The paper presents the problem which concerning the technology of bimetallic castings in materials configuration: high-chromium steel as the working layer and grey cast iron as the base part. The aim of the studies was integrate the process of manufacturing of bimetallic casting with the heat treatment of hardening type of X46Cr13 steel insert by applying the mould with sandmix on a matrix of chromite sand. Range of studies included the chemical composition analysis, non-destructive ultrasonic tests to examine the quality of the permanent bond between the working layer (steel insert) and the base part (grey cast iron) of the bimetallic castings, hardness measurements as well as metallographic examinations performed on the optical and scanning electron microscopes. On the basis of obtained results was concluded that the self-hardening process occurred in the X46Cr 13 steel working layer and in result of this the hardness on its surface equalled approx. 45HRC in case of the bimetallic castings with full permanent bond between both parts.