SU1696494A1 - Method of making low-carbon high-alloy steel - Google Patents

Abstract

This invention relates to the steel industry. The purpose of the invention is to increase the degree of desulfurization of the metal, reducing the invention relates to the ferrous metallurgy and can be used in the production of high-alloyed low carbon steel. The purpose of the invention is to increase the degree of desulfurization, reduce the consumption of deacidants, increase the durability of the refractory lining of the unit and increase the productivity of the furnace. consumption of deoxidizers, increase the resistance of the refractory lining of the unit and increase the productivity of the furnace. In the arc furnace, the intermediate product is smelted. The intermediate product is processed by aluminum-containing materials in a ladle. Slag and intermediate products are discharged into a ladle with an outlet located in the wall of the ladle. The rate of inclination of the furnace in the first 5-35 seconds of discharge of the melt from the furnace is (0.08-0.12) 1 / sleep each kg / t of steel of aluminum-containing materials seated in the ladle. After this, the furnace tilt speed is increased by 1.5-4.5 times and the output of the intermediate product ends at the set speed. Then, the semi-finished product without slag is continuously transferred into the aggregate by tilting the bucket, for which the bucket tilting rate in the first 1-5 seconds of the semi-finished product overflow into the aggregate is maintained at (0.10-0.22) x 1 / s for every 0, 0001 mass fraction of sulfur removed from the metal in the unit. After that, the tilt speed of the bucket is reduced in 1,5-3,5 times and finish with the set speed overflow of the intermediate product. 1 tab. Example. The semi-finished steel 08-12X18H10T is smelted in 40-ton electric arc furnaces. The final decarburization of the metal is carried out in a gas-oxygen refining unit. Before the intermediate product is discharged into the ladle, the mass of furnace slag is measured in terms of its thickness in the furnace bath, the slag oxidation (using an UKOS device). Using this information to the bottom of the ladle prisavat rus about o b.

Description

appropriate amount of aluminum-containing materials.

Depending on the amount of aluminum-containing materials introduced, a different inclination rate of the furnace is carried out at different periods of semi-finished product release. The slope speed is determined using a graded model.

In the first 2-40 seconds of production, the inclination rate of the furnace is maintained at (0.06-0.15) 1 / С-for each kg / t of steel of aluminum-containing materials, seated in a ladle. Then, the furnace tilt speed is increased by a factor of 1.2-5.0, and at the set speed, the semi-product ends up in the ladle, which has an outlet located in the ladle wall, above the level of the liquid melt. Through the outlet, the semi-finished product is released into the pouring ladle, and then into the unit or directly into the unit. In the first case, solid desulfuriators are placed at the bottom of the pouring ladle, and in the second, at the bottom of the unit.

Using a known mass fraction of sulfur in the intermediate product, the speed of the tilt of the dipper for the intermediate product overflow into another container with solid desulfates is established. In the first 0.5–6 s of the overflow of the intermediate product, the tilt speed of the bucket is maintained at the level of (0.08–0.24) –10 1 / s per each 0.0001 mass fraction of sulfur removed from the metal in the unit. Then, the rate of tilt of the blade is reduced (1.2-4.0) times and the remaining part of the metal is poured, after which the final decarburization of the metal is carried out with the help of an intensive gas-oxygen purge.

Due to the implementation of the process, the complete reduction of alloying elements from slag without the presence of silicon in the metal and inconsiderable aluminum content, the furnace slag is completely excluded in the aggregate, which, along with the preliminary desulfurization of the metal with solid slag-forming materials, increases the total desulfurization of the steel and increases resistance of the refractory lining of the unit, reducing the consumption of deoxidizers (silicon) and with a high initial mass fraction of sulfur in the metal, to an increase in productivity chi,

The results of pilot testing are presented in the table.

In addition, the overflow of the semi-product through the outlet located in the wall of the bucket simplifies the process of overflow through the large-diameter pouring cup located in the bottom of the bucket and its advantage (there is no preparation of the pouring cup, backfill, etc., which requires money and time).

Continuous overflow of the intermediate product, in contrast to the periodic, contributes to the increase in the desulfurization of steel, since it prevents the furnace slag from entering the unit.

The implementation of the invention makes it possible to organize the preferential interaction of the furnace slag with aluminum-containing materials (for example, aluminum production wastes) with the organization of effective mixing of the melt.

The use of furnace inclination speed of less than 0.08 1 / s per kg / t of steel of implanted aluminum-containing materials for a period of time less than 5 s does not ensure full discharge of furnace slag (with observed quantities) to materials, and setting the inclination rate of the furnace is more than 0, 12 1 / s for more than 35 s leads to hit

liquid metal with slag on materials. In the first case, incomplete recovery of alloying elements from slag occurs, in the second, an increase in the mass fraction of aluminum in the intermediate product,

which further adversely affects the durability of the unit lining.

In order to organize effective mixing of the metal and furnace slag, already interacting with aluminum, the inclination rate of the furnace is increased. An increase in the furnace tilt speed of more than 4.5 times leads to a deterioration in the recovery of alloying elements from slag due to a decrease in the contact time of the metal slag. Increasing the furnace tilt speed of less than 1.5 times leads to a decrease in the efficiency of the mixing processes and, as a consequence, the effectiveness of the reduction.

In addition, they arrange to fill in the intermediate converter without slag, with the absence of dissolved silicon and with a low mass fraction of dissolved aluminum. Metal pouring is organized on solid

slag-forming in the unit, for which the semi-finished product is continuously poured into the pouring ladle, and then into the unit or immediately into the unit through an outlet located in the wall of the ladle. Wherein

The tilt speed of the ladle in the first overflow section is maintained at a high level (in order to cut off the furnace slag), depending on the required degree of desulfurization of the metal.

A bucket tilt speed of more than 0.22 1 / s for every 0.0001 mass fraction of sulfur removed from the metal in the unit for more than 5 seconds can lead to an emergency situation due to the release of liquid metal.

The tilt speed of the bucket is less than 0.10 1 / s for a time less than 1 s leads to slag ingress into the unit, which worsens the desulfurization of the metal and reduces the durability of the refractory lining.

After the cut-off of the furnace slag and the first interaction of the metal with the solid desulphurisers in the unit, it is necessary for the successful desulfurization to increase the visibility of the contact of the metal with the slag, for which the ladle tilt speed is reduced. A decrease in the inclination rate of more than 3.5 times leads to an excessive decrease in the mixing efficiency of the spray jet, and less than 1.5 times to a decrease in the contact time. In both cases, the desulfurization of the metal is worsened.

Claims (1)

Invention Formula Method for the production of low-carbon high-alloy steel, including the sludge semi-product in an arc furnace, subsequent decarburization and desulfurization of the steel in the out-of-furnace assembly, which is aimed at increasing the desulfurization rate, reducing the deoxidizing agent consumption, increasing the durability of the refractory lining of the aggregate and increasing productivity, the intermediate product is processed by aluminum-containing materials in the furnace and / or bucket, slag and intermediate production in the intermediate bucket with an outlet in the wall, after which the semi-finished product without slag due to the tilt of the bucket is continuously poured into the unit at a slope speed and furnaces in the first 5–35 s of discharge (0.08–0.12) 1 / s for each kg / t of steel of aluminum-containing materials seated in the ladle, and the tilt speed of the ladle in the first 1–5 s of the semi-finished overflow into the unit support at the level of (0.1-0.22) 1 / s for every 0.001 mass fraction of sulfur removed from the metal in the unit, after which the furnace tilt speed is increased (1.5-4.5) times, and the tilt speed the bucket is reduced (1.5-3.5) times and ends at the set speed, respectively, the release and overflow of the intermediate product.