Bathroom brake circuits with vermicular graphite

Abstract

The processes of structuring in cast iron of different chemical composition in the range of cooling rates of 0.5 ... 5.5 deg / s, which take place in the roll casting mould, are investigated. Scientifically based theoretical and experimental results were obtained, the set of which allowed to develop highly effective technologies of casting of rolling rolls from cast iron with vermicular graphite with increased operational characteristics. Optimum content of rare earth metal (REM) in roller cast iron with vermicular graphite at different cooling rates was experimentally established. In the low sulfur (up to 0,03%) cast iron, the rare earth metal residual (REMres) content is -0,065 ... 0,176 (for a cooling rate of 0,5 deg / s) and 0,01 ... 0,156% (for a cooling rate of 5,5 deg / s) . In the cast iron with high sulfur content (up to 0.10%), at the cooling rates studied, the intervals of concentrations of REMres have been experimentally established to provide the vermicular inclusions of graphite: at a cooling rate of 5.5 deg / c - 0.081-0.129%, and at a speed of 0.5 deg / s - 0.161 ... 0.190%. When modifying melts with a complex modifier based on magnesium KMg9, the Mg content at cooling rates of 5.5 and 0.5 deg / s should be within 0.022 ... 0.03 and 0.019 ... 0.03%, respectively, when treated with the complex KMg9 and FS30RZM30 in the cast iron it is necessary to have 0,0071 ... 0,015% Mg and 0,023 ... 0,025% REMres. With such content of modifiers, the best combinations of microstructure and physical and mechanical properties of castings are obtained. The areas of formation of vermicular graphite inclusions in roll cast irons were determined when processed with a complex modifier based on rare-earth metals and ferrotitanium: at a cooling rate of 5.5 degrees / s and a titanium content of 0.40 ... 0.42%, the concentration range of the rare-earth bridge for stable production of graphite inclusions of vermicular form has expanded and was 0.061 ... 0.169%, and at a cooling rate of 0.5 deg / s –0.129 ... 0.230%. The technological process of casting of bleached roller rolls has been improved due to the application of a highly effective complex modifier (ligature) of optimal composition for the modification of the base metal. The technology for the production of pig iron with vermicular graphite is developed and mastered at casting of rollers with the use of mixtures for modification consisting of two ligatures in the ratio of 1: 3.