Fracture of a 1055 Steel Crane-Bridge Wheel

A bridge wheel on a crane, forged from 1055 steel, fractured after one year of service. The wheel fractured in the web between the hub and the rim. A small area containing beach marks that originated in a heavily burned area on the web surface was revealed by visual examination of the fracture surface. Surface burning to a depth of approximately 0.8 mm was disclosed by metallographic examination of a section taken through the region that contained the beach marks. A forging defect was indicated by the degree of decarburization and oxide dispersion that were visible. The failure was concluded to have been caused by surface burning during the forging operation. As a preventive measure more closely controlled heating practice during forging to eliminate surface burning was recommended. The burnt region was suggested to be removed in case burning occurs.