Oskolsky Electrometallurgical Combine of Metalloinvest has started production of Ac500C class rebar products with diameters from 12 to 40 mm. It is designed for the production of reinforced concrete structures that operate at extremely low temperatures and high seismic loads.
Photo: "Metalloinvest".
The new products have been developed taking into account the requirements for facilities being built in the Far North, for which high metal ductility, stability of mechanical properties and resistance to cyclic loads are critically important.
A special feature of the products is the chemical purity of the steel. At least 80% of direct reduction iron is used in the production of rolled products, which makes it possible to ensure a several times lower content of impurities compared to traditional steelmaking technologies. In particular, the phosphorus content is about 0.006%, and the concentrations of non–ferrous and residual elements (chromium, nickel, copper) are ten times lower than the maximum allowable values.
The achievement of such characteristics is explained by the use of the technology of non-dom metallurgy, unique for Russia. OEMK operates according to the scheme of direct reduction of iron followed by steel smelting in electric arc furnaces. Over the past 20 years, as a result of technology optimization, scrap metal consumption during steel smelting has been reduced by more than 2.5 times, from 425 kg/t to 170 kg/t, which has improved product quality stability and reduced the impact of uncontrolled impurities.
An additional contribution to the formation of the properties of rolled products is made by the technology of high-precision hot rolling with double conversion and minimal tension. It provides a deep study of the metal structure, high accuracy of geometric dimensions and uniformity of mechanical properties along the entire length of the rolled product. As a result, the relative uniform elongation of the reinforcement has been increased by 40%, cold bending by 2 times, and impact strength at -60 °C by more than 300% compared to the metal products on the market.
