The Influence of the Cooler Material on the Structure and Hardeness Gradient of a Grey Pearlitic Cast Iron

Abstract

The structure and properties of grey cast iron castings are considerably influenced by the cooling rate during solidification. In order to obtain grey cast iron parts with a hard superficial layer (wear resistant), external metallic coolers are placed on those surfaces during casting. This is the case of cam pushers, camshafts, driving shafts, metalworking rolls, etc. Cast iron coolers or steel coolers are mostly used in practice. The cooling rate during solidification is influenced by the thermo-physical characteristics of the coolers. This paper presents the results obtained by simulation and experimental research on coolers material influence on the structure and hardness of the surface layer of a pearlitic cast iron sample. It was studied the solidification of samples with dimensions 20 x 20 x 60 mm, cast of pearlitic cast iron in six variants: without a cooler and in the presence of some metallic coolers of different thermo-physical characteristics (iron, steel, copper, titanium and aluminum coated with a thin layer of steel). It was studied the influence of cooler material on structure of the superficial layer, on thickness of the hardened layer, on superficial hardness, on the temperature field and cooling rates. Conclusions are drawn regarding these influences and the possibility of using external coolers in industrial practice.