THERMAL FACTORS AND INTEGRATED APPROACHES TO THE PROTECTION OF MOLDS DURING CASTING OF PIG IRON AND FEROALLOYS
Purpose. Obtaining a finely dispersed pearlite structure of casting, which makes it possible to increase the operational stability of ingot molds.
Methods. In research, an integrated approach was used to protect molds with a specially developed non-stick coating - fabrication of molds from ordinary grades of cast iron modified with nitrogen-containing components. A method for calculating the thermal conductivity of a multilayer wall made it possible to determine the optimal thickness of a casting in its critical sections.
Results. The introduction of an integrated approach to the production of castings from cast iron modified with nitrogen-containing components with the combined use of the non-stick coating LP-1 will increase the service life of molds at fairly low extra costs for their production and protection during casting. Based on the thermal calculations of the thermal conductivity, it should be underlined that the 2 times lower consumption rate of non-stick material LP-1, compared to lime suspension, is possible due to the reduction of the layer thickness.
Originality. On the basis of the theoretical justification of thermal processes during thermal operation of molds with various non-stick coatings and experimental data, an increase in the operational stability of products is achieved.
Practical implications. The operation of molds made from ordinary cast iron is characterized by low durability, which results in downtime of a casting machine for their replacement. Therefore, the increase in durability of products will improve the manufacturability of the process and reduce the cost of production. This is consistent with the data obtained and the decrease in the thermal conductivity of the non-stick coating in order to reduce the thermal shock on the inner surface of the product, and, as a result, to reduce the formation of microcracks in molds. The integrated approach allows to significantly increase the service life of a mold through the use of heat-resistant non-stick coatings. Increasing the durability of a casting container leads to the production of cast products with improved mechanical properties at high temperatures, which can be achieved by modifying ordinary cast iron with nitrogen and titanium.
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