OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 1 2024 only in combination with spherical or fl ake graphite. In contrast, V ASTM form is an actual microscopic image of degenerated graphite, which has a very diff erent appearance II ISO from. Although VI ASTM form shows an example of blasted graphite, EN ISO 945-1 does not provide reference pictures for these types of graphite degeneration. Both ASTM A247 and EN ISO 945-1 represent fl ake graphite (I ISO and VII ASTM) in the same way. In addition to stylistic illustrations, EN ISO 945-1 also contains actual microscopic examples of I ISO Forms and III–VI ISO. In GOST 3443-87, fl ake graphite is represented by Гф1–Гф4, vermicular Гф5, Гф6. According to the requirements of GOST 3443-77, during the analysis process, in the case of a pronounced mixed morphology of graphite, it is necessary to carry out a manual analysis of each structural component (lamellar, vermicular, spherical), which is associated with high labor intensity of the analysis and subjective interpretation of the results. In GOST 3443-87, lamellar graphite is represented by Гф1–Гф4, vermicular Гф5, Гф6. According to the requirements of GOST 3443-87, during the analysis process, in the case of a pronounced mixed morphology of graphite, it is necessary to carry out a manual analysis of each structural component (lamellar, vermicular, spherical), which is associated with high labor intensity of the analysis and subjective interpretation of the results. In [35–38], a new approach to the instrumental assessment of the morphological features of graphite during crystallization is presented based on thermal analysis combined with an assessment of expansion and contraction during cooling. Amechanical expansion/contraction system was used to evaluate the initial expansion of magnesium-treated cast irons, which was identifi ed as the main factor infl uencing the shrinkage sensitivity of cast irons with diff erent graphite morphologies [36]. It was found (fi gure 6) [39] that the formation of graphite led to an important event at the onset of solidifi cation, namely initial expansion in all cast irons containing graphite, due to the force generated by the formation of diff erent graphite morpholoFig. 6. The cooling curve of pre-eutectic cast iron with characteristic temperatures showing the solidifi cation intervals of the primary and eutectic phases and the correlation with the formation of shrinkage defects [39]
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