Thermal Fatigue Material Degradation of Caster Rolls' Surface Layers

Degradation of surface layers of continuous caster rolls under service conditions is studied. The roll material is steel 25 Kh1M1F. A statistical analysis of size, orientation and distribution of surface cracks is carried out. Microhardness measurements are performed and structural degradation of the material surface layers is evaluated as a function of the distance to the roll surface. It is found that the damage of the surface layers, estimated by means of a homogeneity coefficient, is 60–72% greater than the damage at the depth h = 9–32 mm. The evolution of the roll material microstructure under tensile deformation is studied as well.