. The service history and the fatigue damage of a scrapped ladle crane were investigated and analyzed in this paper. The test history of the ladle crane was collected and concluded, and the statistical parameters of lifting capacity and the crack condition during service were determined. The last comprehensive field test before scrapping the ladle crane was introduced in detail and the damage evolution was analyzed. The geometry measurement showed that the main girders’ stiffness had changed obviously. The stress test of the crack-prone positions of the metal structure revealed their remaining bearing capacity and the damage evolution characteristics. Further analysis proved that the static stiffness of the main girder has a closer relationship with damage deterioration. Some material property inspections were carried out for samples cut from the scrapped crane’s main girder, which were of the load-carrying part and the non-load-carrying part respectively. Results showed that the elastic modulus and hardness of the materials decreased evidently after service, while other mechanical properties did not change significantly. This study will provide useful references for further understanding of the fatigue characteristics and evolution behaviors of ladle cranes.