Technological Innovation to Improve the Homogeneity of Converter Smelting Composition

In the steelmaking process, after the converter smelting is completed, the molten steel is poured into the ladle through the converter tap;

Various alloy materials need to be added during the tapping process to achieve precise adjustment of the composition of the molten steel; the alloy materials are generally introduced from the rotating chute to the ladle when the tapping volume of the converter reaches 20%-30%, and the tapping volume Add up when it reaches 70%-80%;

During the tapping process, in order to make the alloy material melt in time and ensure the uniformity of the molten steel alloy composition, the blanking center of the rotating chute must be aligned with the molten steel injection center.

In order to achieve this goal, the current steel mill rotary chute devices adopt fixed stoppers to control the blanking position of the rotary chute body. The rotary chute device includes a rotary chute body, a shell, a rotating gear plate, a limit baffle, and a discharge Position limiter and parking position limiter, the limit baffle is fixed on the rotating gear plate, the discharge position limiter and the parking position limiter are fixed on the shell.

The electric control system and PLC control system are installed in the converter tapping operation room to realize the rotation of the rotating gear plate and drive the rotation of the rotating chute. When the limit baffle rotates from the stop position stopper position to the discharge position stopper position, it rotates The gear plate stops automatically. At this time, the blanking position of the rotating chute should be aligned with the molten steel injection center to complete the addition of alloy materials.

In the actual production process, it often happens that after the rotating chute reaches the discharge position, the blanking center and the molten steel injection center are not aligned, causing the alloy material to be unable to melt in time after being added to the ladle, and the molten steel alloy composition is uneven, and the molten steel alloy The composition hit rate is low, especially when the alloy material is added more, the unevenness of the molten steel alloy composition is particularly prominent.

2 solution

The new converter alloy material developed by Handan Iron and Steel is added to the rotating chute device, which can quickly and accurately control the position of the rotating chute blanking, and can realize the timely adjustment of the rotating chute blanking position, so that the blanking position can be automatically adjusted to the molten steel injection center. Aligned.

This kind of converter alloy material is added to the rotating chute device, which includes the rotating chute body, the shell, the rotating gear plate, the limit baffle, the discharge position limiter and the parking position limiter. The limit baffle is fixed on the rotating gear plate, The improvement is: it also includes a limiter control component fixed on the housing, the limiter control component is provided with a chute, and the discharge position limiter and the parking position limiter are installed on the limiter control component In the chute. The parking position limiter is fixed at one end of the chute of the limiter control part, and the discharge position limiter is in a sliding connection with the chute of the limiter control part.

The limiter control component is an arc-shaped plate with a chute. The curvature of the arc-shaped plate is the same as that of the shell. The width of the chute is 2-5mm greater than the width of the discharge position limiter, and the length is greater than or equal to the circle. 1/4 of the circumference of the shell.

The working process of adding this kind of converter alloy material to the rotating chute device is as follows: press the “discharge position” button before tapping, and the rotating chute body will start to rotate under the drive of the rotating sprocket. When the limit baffle on the rotating sprocket rotates When the position of the discharge position limiter is reached, the rotating gear plate automatically stops, and the blanking position center of the rotating chute body is pre-aligned with the molten steel injection center. When it is found to be misaligned, the discharge position limiter is moved Align the position in the chute; when the converter is tilted down to an inclination angle of 20%-30% of the tapping volume, press the “discharge level” button, the alloy silo will automatically open, and discharge through the rotating chute. During the process, the blanking center of the chute will always be aligned with the molten steel injection center to ensure that the alloy material falls in the impact area of ​​the molten steel injection.

3 use effect

The device realizes the timely movement of the discharge position limiter in the chute by adding a limiter control board. When it is found that the blanking center of the rotating chute and the molten steel injection center are not in the same position and cannot be centered, the discharge position is manually adjusted. The material level limiter can ensure the centering of the blanking center of the rotating chute and the molten steel injection center, which solves the problems of slow alloy melting speed, uneven melting and large composition fluctuations during the alloy feeding process, and improves the composition of the molten steel alloy. The hit rate. The device has a simple structure and significant effects, and is suitable for popularization and application in various iron and steel enterprises.

4 Economic and social benefits

4.1 Economic benefits

1) For products produced by the new technology, the average monthly scrap steel products that avoid composition fluctuations and composition segregation are about 200 tons, 600 tons of downgraded products, the price of first-class products is 3000 yuan/ton, and the price of scrap steel is 1000 yuan/ton. After the first-class product is downgraded, the price will be reduced by 150 yuan per ton, and the average monthly loss will be reduced: 200 tons × 2,000 yuan/ton + 600 tons × 150 yuan/ton = 490,000 yuan, an annual benefit of 490,000 yuan/month × December=588 Ten thousand yuan.

2) Through the use of a new type of converter alloy material rotating chute device, the overall technological level of the converter production line has been improved. After the product quality is stable, the monthly average output will increase by 1,000 tons, creating an additional benefit of about 150 yuan per ton, and the annual social benefit: 1,000 tons / Month × December × 150 yuan / ton = 1.8 million yuan.

3) Reduce equipment consumption and maintenance costs by 29,000 yuan/month, and reduce annual costs by 29,000 yuan/month×12 months=348,000 yuan.

The total of the three items: 588+180+34.8=8.028 million yuan/year.

4.2 Social benefits

The successful application of the new converter alloy material added to the rotary chute device developed by Handan has filled the gap in the technical field of domestic converter alloy material addition method control, improved the alloy melting speed and uniformity during the alloy feeding process, and can stably improve the uniformity of the converter smelting composition Performance, thereby improving the hit rate of molten steel alloy components and increasing profitability.

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