KR20090100173A - Aluminum based magnesium deoxidizer used in steel refining process and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A manufacturing method of Al-Mg based deoxidant used in a steelmaking process and a Mg input tool thereof are provided to improve deoxidation effect by adding Mg of 3 ~ 10 wt% having the excellent deoxidation effect in Al molten metal. CONSTITUTION: Mg or Mg alloy is put into Al molten metal by a Mg input tool(10). The Mg input toll includes an opening(12), a plurality of holes(14), and an input tool mixing unit. The opening is a container in which Mg or Mg alloy is received. The hole is formed at least one side of lateral side or bottom side. The input tool mixing unit is formed on one side.

Description

Aluminum-based magnesium deoxidizer used in steelmaking process and its manufacturing method {Aluminum based Magnesium deoxidizer used in steel refining process and manufacturing method}

The present invention relates to an aluminum-magnesium-based deoxidizer which is used to remove impurities such as carbon by using excess oxygen in the steelmaking process of an electric furnace or an electric furnace, and to remove oxygen remaining in slag and a method for producing the same. More specifically, the present invention is to remove the dross remaining in the molten aluminum after dissolving aluminum (Al) by using a reflecting furnace, and then using the Mg injection jig, the mass and plate shape corresponding to the Mg component in the deoxidizer The present invention relates to an Al-Mg-based deoxidizer and a method for producing the same, in which a suitable amount of Mg or Mg scrap is submerged and dissolved in a molten metal to be continuously cast in a mold of a certain type. Al-Mg-based deoxidizer production according to the present invention is much better in terms of quality and productivity in terms of physicochemical specifications than the surface-dissolved chilled mold method, which is a conventional batch method, and can minimize oxidation of Mg. .

In general, when dissolved oxygen is present in molten steel after the steelmaking process, these dissolved oxygen forms bubbles or oxides during the solidification process of molten steel, which causes deterioration of product quality. By adding a metal having excellent affinity, the amount of dissolved oxygen is reduced to a certain amount or less.

Representative metal deoxidizers include silicon (Si) and aluminum (Al) .Si deoxidizers are not suitable for the production of rolled products because they deteriorate the ductility of steel and impair the beauty of the surface. It is mainly used for automotive sheet steel where surface is required.

Al deoxidizer injected into molten steel reacts with oxygen in molten steel to form alumina (Al ₂ O ₃ ) slag layer. At this time, the free energy value for alumina generation is very low, so it is easy to reduce other oxides in molten steel. have.

Recently, efforts have been made to use Mg, which has a higher affinity with oxygen than Al and has a better deoxidation effect, as Mg has a high vapor pressure, which causes vigorous reaction due to Mg bubbles when added to steel, and when added to the upper part of molten steel. It is burned and cannot remain in steel, and the use of steelmaking process is limited due to lowering of the real rate. In addition, the white Mg vapor generated at this time was not able to determine the progress of the process has a problem that acts as a cause to lower the productivity and quality of the steel.

In addition, Mg is rapidly oxidized even when heated in the air, especially when it is in contact with the air in the molten state, and the strong oxidation reaction, so that the melting operation for the deoxidizer production must be carried out under very strict conditions, the manufacturing cost increases there was.

Conventionally, Al-Mg-based deoxidizer was produced by surface melting chilled mold method, which is blown by wind while pouring Al-Mg melt obtained by dissolving magnesium in the molten aluminum surface by batch method in chilled mold. A half moon shape was formed to make an Al-Mg-based deoxidizer. The conventional method as described above has various problems due to Mg oxidation as described above, which is low in quality or productivity with respect to physicochemical standards.

The present invention has been made to solve the problems appearing in the production and use of pure Mg deoxidizer and the problems of the existing Al-Mg-based deoxidizer manufacturing method, the object of the present invention is to improve the quality and productivity of the physical chemical standard and Mg It is possible to minimize the oxidation to provide an Al-Mg-based deoxidizer and a method for manufacturing the same to compensate for the disadvantages of Mg deoxidizer when used in the deoxidation of molten steel.

Other objects and advantages of the present invention will become apparent from the following detailed description, claims and drawings.

In order to achieve the above object, the present invention provides an Al-Mg-based deoxidizer continuously cast by adding Mg or Mg alloy to Al molten melt in the Al molten in the deoxidizer used in the steelmaking process. .

Al-Mg-based deoxidizer prepared by the present invention is characterized in that the Mg is 3 to 10 wt%, Al is 85 to 95 wt% and the remaining impurities.

In addition, the present invention is Al-Mg-based deoxidizer manufacturing method used in the steelmaking process, by adding Mg or Mg alloy to the Al molten Al-Mg-based deoxidizer comprising the step of continuous casting after dissolving Mg in the Al molten metal Provide a method.

Furthermore, the present invention in the jig for injecting Mg or Mg alloy into the Al molten metal during the manufacture of Al-Mg-based deoxidizer, the jig is a container type that can accommodate Mg or Mg alloy, Mg or Mg alloy on one side Provides an Mg input jig comprising a plurality of holes formed in at least one surface of the opening and the side and the lower surface provided for charging.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the Al-Mg-based deoxidizer and its manufacturing method.

Al-Mg-based deoxidizer according to the present invention is added to the molten Al by adding 3 ~ 10 wt% of Mg or Mg alloy having a purity of 95% or more in various forms such as bulk, plate or scrap and then dissolve Mg in the Al molten It is solidified by continuous casting in a mold.

Since the melting point of Mg is 650 ℃ and the melting point of Al is 660 ℃, there is no increase in temperature in the dissolution process.However, unlike Al, which can be dissolved in air as described above, Mg is violently oxidized. It is very important to keep the components uniform so that continuous casting is possible.

Therefore, the Al-Mg-based deoxidizer according to the present invention is characterized in that it is prepared by a dissolution method in the internal molten Al. When the specific gravity of Mg is 1.74, which is less than Al specific gravity of 2.70, when Mg is added on Al molten metal, Mg does not settle into the molten metal but is oxidized as it floats on the surface of Al molten metal, so that the Mg dissolving yield is greatly lowered. The dissolution method of can prevent this.

The present invention provides a specially prepared Mg input jig that can be applied when Mg is dissolved in the Al molten metal. 1 is a schematic perspective view of the Mg input jig 10 according to the present invention which can be charged into Al molten metal after filling Mg in a short time.

The Mg input jig 10 is a container type that can accommodate Mg or Mg alloy in the opening 12 for loading the Mg or Mg alloy on one side, a plurality of holes 14 formed on at least one side of the side and the bottom surface And jig connecting rods 18, which are jig agitation means provided on one side, are configured to receive Mg or Mg alloy and to be introduced into the Al molten metal.

The Mg input jig 10 may be configured in various forms including hexahedral, cylindrical, horn-large, etc., and is made of a material such as high heat-resistant steel having a high melting point. In order to prevent the Mg having a smaller specific gravity than Al from rapidly rising to the surface of the molten Al after dissolution, the Mg injection jig 10 does not form a hole 14 and thus the upper surface of the Mg injury preventing surface 16 is closed. It can be formed into a hexahedral or cylindrical configuration.

The opening 12 is a component for charging a mass, plate or scrap of Mg or Mg alloy or the like.

In addition, the hole 14 is a floating flow hole of various forms such as a circle, a square, a rhombus, a pentagon, and formed on the jig surface. The hole 14 is formed with the maximum occupancy on the lower surface and the side of the jig to induce dissolution and rapid alloying by moving the molten Al and Mg molten metal, and has a diameter of 20 to 100 mm to utilize various sizes of Mg material. It is preferred that the size of the current Mg material is 40 mm.

The jig jig connecting rod 18 is connected to the stirring power source so as to stir the Mg input jig 10 laterally to maintain the Mg component uniformly.

In order to prevent the molten Mg from rapidly rising from the jig to the surface of the Al molten metal and oxidize the molten Mg jig 10, the distance d from the surface of the Al molten metal is preferably 100 mm or more. More preferably, it is located at 100 ~ 200mm easy to observe and control the process.

By using the Mg input jig 10 according to the present invention as described above can dissolve Mg quickly and thus dissolved Mg is completely solid solution up to 300 ℃ in the range of 10 wt% or less not only in the molten state with Al but also in the solid state Because of this, the selective oxidation of Mg can be minimized.

As described above, the method according to the present invention for producing a stable Al-Mg-based deoxidizer by directly melting Mg by continuous casting using a reflection furnace is an effective and unique method of improving productivity and quality of the deoxidizer at no additional cost.

Al-Mg-based deoxidizer prepared by the present invention is 3 ~ 10 wt% Mg, 85 ~ 95 wt% Al and consists of the remaining impurities. An improved deoxidation effect of up to 120% or more can be expected compared to the conventional Al deoxidizer.

The reason for setting the Mg composition ratio to 3 to 10 wt% is selected in consideration of problems due to deoxidation effect and white lead. That is, if the Mg content is 3 wt% or less, there is a problem of low deoxidation effect, and if the Mg content is 10 wt% or more, there is a problem of white smoke generation and explosion.

As described above, the Al-Mg-based deoxidizer according to the present invention is produced by continuous casting to have a certain shape by adding 3 ~ 10 wt% Mg having excellent deoxidation effect to the inside of the Al molten metal to improve the deoxidation effect We can plan.

In addition, the manufacturing method of the Al-Mg-based deoxidizer according to the present invention can improve the quality and productivity related to the physical chemical standard and can minimize the effect of minimizing Mg oxidation.

Furthermore, by using the Mg input jig used in the present invention, it is possible to easily settle and dissolve Mg into the Al molten metal, thereby increasing the Mg dissolving error rate by up to 61% compared to the time of surface dissolution.

Therefore, the present invention will be referred to as a very useful invention in the field of deoxidizer used in the steelmaking process.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples in accordance with the gist of the present invention. .

Example  One.

In order to manufacture Al-Mg-based deoxidizer, Mg input jig (FIG. 1) capable of dissolving by dissolving Mg into Al molten metal of a reflection furnace was manufactured to increase Mg dissolution rate to 90% (Table 1). ). At this time, as shown in Figure 2, the Mg input jig 10 was placed at a distance (d) 200mm from the surface of the Al molten metal to prevent as much as possible from the surface of the light Mg molten metal. Table 1 shows the Mg real rate according to the type of deoxidizer.

Deoxidizer Type Conventional surface melting method Melt internal dissolution method (Inventive method) Al-Mg3 45% 90% Al-Mg5 37% 87% Al-Mg8 19% 80%

Example  2.

After stirring the Mg input jig 10 so that the injected Mg is dissolved in Al molten metal quickly and uniformly, one side of the Al-Mg molten metal is 50mm x 50mm (upper), 45mm x 45mm ( Bottom), 15 mm (height) square ingot-shaped ingot was cast. Al and Mg contents were measured with respect to the deoxidizer cast by each Example. The measurement results are shown in Table 2 and FIG. As shown in FIG. 3, the higher the Mg content, the more severe the change of Mg component, and thus the shorter the interval between inputs.Then, the yield of Mg is 8% lower than that of the 3 wt% Mg deoxidizer, and the oxidation loss is reduced by 10%. You can see plenty. This means that the component deviation increases after and before Mg addition, but the average component is maintained. Table 2 shows the change of Mg component in the melt according to the change of Mg input amount and input time during the continuous casting process.

Deoxidizer Type Input amount (Kg) Time interval (minutes) Ingredient Mg yield Immediately after 1th input Before 2th input Al-Mg3 185 60 3.2 wt% Mg 2.9 wt% Mg 90% Al-Mg5 215 40 5.3 wt% Mg 4.8 wt% Mg 87% Al-Mg8 280 30 8.5 wt% Mg 7.5 wt% Mg 80%

Note) 5.5 ton / h continuous production standard

Example  3.

Next, the results of experiments on the deoxidation effect of the Mg component change are shown in FIG. 4. The experiment was carried out in a 100 ton converter (LD-Converter), and the effect was analyzed by the amount of dissolved oxygen (<5ppm) that was reduced to a certain level by adding a certain amount of deoxidizer. As a result, 92 wt% Al-3 wt% Mg deoxidizer shows the highest rate of deoxidation effect increase compared to the 95 wt% Al deoxidizer.

The above experimental results show that the deoxidizer having a composition within the scope of the present invention is excellent in deoxidizing ability.

Although specific portions of the present invention have been described in detail above, it will be apparent to those skilled in the art that these specific techniques are merely preferred embodiments, and thus the scope of the present invention is not limited thereto. Therefore, the substantial scope of the present invention will be defined by the appended claims and equivalents thereof.

1 is a schematic perspective view of the Mg input jig for injecting Mg or Mg alloy into the Al molten metal during the production of Al-Mg-based deoxidizer according to the present invention.

Figure 2 is a view showing the position inside the molten Al of the Mg injection jig according to the present invention.

Figure 3 is a graph showing the Mg component change in the Al-Mg molten metal according to the Mg input interval during the production of Al-Mg-based deoxidizer according to the present invention.

Figure 4 is a graph showing the deoxidation capacity of the Al-Mg-based deoxidizer according to the present invention.

Explanation of symbols on the main parts of the drawings

10: Mg input jig 12: opening

14 hole 16: Mg injury prevention surface

18: jig connecting rod for stirring

Claims (10)

In the deoxidizer used in the steelmaking process, Al-Mg type deoxidizer continuously cast by adding Mg or Mg alloy to Al molten metal and dissolving Mg inside Al molten metal. The Al-Mg-based deoxidizer according to claim 1, wherein the Al-Mg-based deoxidizer is 3-10 wt% Mg, 85-95 wt% Al, and the remaining impurities. In Al-Mg type deoxidizer used in steel making process, Al-Mg-based deoxidizer characterized in that the Mg is 3 to 10 wt%, Al is 85 to 95 wt% and the remaining impurities. In the manufacturing method of Al-Mg-based deoxidizer used in the steelmaking process, Al-Mg-based deoxidizer manufacturing method comprising the step of dissolving Mg or Mg alloy in the molten Al after the continuous casting. The method of claim 4, wherein the Mg or Mg alloy is introduced into the molten Al by the Mg injection jig, The Mg input jig is a container that can accommodate Mg or Mg alloy, An opening provided for charging Mg or Mg alloy on one side; A plurality of holes formed on at least one surface of the side and bottom; And Al-Mg-based deoxidizer manufacturing method characterized in that it comprises a jig stirring means formed on one side. The method of claim 5, wherein the Mg input jig is Al-Mg-based deoxidizer manufacturing method characterized in that the upper surface is a hexahedron-shaped or cylindrical with a closed Mg injury prevention surface. 6. The method of claim 4 or 5, wherein the Mg input jig is located at 100 to 200 mm from the surface of the Al molten metal. 6. The method of claim 4 or 5, wherein the Al-Mg-based deoxidizer is 3-10 wt% of Mg, 85-95 wt% of Al, and the remaining impurities are made of Al-Mg-based deoxidizer. In the jig for injecting Mg or Mg alloy into the Al molten metal during the production of Al-Mg-based deoxidizer, The jig is a container that can accommodate Mg or Mg alloy, An opening provided for charging Mg or Mg alloy on one side; And Mg input jig characterized in that it comprises a plurality of holes formed on at least one side of the side and bottom. According to claim 9, The jig jig for Mg input, characterized in that further comprises jig stirring means.

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