JP3027217B2 - Refining method for removing impurities in high-concentration Cu-containing iron - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an iron alloy containing 20 to 95% by weight of Cu for use in electronic materials, magnetic component materials and the like.

[0002]

2. Description of the Related Art The present inventors have proposed that Cu be 20 to 95% by weight.
Containing Cu-Fe alloy or Cr, Ti, M
Invented that a Cu-Fe alloy containing one or more synthetic components selected from o, Al, Zr, B, C, Si, and Mn has excellent performance, for example, for a lead frame. A patent application was filed in Japanese Patent Application No. 2-24504. As described in Japanese Patent Application No. 2-24504, these Cu-Fe alloy thin plates are produced by rapidly cooling a molten Cu-Fe alloy into thin cast slabs and cold rolling them. However, according to the knowledge of the present inventors, these Cu-Fe alloys have a problem that defects such as cracks are easily generated in a process of manufacturing a thin cast slab or a process of cold rolling a slab.

[0003]

SUMMARY OF THE INVENTION
As a result of further study on a method of manufacturing a thin plate of a u-Fe alloy, the present invention has been achieved. That is, according to the present invention, when a thin cast slab is produced by rapid cooling, and when the thin cast slab is cold-rolled, defects such as cracks are hardly generated.
An object of the present invention is to provide a method for producing a molten Cu-Fe alloy containing up to 95%.

[0004]

According to the present invention, Cu is set at 20.
A crude alloy melt containing about 95% by weight is used. This crude alloy melt is obtained by mixing a cold material of iron such as steel scrap and a cold material of copper such as pure copper scrap in a desired ratio and melting them in an induction electric furnace.

[0005] This crude molten metal contains about 500 ppm of oxygen, which forms internal bubbles during the production of thin cast slabs and causes cracks in cold rolling. Degrade the degree. Therefore, in the present invention, deoxidation is performed so that the oxygen content becomes 100 ppm or less. This deoxidation is performed by adding Al or Ca to the alloy melt in the atmosphere. This may be performed under reduced pressure, and the effect is equivalent to that in an air atmosphere. It is not preferable to use Si as a deoxidizing agent for removing oxygen from the molten alloy alloy, since the desulfurization effect of the present invention described later is impaired.

[0006] The deoxidized crude molten metal usually contains 50 ppm or more of S unless a special high-purity metal is used as a base metal for dissolution. This S contained in the crude molten metal causes cracks in the thin cast slab and deteriorates the cleanliness of the cold-rolled thin plate. Therefore, in the present invention, S is set to 50
Flux refining is performed to reduce the content to ppm or less. Further, although the deoxidized product is suspended in the molten metal by the above-described deoxidizing treatment, when the flux treatment of the present invention is performed, the deoxidized product is also removed, and a clean molten metal is obtained.

[0007] In this flux treatment, CaF ₂ is more than 0
20% by weight and basicity CaO / SiO ₂ (weight ratio) of 2-1
5 can be achieved by adding the flux to the treated molten metal and stirring. The flux treatment can be performed in the air atmosphere following the deoxidation treatment, but can also be performed after degassing treatment or alloy addition in a reduced-pressure vessel described later. Incidentally, CaF ₂ is you added for ease of slag formation of solid flux, refining pot, so easily melting the refractory ladle, the upper limit of 20 wt%.

In addition, Ti, Zr, S
When i is contained, these are oxidized to a non-negligible amount, and the components (basicity) of the molten flux may be changed by these acidic oxides. In this case, the basicity of molten flux during flux refining CaO / (SiO ₂ + T
It is desirable to adjust the basicity by appropriately adding CaO or a flux containing CaO during the refining process so that iO ₂ + ZrO ₂ ) falls within the range of ₂ to 15. If the basicity is excessively high, the flux does not melt sufficiently, and the refining ability decreases. Therefore, the upper limit of the basicity is set to 15, including the case of CaO / SiO ₂ containing no Ti, Zr and Si.

In the present invention, the deoxidized crude molten metal is degassed under a vacuum of 1 Torr or less. The deoxidized crude melt contains 50 to 100 ppm of nitrogen and 10 to 20 pp of hydrogen.
This [N] or [H] induces cracking during cold rolling of thin cast slabs. Therefore, in the present invention, degassing is performed so that [N] <50 ppm and [H] <10 ppm. In this degassing treatment, the molten metal is placed in a decompression container, and the atmosphere in the decompression container is set to, for example, 0.0.
This can be achieved by keeping the pressure between 1 and 1 Torr.

In the present invention, Cr, Ti, Mo, Al, Zr,
When producing a molten alloy containing B, C, Si, Mn, etc., these alloys are added to the molten metal. It is desirable to add these alloys in the decompression vessel in parallel with the degassing treatment or after the degassing treatment is completed in order to avoid the contamination of the molten metal due to entrainment in the atmosphere.

In the present invention, the molten metal is stirred during the flux treatment, the degassing treatment and the addition of the alloy. Known stirring methods such as electromagnetic induction stirring, gas injection, and mechanical stirring can be used for stirring the molten metal.

In the present invention, a known addition method such as an overhead method or a gas injection method can be used for adding a flux material or an alloy.

In the present invention, when the flux treatment is performed in a reduced pressure vessel, the order of the flux treatment, the degassing treatment and the addition of the alloy is not particularly limited. That is, the order and time of the treatment may be appropriately determined according to the H and N contents of the alloy to be added and the reactivity with the flux, or the H and N contents of the used flux. After all the processes are completed, the inside of the decompression vessel leaks with argon gas and taps out.

[0014]

EXAMPLES The present inventors produced 1 ton of molten iron containing high concentration of Cu shown in Table 1 in the following steps. Production of crude molten metal (low-frequency induction melting furnace) → Deoxidation of ladle after receiving steel (Al: 0.1)
2kg / ton, Ca: 0.2kg / ton) → Degassing (contain ladle in decompression vessel, pressure: 0.1 Torr, electromagnetic induction stirring, processing time: 15 minutes) → Component adjustment (required amount of alloy) Add material, pressure: 10 Torr) → flux refining (pressure: 1)
0 torr, flux agent: 5 kg / ton, electromagnetic induction stirring: 15 minutes) → Argon leak → Removal from vacuum container The molten metal in the ladle removed from the vacuum container was 2 mm thick by a twin roll continuous casting apparatus. A thin plate slab was cold-rolled into a thin plate having a thickness of 0.2 mm.

[0015]

[Table 1]

Nos. 2 to 5 and Nos. 7, 8, and 9 in Table 1 are as follows:
Deoxidation, degassing, alloy addition, and flux treatment are performed by the method of the present invention, and the content of impurities in the molten metal after the treatment is low. For this reason, the properties of the thin slab were good, and the cold rolling could be performed smoothly.

Nos. 6 and 10 in Table 1 are comparative examples, and the flux content and the degassing process were not performed, so that the content of impurities in the molten metal after the process was high. For this reason, blow holes were generated in the thin plate slab, and cracks were frequently generated during cold rolling.

[0018]

By implementing the present invention, Cu is reduced to 2
In the production of a Cu-Fe alloy containing 0 to 95% by weight,
It is possible to produce a sound thin cast slab, and it is possible to prevent cracks from occurring during cold rolling.

Claims (3)

(57) [Claims] 1. A Cu-Fe containing 20 to 95% by weight of Cu.
The alloy melt is deoxidized with Al and / or Ca, and then C
A flux treatment in which aF ₂ is more than 0 to 20% by weight and a basicity of CaO / SiO ₂ (weight ratio) is 2 to 15 under a reduced pressure of 1 Torr or less under atmospheric pressure or reduced pressure. A refining method for removing impurities of high-concentration Cu-containing iron, which comprises performing degassing. 2. Cu-Fe containing 20 to 95% by weight of Cu.
The alloy melt is deoxidized with Al and / or Ca, and then C
A flux treatment is carried out at atmospheric pressure or under reduced pressure using a flux having an aF ₂ of more than 0 to 20% by weight and a basicity of CaO / SiO ₂ (weight ratio) of 2 to 15, and an alloying agent is added under reduced pressure. A refining method for removing impurities in high-concentration Cu-containing iron, comprising performing a component adjustment process and a degassing process performed under reduced pressure of 1 Torr or less. 3. The content of impurities after refining for removing impurities is [H] <10 ppm, [O] <100 ppm, [N] <5.
0 ppm, [S] <50 ppm,
The refining method according to claim 1 or 2, wherein impurities of high-concentration Cu-containing iron are removed.