SU1089147A1 - Method for reducing steel with aluminium and reducer pig - Google Patents

Abstract

1. A method of deoxidizing steel with aluminum, which includes the introduction of molten aluminum, cast iron, into the melt, characterized in that, in order to increase the absorption rate of aluminum and the quality of steel, aluminum, ut & the desired iron, is introduced into the ladle when the melt is released, and the ratio of the mass of aluminum to the mass of iron is maintained within 1:

Description

The invention relates to ferrous metallurgy, in particular to steelmaking and can be used to deoxidize and alloy steel. There is a known method of deoxidizing steel, in which an aluminum ingot made with three longitudinal ribs and having a flap shape fl in cross section is introduced into the melt. However, due to the low density of aluminum, pigs float on the surface of the metal, a significant part of the aluminum is oxidized by oxygen in the atmosphere and slag, while the absorption of aluminum is low. A known method is to deoxidize with aluminum, which includes the introduction of molten aluminum, cast iron, or steel into the molten metal, the aluminum pieces being fixed on iron rods, which are introduced through the slag layer into the steel bath and kept there for complete melting 2. The disadvantage of this method is that the metal shell burns out earlier than all the pyminium is dissolved, the latter floats to the slag, the absorption of metal aluminum is low, and the fastening of the metal is not reliable. The purpose of the invention is to improve the absorption of aluminum and the quality of steel. The goal is achieved by the fact that in the deoxidation method it has become aluminum, which includes the introduction of molten aluminum, cast iron, aluminum, iron put into the ladle when the melt is released, and the ratio of the mass of aluminum to the mass of iron is maintained within 1: (2.5 -5.0). In an aluminum deoxidation pig, an expanding layer of pig is placed in the middle of the pig, and the layer of aluminum is evenly distributed around the periphery. The drawing shows the general appearance of the steel ripple. The middle of the pig 1 is made of cast iron, a layer of aluminum 2 is evenly distributed around the periphery. The pig is made as follows: a cast-iron object is placed into the casting mold and aluminum is cast in to cover the core with a layer of a certain thickness. Removing the finished pig from the mold, loading and unloading is done with a magnet. The method of deoxidizing steel using aluminum-iron pigs is carried out as follows. The pigs with the help of a magnet out of the box are loaded by a crane into a steel-pouring ladle with the release of melting from the furnace. The pig with the mass ratio of aluminum to cast iron of 1: 2.5 is captured by the falling stream of steel and reliably penetrates into the fluid volume. By reducing the amount of pig iron in the ingots, i.e. as the proportion of iron decreases in a ratio of (1: 2.5), the pig is not held in the bulk of the liquid steel of the bucket and floats. The ingots aluminum is oxidized by oxygen of the slag and the atmosphere, which is very significant: it reduces the degree of its absorption. The consumption of aluminum under these conditions needs to be increased. It has also been experimentally established that by exceeding the amount of pig iron in the pig above the aluminum by more than 5 times, the amount of carbon introduced by the pig iron (more than 0.03%) significantly increases. So, with the consumption of aluminum of 1.25 kg / t of steel and the mass ratio of aluminum to cast iron of 1: 5, the increase in the carbon content in steel 08U was 0.025%. Also, the heat loss on the yagrev and the melting of the pig iron core increases significantly, the temperature of the steel decreases by more than 10 ° C, which worsens the conditions for casting the metal and its quality. The optimum weight ratio of aluminum to cast iron in the pig when deoxidizing steel is 1: 3.5. In this respect, minimum heat losses for heating and melting the pigs are achieved (a decrease in the temperature of the liquid steel does not exceed 5 ° C) and its reliable retention in the volume of the liquid steel in the ladle when the melt is released. The effectiveness of various deoxidation processes is carried out with the release of 08U steel from a two-bath furnace into a ladle. The data of comparative experiments are presented in the table. Option 1 - deoxidation of aluminum-iron pigs according to the proposed method (core of cast iron, aluminum shell), weight up to 25 kg. 3 Option 2 - deoxidation of an iron-aluminum ingot according to the prototype (aluminum core, cast iron shell), weight up to 25 kg. Option 3 - deoxidation with aluminum pigs (used at the combine), weight up to 15 kg. From the data in the table it can be seen that the proposed method of steel deoxidation is the most effective (option 1 / number of heats 2-4). The carbon content of the metal is minimal, the temperature reduction of the steel in the ladle is within acceptable limits, and the degree of absorption has increased at least 2 times. The exceptional effect is achieved due to the fact that the pigs for deoxidation (according to the proposed construction and technology) do not float during the production of melting, and contact with the oxidizing one. atmosphere and slag absent. Comparative tests on an industrial scale were carried out for options for deoxidation 1-3, 2-1 and 3. 1.5 thousand tons of steel 08U was cast for each option. The yield of cold-rolled thin-sheet rolled steel from steel of rayon according to the WWS category (a particularly complicated extraction of GOST 9045-80) was for option 3 - 83.9%, for option 2-1 - 84.2% and 93.4% for option 1- 3 Failure to yield, i.e. the quality of steel occurs due to the improvement of the mechanical (mainly plastic) properties of the metal itself, which ensures a stable production of the required aluminum content in steel (0.02-0.08%) close to the lower limit. The latter, in turn, is determined by a low, in comparison with other known methods, the consumption of aluminum, its high absorption and a decrease in the content of non-metallic inclusions such as aluminates.

eleven

1: 2.0 1.40

0.07

0.07 0.024

. 10891476

ABOUT

17.1

Table continuation;

20% of the ingots are found on the metal surface.

Claims (2)

1. The method of deoxidation of steel with aluminum, including the introduction of aluminum weighted by cast iron into the melt, characterized in that, in order to increase the degree of assimilation of aluminum and the quality of steel, aluminum weighted by cast iron is introduced into the ladle when the melt is discharged, and the ratio of the mass of aluminum to the mass of cast iron support within 1: (2.55.0). 2. An ingot for steel deoxidation with aluminum, consisting of a layer of aluminum weighted by a layer of cast iron, characterized in that, in order to increase the degree of assimilation of aluminum and the quality of steel, a weighting layer of cast iron is placed in the middle of the ingot, and the layer of aluminum is evenly distributed around the periphery.