KR102286427B1 - Manufacturing method of deoxidation alloys and deoxidation agnet by using the same - Google Patents

Abstract

The present embodiments may provide a method for manufacturing iron deoxidized alloy and iron deoxidized alloy manufactured using the same. According to an embodiment of the present invention, a method for manufacturing iron deoxidized alloy comprises the steps of: putting molten metal into a refining furnace; decarburizing and refining the molten metal; and dissolving by putting aluminum in the decarburized refined molten metal. The step of dissolving by adding the aluminum may be performed in a carbon content of 0.1 to 6.5 wt% based on the entire molten metal.

Description

Manufacturing method of iron deoxidation alloy and iron deoxidation alloy manufactured using the same

This embodiment relates to a method for manufacturing deoxidized iron alloy. More specifically, it is possible to further improve the deoxidation efficiency in the steelmaking process by manufacturing the iron deoxidized alloy having a high aluminum content.

When dissolved oxygen is present in the molten steel, the dissolved oxygen generates bubbles or oxides during the solidification process of the molten steel, thereby deteriorating the quality of the product. Therefore, in the steelmaking process, a deoxidation operation is required to reduce the amount of dissolved oxygen to a certain amount or less.

For this deoxidation operation, a metal having excellent affinity with oxygen is added, and in general, aluminum is mainly used as such a metal deoxidizer.

As such, aluminum used in the decarburization process has a size of around 5 cm and a specific gravity of 2.7, which is lower than the specific gravity of molten steel of 7.5, so it floats on the surface of the molten steel and causes oxidation loss due to atmospheric contact during the melting process, and the oxidized aluminum is Al ₂ O _It is slaged in the form of 3.

As such, when aluminum is used as a deoxidizer, the loss rate of the input aluminum is high, which causes an increase in manufacturing cost.

Therefore, it is urgent to develop a deoxidizer with excellent deoxidation efficiency for an efficient steelmaking process.

In this embodiment, to improve the efficiency of the deoxidation process, it is intended to provide a method for manufacturing iron deoxidized alloy having a high aluminum content and a deoxidizer manufactured using the same.

A method of manufacturing an iron deoxidation alloy according to an embodiment includes: inputting molten metal into a refining furnace; decarburizing and refining the molten metal; And it includes the step of dissolving by adding aluminum to the decarburization-refined molten metal, the step of dissolving by adding the aluminum may be performed in a carbon content range of 0.1 to 6.5 wt% based on the entire molten metal.

Iron deoxidation alloy according to another embodiment is manufactured by the manufacturing method according to an embodiment, based on the total iron deoxidation alloy, manganese 40 wt% to 80 wt%; 1 wt% to 30 wt% aluminum; 0.1 wt% to 6.5 wt% carbon; And the remainder may include iron (Fe) and unavoidable impurities.

Conventionally, in order to improve the deoxidation efficiency, after the manganese ferroalloy was added in the deoxidation process, aluminum was additionally added. However, when the deoxidizer manufactured by the method for manufacturing iron deoxidation alloy according to an embodiment is applied, the deoxidation efficiency can be remarkably improved by only one input of the deoxidizer in the deoxidation process.

In addition, in the case of deoxidized alloy iron manufactured by the method according to this embodiment, as AlN is crystallized during the aluminum melting process in the refining furnace compared to general alloy iron, which is difficult to control nitrogen, it is easy to manage the nitrogen component in the final product, thereby reducing the absorption problem. can be resolved

1 is an exemplary view of an apparatus capable of manufacturing a deoxidizer according to a method for manufacturing iron deoxidation alloy according to an embodiment.
2 is a graph showing the amount of aluminum dissolved according to the carbon content of the molten metal.
Figure 3 shows by way of example a method for manufacturing iron deoxidized alloy according to the manufacturing method of the present invention in Examples.

Terms such as first, second and third are used to describe, but are not limited to, various parts, components, regions, layers and/or sections. These terms are used only to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, a first part, component, region, layer or section described below may be referred to as a second part, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is for the purpose of referring to specific embodiments only, and is not intended to limit the invention. As used herein, the singular forms also include the plural forms unless the phrases clearly indicate the opposite. The meaning of "comprising," as used herein, specifies a particular characteristic, region, integer, step, operation, element and/or component, and includes the presence or absence of another characteristic, region, integer, step, operation, element and/or component. It does not exclude additions.

When a part is referred to as being “on” or “on” another part, it may be directly on or on the other part, or the other part may be involved in between. In contrast, when a part refers to being "directly above" another part, the other part is not interposed therebetween.

Although not defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Commonly used terms defined in the dictionary are additionally interpreted as having a meaning consistent with the related technical literature and the presently disclosed content, and unless defined, they are not interpreted in an ideal or very formal meaning.

In addition, unless otherwise specified, % means weight %, and 1 ppm is 0.0001 weight %.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

The method of manufacturing iron deoxidized alloy according to an embodiment may include inputting molten metal into a refining furnace, decarburizing and refining the molten metal, and injecting and dissolving aluminum into the decarburized and refined molten metal.

1 exemplarily shows an apparatus capable of manufacturing a deoxidizer according to a method for manufacturing a deoxidizer according to an embodiment.

Referring to FIG. 1 , the refining furnace 100 may be used for manufacturing deoxidized iron alloy according to an embodiment.

In general, the tapping temperature of the electric furnace is 1260 to 1300 degrees, but the refining furnace 100 shown in FIG. 1 is easy to use in a temperature range higher than the tapping temperature of the electric furnace.

In order to manufacture a deoxidizer according to an embodiment, first, molten metal is put into the refining furnace 100 .

The molten metal may include 70 to 85% by weight of manganese, 6.5 to 7.5% by weight of carbon, 0.01% by weight or less of aluminum, the balance iron (Fe), and unavoidable impurities, based on the entire molten metal.

After the molten metal is charged into the refining furnace 100, a step of decarburizing refining is performed.

The decarburization refining was performed by top blowing oxygen into the refining furnace at a flow rate of ^{2500 to 3500 Nm 3 /hr using a top blowing means.}

In the decarburization process of ferromanganese, manganese and carbon are oxidized in one step by blowing oxygen from the top. As described above, the molten metal is heated from a temperature of 1250 to 1280 degrees to 1400 to 1500 degrees by the oxidation heat in which manganese and carbon are oxidized. At this time, the main heat of temperature increase of the molten metal is due to manganese oxidation as shown in Equation 1 below.

[Equation 1]

Mn + 1/2 O ₂ = 2MnO, △G° = 97683 - 21.317T (cal)

Next, the decarburization reaction is actively performed at a temperature of 1400 degrees or more, and as shown in Equation 2 below, the molten metal temperature rises up to 2000 degrees or more during the blow tempering process. Accordingly, aluminum dissolution is easily achieved in the subsequent process.

[Equation 2]

C + 1/2 O ₂ = CO, △G° = -27108 - 20.576T (cal)

That is, a step of dissolving aluminum by putting aluminum into the decarburization-refined molten metal is performed.

2 shows the amount of aluminum dissolved according to the carbon content of the molten metal.

Referring to FIG. 2 , when aluminum is added to a certain amount or more, Al ₄ C ₃ is precipitated as shown in FIG. 2 according to the carbon content of the molten metal. That is, _{since aluminum cannot be further dissolved at the point where Al 4} C ₃ is precipitated, the amount of aluminum can be determined with reference to the graph of FIG. 2 .

In the decarburization refining step as described above, even after the decarburization refining reaction is finished, the refining furnace maintains a high sensible heat of 1500 degrees or more. Therefore, it can be used to melt aluminum.

In the decarburization refining step, the carbon content was controlled to be in the range of 0.1 wt% to 6.5 wt% so that the carbon could be utilized for each steel type after the steelmaking process.

A step of dissolving aluminum was added to the decarburized and refined molten metal as described above.

The step of dissolving by inputting the aluminum includes the step of taking up oxygen and an inert gas, and the oxygen and the inert gas can be taken up at a flow rate of ^{100 to 2000 Nm 3 /hr, respectively, using the upper blowing means 10 .} there is. In this case, the inert gas to be taken up may be an argon (Ar) gas or a nitrogen (N ₂ ) gas.

As such, when oxygen and an inert gas are blown into the upper blowing means, it is possible to prevent an oxidation reaction from occurring due to the inflow of air when aluminum is input.

In addition, the step of dissolving by inputting aluminum includes the step of sieving the inert gas, and the inert gas may be simmered at a flow rate of ^{100 to 1000 Nm 3 /hr using the odor control means 20 .} Here, the odor control means 20 may mean a Tuyere located in the lower portion of the refining furnace 100 . In addition, the inert gas to be stored may be argon (Ar) gas or nitrogen (N ₂ ) gas.

When an inert gas is blown into the odor control means as described above, the stirring force of the molten metal may be increased so that aluminum may be more easily dissolved.

The amount of aluminum added in the step of dissolving the aluminum may be added so as to be in the range of 1 wt% to 30 wt% based on the final product, that is, the iron deoxidized alloy prepared according to this embodiment.

In the actual process, according to the deoxidation alloy manufacturing method, when aluminum is put into the decarburized refined molten metal, if the amount of one input is less than 1.5 tons, the aluminum is input at one time, and if it exceeds 1.5 tons, it is divided into 1 ton units. can be put in

When aluminum is input, the blowing of oxygen and inert gas through the upper blowing means can be maintained as much as possible to prevent aluminum from being oxidized and lost according to the inflow of external air.

In addition, oxygen and inert gas input at this time also serves to compensate for heat loss and increase the stirring force in order to efficiently dissolve aluminum.

In this embodiment, the components of the molten metal at the time when the dissolution of aluminum is completed are 40 to 80% by weight of manganese, 1 to 30% by weight of aluminum, 6.5 to 0.1% by weight of carbon, 0.02% by weight of nitrogen, based on the total molten metal, The remainder may include iron (Fe) and unavoidable impurities.

The method of manufacturing iron deoxidized alloy of this embodiment further includes a steel taping step after the step of dissolving by adding aluminum.

Therefore, the step of dissolving by adding the aluminum may be performed from the end of the decarburization refining step to just before the steel tapping step.

The deoxidizer manufacturing method of this embodiment may further include the step of excluding slag from the molten steel tapped after the step of tapping and arranging the molten steel from which the slag is excluded.

At this time, since continuous oxidation may occur after the aluminum input is completed, steel tapping and slag removal should be carried out quickly.

When the main line treatment is completed, that is, in the final deoxidized iron, based on the total, 40 to 80% by weight of manganese, 1 to 30% by weight of aluminum, 0.1 to 6.5% by weight of carbon, 0.005 to 0.02% by weight or less of nitrogen, and the remainder iron (Fe) and unavoidable impurities.

That is, it can be seen that about 1 to 1.5% of aluminum is oxidized and lost in the slag exclusion and main line treatment process.

The iron deoxidation alloy prepared according to the method for manufacturing iron deoxidation alloy of one embodiment is based on the total, manganese 40 to 80% by weight, aluminum 1 to 30% by weight, carbon 0.1 to 6.5% by weight, nitrogen 0.05 to 0.02% by weight, and The remainder may include iron (Fe) and unavoidable impurities. In this case, the specific gravity of the deoxidizer may be in the range of 4 to 5.

On the other hand, during the manganese ferroalloy decarburization process, nitrogen absorption may occur depending on the carbon content and the inflow of external air. However, in the case of the deoxidizer prepared according to this embodiment, the nitrogen component contained in the molten metal may be crystallized into AlN during the aluminum dissolution process. That is, in the case of the deoxidizer prepared according to this embodiment compared to the general iron manganese alloy, the nitrogen content in the final product can be significantly reduced from 0.1 wt% or less to 0.02 wt% or less.

Therefore, using the deoxidized ferroalloy manufactured according to this embodiment, it is very advantageous for the production of steel grades vulnerable to nitrogen during the steelmaking process.

Hereinafter, embodiments of the present invention will be described in detail. However, this is provided as an example, and the present invention is not limited thereto, and the present invention is only defined by the scope of the claims to be described later.

Example

3 exemplarily shows a method for manufacturing an iron deoxidized alloy according to an embodiment.

As shown in FIG. 3 , after the molten metal was charged in the refining furnace, it was subjected to a decarburization refining process, and aluminum was added and dissolved. At this time, the amount of aluminum input was calculated based on a real rate of 90% to 98% to determine the input amount.

Thereafter, the steel deoxidized iron was manufactured through casting and crushing processes after slag exclusion.

The nitrogen content in the iron deoxidized alloy thus prepared was measured, and the final deoxidized iron product was put into the steelmaking process and the deoxidizer real rate was measured after the deoxidation process was completed.

At this time, the measurement of the nitrogen content in the iron deoxidized alloy was measured by analyzing the nitrogen content in the final product that went through the casting/crushing process of FIG. 3 .

In addition, to measure the real rate of deoxidation alloy iron, the real rate was measured by dividing the increase amount of aluminum weight% in molten steel compared to the amount of deoxidized iron alloy input.

The results are shown in Table 1 below.

comparative example

As in the prior art, in the steelmaking process for product manufacturing, manganese ferroalloy was added for deoxidation, and then aluminum was additionally added.

The nitrogen content of the input general manganese ferroalloy was measured, and after the steelmaking process was finished, the deoxidizer real rate was measured in the same manner as in Examples.

The results are shown in Table 1 below.

division comparative example Example Deoxidation efficiency in the steelmaking process about 68% about 80% Nitrogen content in ferroalloys < 0.1% < 0.02%

Referring to Table 1, it can be seen that, in the case of the comparative example, the deoxidation efficiency is only about 68%, but in the case of the example, the deoxidation efficiency is increased to about 80%.

In the case of the comparative example, it is considered that the inputted aluminum did not penetrate into the molten steel due to the low aluminum specific gravity of about 2.7, and the real rate of the input deoxidizer decreased due to the reaction with the atmosphere on the molten metal surface.

On the other hand, it can be seen that the deoxidation efficiency is greatly increased in the case of the embodiment using the iron deoxidized alloy prepared according to the present invention. This is considered to be because the specific gravity of the iron deoxidation alloy of this embodiment has risen to about 4 to 5 as aluminum is alloyed with manganese and iron in the process of manufacturing iron deoxidation alloy according to this embodiment. That is, the iron deoxidation alloy of this embodiment can easily penetrate into the molten steel in the deoxidation process of the steelmaking process and reduce atmospheric contact, so that the deoxidation efficiency can be remarkably increased.

In addition, in the case of the embodiment, as AlN is crystallized during the aluminum dissolution process of FIG. 3 , the nitrogen content in the final product can be significantly reduced. In other words, it is easier to manage nitrogen in the product compared to the existing general iron alloy, so it is possible to solve the problem of absorption, and when using this to produce steel that is vulnerable to nitrogen, when the iron deoxidized alloy manufactured according to this embodiment is applied, a very advantageous effect is obtained. can be obtained

The present invention is not limited to the above embodiments, but can be manufactured in a variety of different forms, and those of ordinary skill in the art to which the present invention pertains can take other specific forms without changing the technical spirit or essential features of the present invention. It will be understood that it can be implemented as Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (9)

adding molten metal to the refining furnace;
decarburizing and refining the molten metal; And
dissolving aluminum in the decarburized and refined molten metal
including,
The step of dissolving by adding the aluminum,
It is carried out in a carbon content of 0.1 to 6.5% by weight based on the entire molten metal,
The amount of aluminum added in the step of dissolving the aluminum is 1 wt% to 30 wt% based on the manufactured iron deoxidation alloy manufacturing method. According to claim 1,
The step of dissolving by adding the aluminum,
aeration of oxygen and an inert gas;
The oxygen and the inert gas, respectively, 100 to 2000Nm ³ /hr by using a top blowing means, the method for producing an iron deoxidized alloy that is taken up at a flow rate of. According to claim 1,
The molten metal input to the refining furnace is,
Based on the whole molten metal,
Manganese 70 to 85% by weight, carbon 6.5 to 7.5% by weight, aluminum 0.01% by weight or less, the balance iron (Fe) and a method for producing iron deoxidized alloy containing unavoidable impurities. According to claim 1,
The manufacturing method of the deoxidized iron alloy,
A method for producing iron deoxidized alloy further comprising a step of tapping steel after the step of dissolving the aluminum by inputting. According to claim 1,
The step of dissolving by adding the aluminum,
A method of producing deoxidized iron alloy that is carried out from the end of the decarburization refining step to just before the steel tapping step. According to claim 1,
The step of dissolving by adding the aluminum,
a step of suppressing the inert gas;
The inert gas is a method for producing iron deoxidized alloy that is ^{stored at a flow rate of 100 to 1000 Nm 3 /hr using a odor control means.} delete It is prepared by the method of any one of claims 1 to 6,
Based on the total deoxidized iron,
40 wt% to 80 wt% manganese;
1 wt% to 30 wt% aluminum;
0.1 wt% to 6.5 wt% carbon;
0.005 to 0.02 wt % nitrogen; And
Deoxidized iron containing iron (Fe) and unavoidable impurities. 9. The method of claim 8,
The specific gravity of the iron deoxidation alloy is in the range of 4 to 5 iron deoxidation alloy.

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