COMPARATIVE STUDIES OF EFFECTIVENESS DOMESTIC MODIFIERS OF 20GL STEEL OF CASTING ON GASIFIED MODELS

HRUMLS

Abstract

The work is devoted to the urgent problem of increasing the strength of cast low-carbon and low-alloy steel 20GL due to the use of modifiers used in steel smelting. The change in mechanical properties was achieved by furnace and out-furnace treatment of the steel melt with various domestic complex modifiers and subsequent heat treatment according to the selected maintenance regime. The samples for comparative tests were obtained using gasified model casting (LGM) technology. The main mechanical properties were determined at normal temperature, and the values for impact bending on samples with a U-shaped incision were determined at minus 60 °C. Studies have shown a significant difference in the properties of 20GL steel, depending on the modifier used. The use of the MKksk 19 complex modifier makes it possible to increase the continuity of the casting, reduce the number and size of non-metallic inclusions, and generally obtain a uniform structure over the entire cross-section of the sample (casting). The impact strength of KCU-60 for all samples during the tests was 1.7-2.6 times higher than the values specified in GOST 977-88, GOST 21357-87 and GOST 22703-2012. However, the presence of Widmannstatt samples in the structure indicates the need to find the most optimal maintenance regime.