The study presents the results of laboratory testing of the phenomenon of cracking in the process of cross rolling. A new method of determining the critical value of the damage function was developed, in which a disc-shaped sample is subjected to rotational compression in a channel. In this method the Mannesmann effect was used. The laboratory tests were conducted for C45, 50HS and R260 grade steel in the temperature range 950°C-1150°C. In order to research various methods of simulating the phenomenon of cracking in the process of cross rolling, physical modelling was also employed. The model material was commercial plasticine, cooled to the temperature 0°C-20°C. Comparing the test results for both the real and model material allowed one to determine the range of the forming temperature for the model material, in which the cracking process is similar to the case of the real material.

The article considers the method of obtaining reinforced castings from gray cast iron by lost foam casting. The aim of this study was to determine the microstructure formation of gray cast iron reinforced with inserts of carbon and stainless steel in this casting method. The results of the research have shown that the products of destruction of expanded polystyrene have a positive effect on the bonding formation of cast iron with reinforcing inserts. When steel wire is used as reinforcement, a decarbonized layer of cast iron is being formed around it, in which the inclusions of graphite are smaller and their quantity is less than in the main metal. Due to carburization, the surface structure of the reinforcement changes from ferrite to pearlite with cementite. Steel wire reinforcement can be effective in increasing strength and toughness of gray cast iron. The usage of stainless steel reinforcement leads to the formation of a transition layer on the part of the matrix metal. It contains ledeburite with dissolved chromium, which increase the wear resistance of cast iron.