JPS6167707A - Method for regulating amount of molten steel discharged - Google Patents

Abstract

PURPOSE:To avoid the deficiency of molten steel in an ingot making equipment and waste due to the excess of molten steel by properly regulating the amount of molten steel discharged from a refining equipment in accordance with the amount of molten steel necessary for the ingot making equipment. CONSTITUTION:The amount of refined molten steel discharged from a refining equipment is estimated from the amount of starting materials charged into the equipment. When the estimated amount is smaller than the necessary amount, an iron source for supplying the deficiency is additionally charged into the refining equipment, and a part receiving the charged iron source is heated to raise the temp. dropped by the charge. Thus, when refining is carried out in a converter or at the outside of the converter, the amount of refined molten steel discharged is regulated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention appropriately adjusts the amount of molten steel discharged from refining equipment according to the amount of molten steel required in ingot making equipment, and eliminates the problem of hot water shortage in ingot making equipment. The present invention relates to a method that can prevent as much as possible the waste caused by leftover boiling water.

[Conventional technology]

Molten steel refined in a converter or external refining equipment is sent from a receiving ladle to an ingot making facility and is successively made into ingots. In this case, the amount of molten steel sent to the ingot making equipment is adjusted according to the required amount of molten steel in the ingot making equipment so that there is no surplus or deficiency as much as possible. ■ Fluctuations in the amount of iron ore input for cooling due to variations in the composition and temperature of charged hot metal; ■ Fluctuations in molten steel yield due to variations in the amount of slag making materials such as burnt lime; etc. varies considerably. In this case, if the amount of hot metal tapped out is insufficient for the required amount of hot metal requested by the ingot making equipment, it will not be possible to secure the amount of molten steel required for the feeder, and casting defects such as cavities will appear, and the amount of hot metal tapped out will decrease. If there is too much, there will be excess water and some of the molten steel will be wasted. However, if cavities occur, the yield of high-quality steel ingots will drop significantly, as well as the reliability of the quality of the steel ingot as a whole. A method is adopted in which a large amount of hot water is set, and the remaining hot water produced in the agglomeration equipment is once solidified and then returned to the refining equipment. However, this method requires separate coagulation equipment to process the excess hot water, as well as transportation equipment and personnel for returning the hot water, so it is preferable in terms of equipment and workability. do not have. Therefore, it is necessary to develop a control system that can ensure the right amount of hot water depending on the amount of molten steel required in the ingot making equipment.

On the other hand, in smelting operations, computer equipment has been developed that can almost accurately predict the amount of hot water released based on input data such as the amount of iron ore charged to smelting equipment, the amount of slag forming agent, and the blow-off temperature. It is.

However, even with this equipment, the amount of hot water dispensed can only be predicted accurately, and no research has been conducted to reduce the amount of excess or deficiency in the required amount of ingots by widening the variation in the amount of hot water dispensed. However, even if we were able to accurately predict the amount of hot water,
This is because the variations in the amount of hot water produced due to the above-mentioned factors ① to ② cannot be avoided.

[Problem that the invention seeks to solve]

Under these circumstances, the present invention aims to avoid the problem of hot water shortage in the agglomeration equipment and reduce the problem of hot water surplus.
The purpose of this invention is to provide a technology that can adjust the amount of molten steel discharged from the f# needle equipment to an excess or deficiency depending on the amount of molten steel required by the ingot making equipment.

[Means for solving problems]

The present invention is a method for adjusting the amount of refined molten steel coming out when performing converter refining or outside furnace refining, and the method predicts the amount of molten steel coming out from the raw material charged to iron refining equipment and predicts the amount of molten steel coming out. If the amount of hot water is small, an additional iron source is charged into the refining equipment to replenish the shortage of molten steel, and the smelting process is performed so that the temperature drop caused by the additional charging of the iron source is recovered by heat supply. The gist lies in the fact that it does.

[Effect]

In the present invention, the required amount of molten steel in the ingot making equipment (an appropriate amount that will not cause a hot water shortage) is set in advance, and the smelting equipment is equipped with: Quantity,
■Computer equipment for predicting the amount of hot water delivered using input factors such as the temperature of hot water, etc. is installed, and the amount of hot water delivered is predicted for every 10 refining operations. As mentioned above, such a method for predicting the amount of hot water coming out has already been established, and the amount of hot water coming out can be predicted almost accurately from the above-mentioned items 1 to 2 or correction coefficients specific to the refining equipment. If the amount of hot water predicted by the computer equipment is less than the amount of molten steel required in the ingot making equipment, an amount of iron sources (iron scatter, reduced iron, iron flux, etc.) to make up for the shortage of molten steel is transferred into the smelting equipment. Charge additionally and adjust the amount of melted steel to match the required amount of molten steel. As a result, there is no fear of a shortage of molten steel in the ingot making equipment, and the occurrence of ingot defects can be avoided. Moreover, since the final adjustment of the amount of hot water discharged can be made using this method, there is no need to charge an excessive amount of raw material at the charging stage of Shima's first refining raw material, and the amount of hot water leftover from the ingot making process can be handled. Therefore, it is possible to reduce the

However, if an additional iron source is charged at the refining stage, the cooling effect accompanying the melting of the iron source will lower the tapping temperature, causing problems due to insufficient heat in subsequent steps.

Accordingly, in the present invention, heat is supplied to the refining equipment in order to prevent the deterioration of the temperature that occurs in accordance with the additional charging amount of iron source. In the case of converter refining, the heat source is a carbon-based heating agent or A
It is sufficient to use a metal heating agent such as 1 or St, and replenish the heat with the heat of combustion.
- Heat may be supplied using refining equipment equipped with a heating function such as OB. Further, depending on the case, a drop in the tapping temperature can be prevented by additionally charging the iron source in a heated and molten state into the refining equipment.

In this way, by replenishing the insufficient amount of tapped metal by additionally charging the iron source, and by replenishing the drop in molten steel temperature due to the charging of the iron source by replenishing heat during refining, the problem of a drop in the tapping temperature can be solved. In the agglomeration process, the amount of hot water generated can be reduced as much as possible without causing a shortage of hot water. By the way, Figure 1 shows the amount and frequency of surplus hot water generated in the ingot-making process (n number ) is a graph showing the results of a statistical investigation of the relationship, and FIG. 2 is a graph showing the results when the relationship was statistically investigated.

As is clear from these results, in the conventional method (Fig. 2), a considerable amount of surplus hot water is generated because the amount of iron source charged at the charging stage to the refining equipment is set too high. Despite this, hot water shortages occur quite frequently. On the other hand, when the method of the present invention is adopted, the amount of excess hot water generated is significantly reduced, and the frequency of hot water shortages is almost zero.

〔Example〕

Hot metal is refined in a converter with a charging capacity of 90 tons, and the required amount of molten steel is 87. (1 or 86.5 mm) In a series of steps of sending to an ingot making facility and making ingots, refining operations were carried out using the comparative method and the method of the present invention, and the results shown in Table 1 were obtained.

Table 1 (1 charge average) From Table 1, it can be considered as follows.

(1) Comparative method 1 aims to increase the amount of steel tapped by additionally charging only iron ore without using carbon for heating. Additional charging is not possible, resulting in a shortage of hot water during the ingot making process. On the other hand, in Method 1 of the present invention, heat is supplied by heating carbon, so the required amount of iron ore can be additionally charged, and there is no fear of running out of hot water in the ingot making process.

(2) In Comparative Method 2, the amount of Si in the hot metal is large, so C is used for desiliconization.
It is necessary to add aO and light calcined dolomite repeatedly, and the yield of iron decreases due to the increase in the amount of slag produced, resulting in a shortage of hot water. By additionally charging iron ore and adding an appropriate amount of heating carbon as a heat source, the required amount of tapped steel can be secured without substantially lowering the tapping temperature.

〔Effect of the invention〕

Since the present invention is configured as described above, it is possible to almost eliminate the occurrence of defective products due to insufficient hot water in the ingot making process, improve the reliability of the steel ingot quality, and furthermore prevent excess hot water. Since the amount of water generated is also significantly reduced, it is possible to enjoy many practical advantages, such as high processing efficiency and reduced processing work for surplus hot water.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the amount of excess vortex generation and the frequency of generation when the present invention is adopted, and FIG. M2 is a graph showing the relationship between the amount of excess vortex generation and the frequency of generation in the conventional method.

Claims (1)

[Claims] A method of adjusting the amount of refined molten steel coming out when performing converter refining or outside furnace refining, in which the amount of refined molten steel coming out is predicted from the raw material charged to the refining equipment, and when the predicted amount of coming out is small, , characterized in that an iron source is additionally charged into the refining equipment to replenish the shortage of molten steel, and the refining is performed so that the temperature drop caused by the additional charging of the iron source is recovered by heat supply. How to adjust the amount of molten steel coming out.