Raziskave lastnosti in obdelovalnosti ulitkov iz visokolegirane kromove litine za dele turbinskega polnilnika (Slovene)

Company Cimos from Koper manufacturing cylindrical discs for Turbocharging systems. The company buys thick-walled tubes aboard and manufactures final products from them with various machining and cutting procedures. Bush is casted of high-alloyed, high-carbon chromium cast-iron. Microstructure and mechanical properties of the cromium cast-iron are the cause of poor machinability and cutting performance. The main difficulties are high wear of the cutting tools and the integrity of the products surface. Damages often occur on the machined pieces wich point to the considerable brittleness of cast-iron and the need to define precisely the conditions of mechanical machining and the selection of tools.The problems of cutting stem on one hand from the material the machined pieces are made of and from the technology of cutting on the other hand. The solution of the difficulties arising from the first problem lies in precise characterization of microstructure and phase compozition of alloy and morphology, distribution and fraction of various microstructure constituents.The solution of the second problem is proper selection of tools and the optimization of the cutting conditions.