Production of rubber and plastics is based on mixing the components and producing several types of rubber and plastic foil. These processes take place in mixing mills and calenders. Mounted rolls must have very high wear resistance of the working layer when in contact with highly abrasive materials. Therefore, the working layer is made of hard cast iron - a high percentage of cementite in the pearlitic matrix ensures high hardness values and absolute graphite absence. High quality nodular iron for cores and necks of rolls should assure high values of tensile strength despite the drilling of the central borehole, peripheral and connecting holes. The rolls are namely constructed in a way, that the quality of the rubber and plastics can be reached with bending.
Former static double layer casting has been replaced by centrifugal casting. By preparing a quality melt, a higher level of homogeneity and joining of the layer and core can be achieved. Moreover, a quality warmth transfers of the heating-cooling liquids which maintains a steady working layer temperature, is guaranteed.
The quality of both cast iron types needs to reach the highly set standards for heat treatment - as in working layer as well as on the bearing surfaces.