Optimization of the composition and structure of wear-resistant white cast irons used in the mining industry

Abstract

The mining industry of Uzbekistan uses hundreds of tons of white wear-resistant cast iron monthly for the manufacture of parts for machinery and equipment that extract natural raw materials. Only the Production Association Navoi Machine-Building Plant (PO «NMZ») monthly produces cast parts from wear-resistant high-chromium alloyed white cast iron with a volume of more than 120 tons per month. Most of the parts are made for rock crushers; their wear during work in mines shortens the service life of machinery and equipment. Parts of foreign equipment: dredge pumps, lining of grinding mills, hydraulic transport and others are made of white cast iron, highly alloyed with chromium, nickel, copper, titanium and other chemical elements. The annual import into the republic of parts made of cast irons of complex chemical composition requires signifi cant costs. In order to save money by refusing to import parts, a domestic wear-resistant white cast iron of grade 280Kh29NL was developed, from which rubbing parts, operating under wear conditions in mines, for mining equipment are cast in the foundry of the Navoi Machine-Building Plant. Considering that ferroalloys for the production of cast iron are also imported, the cost savings in the production of mining equipment parts instead of worn-out ones is insignificant. The purpose of this work is to optimize the composition of highly alloyed wear-resistant white cast iron for its replacement in industry with an economically alloyed analogue, as well as to improve the structure of the composition-optimized white wear-resistant cast iron to obtain the required level of performance properties of parts operating under friction and wear conditions. For this, phase transformations, the structure and properties of white cast iron, and the conditions for casting parts were studied. Based on the research results, recommendations were developed for economical alloying and casting technology for friction and wear parts.