JP2942648B2 - Powder for continuous casting of Cu and Sn steel containing steel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder for continuous casting of Cu and Sn steel containing steel.

[0002]

2. Description of the Related Art In hot working of Cu-containing steel, Cu0.
Even at less than 3%, very slight surface flaws are observed. When Cu is 0.3% or more, small cracks are generated, and Cu 0.8
%, The cracks become remarkably large.
It is known that if the amount of u is increased, the cracks are further increased as the Cu content is increased (Effects of alloying elements on steel, page 378, Seibundo Shinkosha).

[0003] In addition, the problem of the environment (disposal) of so-called playing elements such as automobiles and household electrical appliances scraps, especially scraps having high Cu and Sn, has been raised, and recycling by diluting scraps containing Cu and Sn has been proposed (1990).
Elliott Symposium Processe
dings 599).

Japanese Patent Laid-Open Publication No. 63-160752 discloses a continuous casting method for preventing a slab surface from cracking.
According to this, it has been proposed that a Ni plate is bonded to the slab side of a copper mold, a groove is provided in the plate surface in the casting direction, and ultrasonic vibration is applied to achieve high-speed casting.

[0005]

SUMMARY OF THE INVENTION The present invention provides a powder for continuous casting of molten steel having a high Cu and Sn content.

[0006]

The gist of the present invention is that CaO-
0.5-10% by weight of Ni powder having an average particle size of 100 μm or less and 1 μm or less sized to 20% by weight or less is added to a SiO ₂ —Al ₂ O ₃ —MgO—CaF ₂ —Na ₂ O-based powder. It is a powder for continuous casting of Cu-containing and Sn-containing steel.

According to the experiments of the present inventors, it has been found that Ni fine powder added to the powder for continuous casting flows together with the molten slag without being separated and Ni is alloyed into the surface layer of the slab. Although the present invention has been completed based on this finding, Ni in the present invention has an average particle size of 100 μm or less, and 1 μm or less is sized to 20% by weight or less.

Generally, CaO—Si is used as a continuous casting powder.
_{O 2 -Al 2 O 3 -MgO-} CaF 2 -Na 2 but O system is used, the addition of Ni powder that is the granulated these known powder in the present invention 0.5 to 10 wt% I do.

The Ni powder required for the surface layer alloying of the slab is 0.5
%, And preferably 2 to 5% in order to surely alloy in an amount effective for preventing cracking. If the amount is too large, the powder melting property changes and alloying occurs over the entire slab, so the upper limit is set to 10%.

It is preferable that the size of the Ni powder is large because it is difficult to oxidize. However, the size of the Ni powder is preferably 100 μm or less because the slag is easily separated and the efficiency of alloying into the surface layer is low.
The optimum value is around 0 μm. If the thickness is 1 μm or less, oxidation is likely to be large, so the content is limited to 20% by weight or less.

The powder of the present invention contains, for example, Cu ≧ 0.3
%, Sn ≧ 0.01%, which is used for continuous casting of steel to which Cu and Sn are positively added, such as molten steel or weathering steel, which is made from a scrap of a playing card element.

That is, when the slab forms scale in a continuous caster or in a heating furnace, the Ni of the surface layer of the slab becomes Cu, S
Cracks and surface flaws due to the adverse effects of n are reliably prevented.

FIG. 1 shows a Ni concentration distribution in a cross section of a slab using the powder of the present invention (analyzed by an X-ray microanalyzer).
It is. The present invention example in which 5% of Ni powder was added and the comparative example in which no Ni powder was added showed a large difference in the concentration of Ni concentrated in the slab surface layer.

[0014]

EXAMPLE A slab of Table 1 (size: 240.times.1180.times.760) was produced by melting 150 tons of scrap and continuously casting it.
0 mm) was hot-rolled to produce a hot coil having a thickness of 3.2 mm.

[0015]

[Table 1]

The casting conditions are as follows. In the curved continuous caster, the casting temperature was 1550 to 1580 ° C., the drawing speed was 1.1 to 1.2 m / min, and the powders in Table 2 were automatically supplied.

[0017]

[Table 2]

The obtained slab was charged into a heating furnace and heated.
Heated at 00 ° C for 150 minutes. Then rough rolling speed 100
The length of the bar was 45 mm, and the thickness of the hot coil was 3.2 mm with a 7-stand finishing mill.

According to visual judgment, a flaw having a length of 5 mm or more was found to be 2 m.
More than one coil was determined to be defective, and one or less coil was determined to be good. Table 3 shows the powder conditions and the results of surface flaws.

[0020]

[Table 3]

[0021]

According to the present invention, Ni added to powder can be used.
The powder is alloyed into the surface layer of the continuously cast slab, so that a steel material having excellent surface properties can be manufactured from molten steel having a high Cu and Sn content.

[Brief description of the drawings]

FIG. 1 is a chart showing Ni concentration in a cross section of a slab.

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B22D 11/00-11/22

Claims (1)

(57) [Claims] 1. A _{CaO-SiO 2 -Al 2 O 3} -MgO
-CaF ₂ -Na ₂ O based powder with an average particle size of 100
A powder for continuous casting of Cu- and Sn-containing steel, wherein 0.5 to 10% by weight of Ni powder having a particle size of 1 μm or less and a particle size of 1 μm or less is reduced to 20% by weight or less.