Navoi State Mining Institute, Navoi, Uzbekistan:

A. A. Zhumaev, Dr. Phil., Associate Professor, Dept. of Engineering Technology, e-mail: ahmadjon_jumayev@mail.ru

Kh. I. Akhmedov, Cand. Eng., Associate Professor, Head of the Dept. of Engineering Technology

Belarusian National Technical University, Minsk, Belarus:
K. E. Baranovsky, Cand. Eng., Associate Professor, Dept. of Metallurgy of Ferrous and Non-Ferrous Alloys

Tashkent State Transport University, Tashkent, Uzbekistan:

Yu. N. Mansurov, Dr. Eng., Professor, Dept. of Materials Science and Mechanical Engineering

The article considers white wear-resistant chrome cast iron used for making castings used in the mining industry, in particular, for parts of centrifugal grinders. Parts are made at the Navoi Machine-Building Plant (Uzbekistan). The white wear-resistant cast irons 280CrNi29 1, 300CrNiMoTi32 2 2 and experimental cast iron 330Cr17 used at the plant were studied. To conduct research on the above-mentioned cast irons, «Feeding disk» parts with a diameter of 380 mm, a thickness of 38 mm, and a weight of 35 kg were cast into earthen molds. The microstructure in the cast state of all the studied cast irons is a trostiteaustenitic metal matrix with eutectic colonies. The content of carbides in pre — eutectic cast iron 280CrNi29 1 was 30–32%, the hardness on the surface of castings 50–51 HRC, and in the center 45–46 HRC, the amount of carbides in cast iron 300CrNiMoTi32 2 2 was 35–37%, the hardness on the surface of castings 56–57 HRC, and in the center 52–53 HRC, the amount of carbides in eutectic cast iron 330Cr17 was 39–40%, the hardness on the surface of castings 53–54 HRC, and in the center 50–51 HRC. The cost of the 330Cr17 alloy is 1.3 times lower than the cost of the 280CrNi29 1 alloy, and 4.5 times lower than the cost of the 300CrNiMoTi32 2 2. To obtain parts from a cheap alloy 330Cr17, a technology for manufacturing castings using metal refrigerators is proposed, in this case, the hardness of castings from the alloy 330Cr17 is 58–61 NRC on the surface and 55–56 HRC in the center of the castings. The size of carbides is reduced by 3–4 times. By obtaining a directional structure and grinding carbides during casting using metal refrigerators, the wear resistance of cast parts increases by at least 20%. In this case, you can use cheaper grades of chromium cast iron, containing less alloying.

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