JPH01188642A - Mold material for continuous casting with built-in electro-magnetic mixer - Google Patents

Abstract

PURPOSE:To reduced the electric conductivity to the range where the magnetic field does not diminish, to improve the proof stress at normal temp. and the heat resistance of the title material and to facilitate its atmospheric melting by specifying the compsn. of the title mold material. CONSTITUTION:The mold material contains, by weight, 0.4-4.0% Ni, 0.1-1.0% Si, 0.05-5.0% Zn, 0.1-2.0% Sn, 0.02-1.0% Mn, 0.001-0.01 % Mg and one or more kinds among 0.001-0.01% Cr, Ti and Zr and the balance consisting of Cu. In the material, since Ni and Si form the deposits of Ni and Si contributing to the improvement of the strength, the above range must be independently incorporated thereto; and since Ni regulates its electric conductivity to the required value, <=2.0% is needed, and because of the improvement of its strength, >=0.1% is needed. The molten metal is oxidized to reduce its fluidity at the time of >0.01 % Mg. Cr, Ti and Zr improve the fining of the crystal grains of the ingot and its expansibility at high temp., but in the case of >0.01% additioning thereof, the oxidizability of the molten metal is made severe.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mold material for continuous casting that has an electromagnetic stirrer built into the mold part, and more specifically, it is used for continuous casting of steel etc. in which an electromagnetic stirrer is installed. The present invention relates to a mold material having physical and mechanical properties suitable for the mold material.

[Prior art] Recently, electromagnetic stirring has been adopted in the continuous casting method of steel.
As a result, not only the quality of ingots has been improved, but continuous casting of all kinds of steel has become possible.

Generally, thermal conductivity is important for mold materials used for continuous casting of steel, etc., and silver-containing copper or deoxidized copper has been used. However, among the mechanical properties of silver-containing copper or deoxidized copper, the room-temperature yield strength, which is important as a mold material, is less than 25 kgf/mrn' and the Vickers hardness is less than 85, and by adding an electromagnetic stirring device, As the temperature of mold materials increases, friction resistance at higher temperatures is required, and these materials are no longer able to meet the requirements.

Additionally, Cu-Cr and -Zr alloys are examples of materials with excellent heat resistance, and the electrical conductivity of these materials is equal to that of silver-containing copper and deoxidized copper, and is 80% IACS or higher.

If the conductivity is too high, the magnetic field for electromagnetic stirring is consumed by the mold material, resulting in additional power and operational costs. To address this problem, attempts have been made to lower the electrical conductivity by incorporating elements such as AiL, Sn, and Mn while maintaining the heat resistance of Cu-Cr-Zr. Since the molten metal of these alloys undergoes severe oxidation during melting and casting, it is extremely difficult to melt them in the atmosphere, which necessitates vacuum melting or melting in an inert gas atmosphere, resulting in high costs.

[Problems to be solved by the invention] In order to solve the above-mentioned problems, the present inventors have
1-106737, but the present invention is an invention that further expands the effects of the above proposal. That is, the present invention provides silver-containing copper, deoxidized copper and C
It solves the various problems of u-Cr-Zr alloys, specifically IACS with a conductivity of 25 to 45%.
We have developed a mold material for continuous casting that has a built-in electromagnetic stirrer and has the characteristics of high yield strength at room temperature, excellent heat resistance, and ease of melting in the atmosphere.

[Means for solving the problems] The present invention provides Ni: 0.4 to 4. Owt%, Si0.
1-1.0wt%, Zn: 0.05-5.0wt%
, Sn: O, 1~2.0wt%, Mn: 0.02~
1. Owt%, Mg: 0.001 to 0.01 wt%, roughly containing one or more selected from Cr, Ti, and Zr in a total amount of 0.001 to 0.01 wt%, the balance being Cu and unavoidable The gist lies in a mold material for continuous casting that incorporates an electromagnetic stirrer characterized by being made of impurities.

[Function] The continuous casting mold material incorporating the electromagnetic stirrer according to the present invention will be described in detail below.

First, the components and component ratios of the continuous casting mold material incorporating the electromagnetic stirrer according to the present invention will be explained.

Ni is set to 0.4 to 4.0 wt%.

If N1 is less than 0.4 wt%, hardly any improvement in strength can be expected even if Sl is contained in the range of 01 to 1.0%, and if N1 is contained in excess of 4.0 wt%. ,
Even if Si is contained in the range of 0.1 to 10 wt%, the formation of Ni and Si precipitates that contribute to improving the strength becomes impossible.

Further, the electrical conductivity is also less than 25%lAC3. Therefore, the N1 content is set to 0.4 to 4.0 wt%.

The content of Si is 0.1 to 1.0 wt%.

For Si, if the content is less than O, 1wt%, N1 is 0.4w
Even if SL is contained within the range of Ni
Even if it is contained in the range of 0.4 to 4.0 wt%, the formation of Ni2Si precipitates that contribute to improving the strength becomes impossible. It also reduces hot workability. Therefore, the Si content is o,i~1.0 wt%.

Zn from 0.05 to 5. Owt%.

Zn is an essential element for improving the peeling resistance of Ni plating and Cr plating, and the content is 0.05 wt%.
If the content is less than 5.0 wt%, this effect will be small, and if the content exceeds 5.0 wt%, stress corrosion cracking will easily occur. Therefore, the Zn content is set to 0.05 to 5.0%.

Sn is set to 0.1 to 2.0 wt%.

Sn improves the tensile strength and at the same time lowers the conductivity in a range where it is not attenuated by the magnetic field, i.e. 25-45% IA.
This is an element necessary for adjusting to CS. Sn is 0.1
If it is contained in an amount less than 2 wt%, the effect of improving strength is small, and if it is contained in an amount exceeding 2 wt%, it is effective in improving strength, but the electrical conductivity of 25%lAC3 or more cannot be satisfied. Therefore, the Sn content is 0.1-2
．． It is set to 0wt%.

Mn is set to 0.0:2 to 1.0 wt%.

Mn is a strip element that improves hot workability, and when the content is less than 0.02 wt%, this effect is small, and when the content is less than 0.02 wt%,
If the content exceeds %, it will reduce the dry flow properties during casting,
The yield of ingots decreases significantly. Therefore, the Mn content is set to 0.02 to 1.0 wt%.

Mg is set to 0.001 to 0.01 wt%.

Mg is an essential element for stabilizing S that is inevitably mixed in from S and S compounds contained in raw materials, furnace materials, and the atmosphere during melting, and forms MgS compounds to release copper. Fixed in alloy. Content is 0.001%wt
If it is less than this, this effect will be small and free S will exist at the grain boundaries, making intergranular cracks likely to occur in the temperature range of 400 to 600° C. during heating during hot working or during hot working. In addition, Cu+MgC contained in excess of O, O1wj%
A eutectic of u2 (melting point: 722° C.) is generated, which deteriorates hot workability, and at the same time, the molten metal is oxidized, reducing flowability and making the ingot unsound. Therefore, the Mg content is 0.0
01 to 0.01 wt%.

The total amount of one or more selected from Cr, Ti, and Zr is 0.
．． 001 to 0.01 wt%.

Cr, Ti, and Zr are elements that refine the grains of the ingot and improve its malleability at high temperatures.Especially, they are essential elements for preventing cracking during hot working, and each of the above elements is contained. However, cracking cannot be completely prevented unless one of Cr, Ti, and Zr is contained, and if the content is
, below ooiwt%, the above effect is small and 0.01
If the content exceeds wt%, the oxidation of the molten metal will be severe and a healthy casting surface will not be obtained. Therefore, Cr, Ti,
The total amount of one or more types selected from Zr is 0.001 to O
,01wt%.

[Example 7] Examples of continuous casting mold materials incorporating an electromagnetic stirrer according to the present invention will be described below.

Table 1 shows the components and component ratios of the continuous casting mold material (the alloy of the present invention in the examples) incorporating the electromagnetic stirrer according to the present invention and the comparative alloy. Invention alloy and comparative alloy N09
1 to 11 and no.

No. 13 was melted in the air while covered with charcoal in a Kributol furnace, and an ingot with a thickness of 45 mm, a width of 82 mm, and a length of 200 mm was melted using a tilting method using a cast iron book mold.

Next, after cutting the surface of this ingot by 1.5 mm each,
It was hot rolled at a temperature of 0°C to a thickness of 6mm, of which N095-8. No, 10° No, 11 and No, 1
3 is 775℃, No. 1 to 4 and No. 9 is 725
After being reheated for 30 minutes at ℃, the samples were rapidly cooled in water.

Subsequently, the former group was aged at 525°C and the latter group was aged at 475°C for 2 hours, respectively.

Comparative alloys No. 12 were melted under charcoal coating in a Kributol furnace, degassed by blowing argon gas into the molten metal, and then cast in the same manner as the alloy of the present invention.

After face-shaping the surface of this ingot by 1.5 mm each, it was hot rolled at 950°C to a thickness of 8 mm, then reheated at 925°C for 30 minutes, cooled with shower water, and scaled by pickling. , cold rolled at a rolling reduction of 40% to a thickness of 4.8 mm, and aged at 440° C. for 2 hours.

JIS No. 13 B test pieces for measuring mechanical properties and test pieces for measuring electrical conductivity at room temperature and 300° C. were sampled along the rolling direction from these plates, and the results shown in Table 2 were obtained.

The results in Table 2 show that the alloy of the present invention has a yield strength of 33 kgf/mn1″ or more at room temperature and 300°C, and has a yield strength of 25 to 45
%IACS conductivity.

Comparative materials No. 19 to No. 12 have the same mechanical properties, but the electrical conductivity is less than 25% I AC3 or 80% I
ACS or higher, and is not suitable as a mold material for continuous casting with a built-in electromagnetic stirrer.

Although a plate material is used as a method for manufacturing a mold material made of the alloy of the present invention, a back mold may also be used. The manufacturing method may be one using an extruded material or a welded pipe using a plate material.

[The effects of the invention have been explained above. As described above, since the continuous casting mold material incorporating the electromagnetic stirrer according to the present invention has the above-described configuration, it is possible to set the conductivity to a range where the magnetic field does not attenuate. Even if the thermal conductivity decreases due to a decrease in the casting rate, the mold is less likely to soften or deform, making it possible to perform continuous steel casting smoothly.
This has the excellent effect of making it possible to improve productivity and quality.

Claims (1)

[Claims] Ni: 0.4-4.0wt%, Si: 0.1-1.0w
t%, Zn: 0.05~5.0wt%, Sn: 0.1~
2.0wt%, Mn: 0.02-1.0wt%, Mg:
Contains 0.001 to 0.01 wt%, and further contains Cr, T
The total amount of one or more selected from i and Zr is 0.001
A mold material for continuous casting equipped with a built-in electromagnetic stirrer, characterized in that it contains Cu and unavoidable impurities.