OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 24 No. 4 2022 a b Fig. 2. Effect of molybdenum concentration in SChKM-45 gray cast iron containing 0.52 wt.% of nickel and 0.38 wt.% of vanadium: a – on hardness; b – on ultimate strength a b Fig. 3. Effect of vanadium concentration in SChKM-45 gray cast iron containing 0.6 wt.% of molybdenum and 0.55 wt.% of nickel: a – on hardness; b – on ultimate strength The result of the experiments to determine the optimal chemical composition for an alloy with a complex of high properties is the development of gray cast iron grade SChKM-45 alloyed with nickel, molybdenum and vanadium. The authorship of the development is entrenched by the RF patent for the invention No. 2733940 [13]. The chemical composition of alloys SCh35, ChMN-35M and SCHKM-45 is presented in Table 1. Mechanical properties of SChKM-45 cast iron compared to basic SCh35 cast iron and developed earlier ChMN-35M cast iron are presented in Table 2. The properties of alloyed gray cast irons are largely determined by the structure of its metal matrix, the shape and distribution of graphite inclusions. Comparative analysis results of the structure of cast irons analyzed in this work are presented in Table 3 [11]. Ta b l e 1 Chemical composition of SCh35, ChMN-35M and SChKM-45 cast irons Cast iron grade Mass fraction of elements, % Fe – balance С Si Mn Мо Ni V Cr Cu S P SCh35 2.92 1.45 0.88 – – – 0.04 0.03 0.04 0.01 ChMN-35M 2.85 1.39 0.86 0.82 0.75 – 0.05 0.03 0.03 0.02 SChKM-45 2.65 1.35 0.89 0.45 0.52 0.34 0.05 0.03 0.03 0.02
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