SU781218A1 - Method of low-alloy steel production - Google Patents

Description

a ton of steel, and 30-40% of aluminum in the mold is injected during its filling with metal by 20-30%, and 60-7O% - in the filling of the mold for 40-50%. The introduction of silicon into the ladle of silicon and manganese-containing ferroalloys together with aluminum in the amount of 6OO-900 g / provides mainly the binding of oxygen into aluminosilicate inclusions, their removal into slag and the production of aluminum in steel from 0.005 to 0.015%, which is still insufficient for obtaining the necessary microstructures of rolled products and its mechanical properties. In addition, there is still a significant residual amount of silicate non-metallic inclusions in the steel, to remove which, the first portion of aluminum is introduced during casting in the amount of 30-40% of the amount introduced into the mold. A reduction in the amount of aluminum of less than 30% leads to a decrease in the efficiency of steel processing and does not ensure the formation of easily aluminous inclusions made of steel, and an increase in consumption of more than 40% leads to an increase in the aluminum carbon and a decrease in its absorption. Technological methods prior to the introduction of the second portion of aluminum, prepare low-alloy steel for final deoxidation and alloying. The second portion of aluminum provides a stable aluminum content in steel from ingot to ingot. Of great importance for improving the quality of steel is the time of entry of the first and second portions of aluminum. The first portion must be added during the filling of 20% to 30% of the given ingot height, since with the earlier aluminum addition, most of it is in the bottom part of the ingot, which during rolling is cut, and the late addition reduces the uniform distribution of aluminum over ingot. The introduction of aluminum must be fully implemented when the lower half of the ingot is cast, so that during the casting of the upper part of the ingot it is necessary to use the impact of the metal to agitate it and create conditions for the uniform melting of the aluminum. Example. The low alloyed steel is smelted in a two-bath steel-smelting furnace, with an intensive purging of the bath with oxygen, and 10 minutes after the end of the purging, the smelting is released into the ladle. During the production, aluminum, manganese-containing ferroalloys (silico-manganese and ferrosilicon) are introduced into the ladle together with aluminum in the amount of 800 g / t of steel. The metal is poured from above from a double-stop ladle through a steel-teeming cup with a channel diameter of 60 mm into upward-extending molds with profitable extensions for ingots weighing 1310 O kg and height 240 O mm. During casting, after filling 25% of the specified ingot height (which corresponds to 15 seconds of casting after opening the stopper), the first portion of aluminum in the amount of 120 g / t (40% of its total amount) is introduced into the mold, and after filling the mold to a height of 40% - the second portion of aluminum in the amount of 180 g / t (60%). After filling the profitable part of the good man, lunkerite in the amount of 1.5 kg / ton of steel is poured onto the ingot mirror. The time of introduction of portions of aluminum and the ratio of the amount of aluminum between portions, as shown in Table. 1, have a decisive influence on the distribution of the height of the ingot. Aluminum is optimal in two portions, with the amount of aluminum in the first portion being 30-40% of that entered into the mold, and the additive of the first portion corresponds to a filling time of 20-30% and the second portion is 4O-5O% of the set height merging - ka (examples 2-4). Table 2 shows the effect of the ratio of operating parameters on the quality of steel. As can be seen from the table, in the metal produced in accordance with the proposed method (examples 8-13), the highest absorption and uniform distribution of aluminum, low oxygen content and non-metallic inclusions . In addition, the yield of steel obtained by the proposed method above. Thus, the proposed method allows to increase the degree of assimilation and uniformity of distribution of aluminum in steel, reduce the content of non-metallic inclusions and increase the yield of good steel.

Table 1

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(9781218, 10

Claims (1)

Claims and non-metallic contents including low alloy alloyed bucket in quantity steel, including the smelting of metal in 6OO-9OO g per ton of steel, and in the above-mentioned smelting unit, its output to $ 30–40% of aluminum is given during bucket, deoxidation and alloying in the cove-filling g) metal by 2-30%, and higher than silicon, manganese and aluminum, 6O-70% - when filled to 4O-50%. casting in molds and deoxidation of alu-sources of information, min. 250-35 g per ton of steel in pro- itftft HTTiie into account with the expert of its filling process, distinguishing- "b 1. USSR author's certificate u and with the fact that, with the aim of higher-m, 621740, cl. C 21 C 7/00, 1976, neither the degree of assimilation and uniformity. 2. Transactions about the andian Dnsti distribution of aluminum in steel, reducing the tute of f etaE5.1Q7b, v.29, / е4, p.2fe2-268 Research institutes and increasing the yield of suitable steel,