SU1524965A1 - Ladle slide gate - Google Patents

Abstract

This invention relates to metallurgy, in particular to devices for casting and processing steel in a ladle. The purpose of the invention is to increase the efficiency of the purge. The shutter contains a bucket glass 1, a fixed 2 and a movable 3 sectional plates, a collector glass 4, an injection tube 5 with an output inclined section 7. The angle of inclination of the output section 7 between the axis of the output section and the vertical is 15-40 °, and its length is 8 -14 internal diameters of the tube 5. Making the tube 5 with the output inclined section 7 allows you to shift the bubbling area from the wall of the bucket to its axis, which increases the efficiency of the mixing effect of gas, which allows to obtain a lower sulfur content in the finished metal and, as a result, ltate, reduce the number of marriage. 1 ill., 1 tab.

Description

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This invention relates to metallurgy, in particular to devices for casting and processing steel in a ladle.

The purpose of the invention is to increase the efficiency of purging.

The drawing shows a general view of the curved bucket bolt.

The shutter contains a bucket glass 1, a fixed and movable refractory plates 2 and 3 with pouring holes, a collector glass 4, an injection tube 5 for purging metal with gases located in the filling holes of refractory plates 2 and 3 of KOBnjoBoro glass 1 and a collector glass 4 and refractory filling 6 of the bucket glass 1. The injection tube 5 is provided with an outlet section 7 having an inclination in the direction of the axis of the bucket. The angle a between the axis of the outlet section 7 of the tube 5 and the vertical is 15-40 °, and the length of the output section 1 is 8-14 inside diameters of the injection tube 5. The refractory backfill 6 of the bucket cup I is a refractory powder with a fraction of 3-6 mm in the amount of 40-70%, the rest is small fraction up to 3 mm. Magnesite is used as a refractory powder.

The device works as follows.

The gas through the injection tube 5 from its outlet section 7 enters the bucket volume and causes the stirring of the liquid steel. The gas jet directed toward the ladle axis involves large masses of the metal volume in convective liquid flows.

A free gas jet near the bucket axis is crushed into bubbles that float on the metal surface. At the end of the metal purge, the gas supply is stopped, the gate valve is shut off, and a ladle is supplied to cast steel.

The implementation of the injection tube 5 with an output inclined section 7 having a slope in the direction of the bucket axis allows displacement of the bubbling zone from the bucket wall to its axis, which increases the efficiency of the mixing effect of gas compared to the vertical position of the tube.

To evaluate the effectiveness of the mixing intensity of liquid steel, an industrial test was conducted in a 100-ton KOBUje.

As a criterion of the efficiency of mixing, an indicator is used - the final sulfur content in the finished metal S after purging with argon in the ladle. The completeness of the metal desulfurization process in the ladle with slag mixtures and purging with argon (other things being equal - temperature, composition and quantity of the mixture, argon consumption, etc.) depends only on the efficiency of mass transfer processes - mixing efficiency. The higher the mixing efficiency, the lower

S). For bearing steel, a satisfactory sulfur content in the finished metal is considered to be less than 0.012%, and the lower, the better the quality of steel.

Industrial research has been conducted

at a constant argon consumption of 60. The results are presented in the table.

Research has shown that

The Q output of the injection tube with a slope in the direction of the axis of the bucket can significantly improve the efficiency of the blowdown compared with the vertical position of the tube in the known gate. However, if the angle of inclination is less than 15 °

5 (run 2), the purge efficiency is reduced.

This is explained by the fact that at small angles of inclination of the tube to the bucket axis (less than 15 °), mass transfer in the whole volume of the bucket is hampered due to a slight shift of the zone

 bubbling from the wall of the bucket to its axis. When the angle a is more than 40 °, the purge efficiency also decreases. This is explained by the fact that at angles and more than 40 ° a free jet flowing into the metal (up to

5 of the beginning of the splitting into bubbles) staviats more horizontal and the zone of the beginning of its splitting mixes down. Therefore, a less efficient (for dissipating the energy of the gas) bubble mode (as compared to the jet one) gets more development in height

0 bucket, which impairs the use of jet energy, and, consequently, worsens the mixing of the liquid metal.

The ratio of length has a great influence on the mixing efficiency, and, consequently, on the efficiency of blowing.

5 of the sloping section I to the inner diameter of the tube d.

At 1 / d ms less than 8 (run 7), y1, the final sulfur content in the finished metal increases, which indicates insufficient purge efficiency. When l / d is less than 8, the stream from the outlet section of the tube is poorly formed (jet test parameters - speed, density, etc., vary greatly over its cross section), which leads to the earlier start of its fragmentation in bubbles and the development of a predominantly bubble mode.

Performing an oblique exit section with l / d 6o.iee 14 is irrational, since it does not lead to further increase

0 purge efficiency. In addition, when l / d is more than 14, there is even some deterioration in the efficiency of the purge, which is associated with the fact that with such a length it is necessary to reduce the angle of inclination a constructively (experiment Yu).

The use of the proposed device allows to obtain a lower sulfur content in the finished metal (0.006% vs. 0.009%), a lower contamination.

metal globular non-metallic inclusions, which leads to a significant reduction in the marriage of the finished product.

Claims (1)

Invention Formula The bucket gate valve, which includes a bucket cup, fixed and movable refractory plates with pouring holes, a collector bottle, and an injection tube for flushing the metal with gases. refractory plates, a bucket cup, a collector cup and a refractory backfill of the bucket cup located in the pouring holes, characterized in that, in order to increase the efficiency of the purge, the upper end of the injection tube is made inclined; pipe, and the angle of inclination between the axis of the output section and the vertical is 15-40 °.