Özet:

The object of study in this work is cast iron with lamellar graphite, modified with two types of modifiers – FeSi75 and FeSi40V7. In this work, the influence of vanadium on the mechanical properties of cast iron used for castings for engineering purposes was determined. The existing problem lies in the fact that ignorance of the influence of the alloying element on the mechanical properties of the alloy does not allow determining its consumption rates during the melting process. This can lead to unnecessary costs for materials for melting and casting, and not be justified in terms of the expected improvement in properties. To determine the effect of vanadium on properties, three indicators of the quality of cast iron are considered: tensile strength, stiffness, and a generalized quality index for mechanical properties. A decision is proposed on the procedure for checking the significance of the influence of vanadium within the considered range of variation V=0.04–0.078 % on these indicators. It has been established that the introduction of vanadium into cast iron as part of the FeSi40V7 modifier leads to a decrease in the tensile strength by 4 %, but to an increase in rigidity by 2 %. A significant influence of vanadium with a probability of 95 % was also established with respect to the generalized quality indicator for mechanical properties – the introduction of vanadium contributes to a drop in this indicator by about 5 %. As a result, it was concluded that the use of vanadium in the composition of FeSi40V7 within the final content in cast iron at the level of 0.04–0.078 % can be expedient only if it is necessary to increase the hardness of cast iron due to the promotion of carbide formation during alloy crystallization. The presented study will be useful for machine-building enterprises that have foundries in their structure, where cast iron is smelted for the manufacture of castings. Author Biographies Liliia Frolova, National Technical University «Kharkiv Polytechnic Institute»; PC TECHNOLOGY CENTER Postgraduate Student Department of Foundry Production; Researcher Scientific department

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