JPS62238322A - Deoxidizer for steel manufacture - Google Patents

Abstract

PURPOSE:To obtain an Al-base composite deoxidizer for steel manufacture producing a significant deoxidizing effect because of the increased bulk specific gravity by mixing Al scraps with a ferroalloy for steel manufacture and pressing the mixture to a proper bulk specific gravity. CONSTITUTION:Al scraps 3 such as Al cans and a ferroalloy 4 for steel manufacture such as HcFeMn are put in a metallic mold 1. The practically preferred amount of them is about 40-80%. They are pressed under a prescribed pressure applied through a pressurizing plate 2 to obtain an Al-base composite deoxidizer 5 for steel manufacture having 3.0-5.0g/cm<3> bulk specific gravity. When molten steel in a converter is discharged into a ladle together with slag, the deoxidizer 5 is added in the last stage of discharge. The added deoxidizer 5 settles quickly in the molten steel because of the high specific gravity, so the deoxidizer is not oxidized by the slag and contributes efficiently to the deoxidation of the molten steel.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a deoxidizing agent for molten steel, and particularly to an A5 thread composite deoxidizing agent having a large deoxidizing effect.

Prior art and its problems HLL is very widely used as a deoxidizer, grain size regulator and alloying element in the steel manufacturing process. Al
When using l as a deoxidizing agent, cast aluminum,
Alternatively, k (aluminum scrap from one can etc. is press-molded and used, but cast aluminum is expensive, so in terms of cost,
It is advantageous to use g-pressed products.

On the other hand, as a method for adding hO, a ladle addition method during tapping is usually adopted. This Affffi addition is carried out at the end of the tapping stage from the viewpoint of Ad yield, but since molten steel, slabs, etc. have already flowed into the ladle, if the specific gravity is light, it will break the slag film and enter the molten steel. It becomes difficult to melt.

The currently used cast A/ has a specific gravity of approximately 2.7, which is considered to be the limiting specific gravity, but in the case of Al press products, the bulk specific gravity is 1.0 to 2.0 y/d, compared to cast Aβ. Since it has a fairly light specific gravity, it is easily oxidized by residual slag on molten steel, and its deoxidizing effect is small.

Therefore, A7 in case of this A4123 product? Yield is 20
It is as low as ~40%.

Purpose of the Invention This invention was made in order to eliminate the drawbacks of conventional Ag pressed products, and it is an All-based composite deoxidizing product that increases the bulk specific gravity and obtains a large deoxidizing effect by adding alloy iron to A4. The purpose is to provide a drug for

The deoxidizing agent for steel making according to the present invention is obtained by press-molding a mixture of A/scrap and ferroalloy for steel making, and has a bulk specific gravity of 3.0 to 3.0.
It is characterized by being composed of an Ag-based polymerizing agent of 3 (l/c-).

Here, the reason why the ferroalloy for steelmaking is mixed with the Ae scrap is that the ferroalloy is not only a useful material for molten steel, but also has a very large bulk specific gravity. As the ferroalloy, for example, X(CFeMn ferroalloy can be used.EI C
In the case of F e Mn alloy iron, the bulk specific gravity is 7.2 to 7.4y.
/cm. When this HCF e Mn alloy iron is blended with AA scrap, the bulk specific gravity of the resulting composite press-formed product is 3.
．． Ofig/cd or higher is expected, and conventional cast A4 (bulk specific gravity approximately 2.7), Ae press product (bulk specific gravity 1.0 to 2.0)
! /rd) has a larger bulk specific gravity.

In addition, the bulk specific gravity of the Afi-based composite deoxidizer is 3.0 to 5.0.
The reason for limiting PM is that when HCFeMn ferroalloy, which is useful for molten steel and has a high specific gravity, is used, the bulk specific gravity of the composite press-formed product is 3 as described above.
．． 0-5. Oy/C4, and the bulk specific gravity is 3.07e
If it is less than d, the deoxidizing effect will be small, and if it is more than a, a y/d, further improvement in A1 yield is expected, but in practice it is 5.
This is because 0 y/14 is considered sufficient.

Specific Example: As shown in the manufacturing process of the HLL-based composite deoxidizer of the present invention, as shown in FIG. Charge HCF eMn ferroalloy (4).The blending ratio of Ad scrap and HCFeMn ferroalloy is not particularly limited, but is 40~
About 80% is practically preferable. In addition, Al scrap and I4CF
eMtx alloy is mixed separately in advance and then molded into a mold (
1) It may be charged inside. When an appropriate amount is charged into the molding die (1) and pressed with a pressure plate (2) at a desired pressure, an Al-based composite deoxidizing agent (5) is obtained.

FIG. 2 shows an example of the method of adding the Al-based composite deoxidizing agent, and here the method of adding the Al-based composite deoxidizing agent in a ladle during tapping is shown.

That is, when tapping the molten steel (7) in the converter (6) together with the slab (8) into the ladle (9), the molten steel flow αO falls at the final stage of tapping, and the All-based composite deoxidizer ( 5) Add. Since the added deoxidizing agent has a large specific gravity, it is not easily oxidized by the residual slag (a) on the self-melting steel αU in the ladle, but settles into the molten steel α9, thereby efficiently deoxidizing the molten steel.

Example: Molten steel having the composition shown in Table 1 was mixed with HCFe shown in Table 2.
A5 made by press molding a mixture of Mn alloy iron and A6 can scraps
The A5 yield when deoxidized using a composite deoxidizing agent (bulk specific gravity 3.291ed) is shown in Table 2.
Fig. 3 shows a comparison with the case where d) is used as a deoxidizing agent.

As is clear from FIG. 3, the Ae-based composite deoxidizer of the present invention showed a higher value than the conventional product.

Table 1 Composition of molten steel (%) (blank below) Table 2 Composition of Al-based composite deoxidizer (%) Effects of the invention As explained above, the Aff-based composite deoxidizer according to the present invention has a bulk specific gravity. Since it is large, it is not easily oxidized by the slag remaining on the molten steel and settles in the molten steel, which has a great effect on deoxidizing the molten steel and has the effect of significantly improving the A1 yield.

[Brief explanation of drawings]

The first meat is a schematic diagram showing the manufacturing process of the A(l-based composite 1m!! agent) according to the present invention, FIG. The figure is a diagram showing the A1 yield in an example of the present invention. 1... Molding die, 2... Pressure plate, 3... Al scrap,
4...HCFeMn ferroalloy, 5...All-based composite 1
Exciting agent, 6... Converter, 7.11... Molten steel, 8.12
...Slab. Applicant Sumitomo Metal Industries Co., Ltd. Agent Press 1) Ryo Kushu Figure 1 Figure 3 Converter end, 1) j, (C)%

Claims (1)

[Claims] A deoxidizing agent for steel making, characterized in that it consists of an Al-based composite agent having a bulk specific gravity of 3.0 to 5.0 g/cm^3 obtained by press-molding a mixture of Al scrap and ferroalloy for steel making.