The effect of extreme deformation conditions on the impact toughness of the exploited steel of the gantry crane

Operation of portal cranes causes a loss of initial mechanical properties of the steels of the main retaining structural elements. Therefore, the operational degradation of crane steel considering the influence of extreme metal deformation rates on the brittle fracture resistance, caused by the impact load of structural elements, is assessed. The impact toughness of the Charpy specimens cut longitudinally and transversally relative to the rolling direction of the sheet material is determined. Two metal states are compared: operational degraded and subjected to an additional high-speed deformation by impact loading. A significant decrease in the brittle fracture resistance of specimens cut out from the areas near high-speed metal deformation is found.