JPH10225750A - Continuous casting and rolling apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the stuck-solidification of molten metal to the inner surface of a molten metal supplying nozzle, to reduce the development of linear defects on the surface of a cast plate and to improve the surface quality of the cast plate by forming the size of a recessed part in the ruggedness showing the surface roughness of the inner surface of the molten metal supplying nozzle to the size preventing the invasion of the molten metal. SOLUTION: The molten metal supplying nozzle 40 is provided with a flat cylinder nozzle body 41 and a coating part 45 composed of releasing agent coated and peripherally arranged on the inner surface of the tip part. The inner surface 46 of the coating part 45 is polished with a polishing paper, etc., and the diameter Di and the depth De of the recessed part in the ruggedness showing the surface roughness are made to the size preventing the invasion of the molten metal 1 by surface tension, etc. At the time of supplying the molten metal 1 into gap between one pair of cooling rolls from the molten metal supplying nozzle 40, the molten metal 1 is prevented to invade the molten metal into the recessed part 47 in the ruggedness of the inner surface 46 of the molten metal supplying nozzle 40 by the relation of the diameter Di and the depth De. Therefore, the unevenness of the molten metal flow accompanied with the stuck-solidification thereof by invading the molten metal 1 into the recessed part 47, is prevented and the linear defects in the surface of the cast plate is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting and rolling device for continuously casting and rolling molten metal to form a cast plate, and more particularly to a continuous casting and rolling device capable of improving the surface quality of a cast plate.

[0002]

2. Description of the Related Art Conventionally, a continuous casting and rolling apparatus has been disclosed, for example, in Japanese Unexamined Patent Publication No. Hei. Used in the manufacture of The continuous casting and rolling device includes a pair of rolls for forming a cast plate by casting and rolling a molten aluminum, and a melt supply nozzle for supplying the molten metal between the pair of rolls.

[0003]

However, in such a conventional continuous casting and rolling apparatus, a streak defect may occur on the surface of a cast plate, which causes a reduction in product yield. There is. One of the causes of the generation of the streak defect is considered to be the non-uniform flow of the molten metal due to the solidification of the molten metal on the inner surface of the molten metal supply nozzle.

[0004] The present invention has been made in view of such circumstances, and has as its object to provide a continuous casting and rolling device capable of improving the surface quality of a cast plate.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a casting and rolling mill main body for casting and rolling a molten metal to form a cast plate, and a molten metal for supplying the molten metal to the casting and rolling mill main body. In a continuous casting and rolling device having a supply nozzle,
The concave portion of the unevenness indicating the surface roughness of the inner surface of the molten metal supply nozzle is a dimension for preventing the molten metal from entering. Therefore, it is possible to prevent the molten metal from seeping into the concave portion and solidifying.

The penetration of the molten metal into the concave portion is determined by the relationship among the pressure, viscosity, surface tension, specific gravity, and the shape (diameter and depth) of the concave portion. In particular, because of the influence of gravity, the molten metal easily penetrates into the concave portion on the inner surface of the lower nozzle. In addition, the present inventors focused on the surface roughness (Ra) as an index characterizing the diameter and the depth of the concave portion. In the present invention, the average surface roughness of the inner surface of the molten metal supply nozzle was set to 1.0 μm or more. The effect similar to the above is produced by setting it to 0 μm or less.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The continuous casting and rolling device of the present embodiment is an application of the present invention to a continuous casting and rolling device used for manufacturing a lithographic printing plate support for a photosensitive lithographic printing plate. As shown in FIG. 2, the continuous casting and rolling apparatus 100 includes a pair of cooling rolls 11, 11 that form a cast plate 2 by casting and rolling a molten metal 1 of aluminum or an aluminum alloy as a casting and rolling mill body. Rolling machine 10 and winder 20 for winding cast plate 2
And a cutting machine 30 for cutting the cast plate 2 and a melt supply nozzle 40 for supplying the melt 1 to the pair of cooling rolls 11, 11
A gutter 50 connected to the molten metal supply nozzle 40;
Holding furnace 60 for storing and holding the melt, a melting and holding furnace tilting machine 65 for tilting the melting and holding furnace 60 by driving an electric motor and pouring the molten metal 1 into the gutter 50, and a level meter 7 for detecting the liquid level of the gutter 50.
0 and a control device 80 such as an amplifier for controlling the melting and holding furnace tilting machine 65 so as to maintain a desired liquid level based on the detected liquid level.

As shown in FIG. 1, the molten metal supply nozzle 40 is a flat cylindrical nozzle body 41 made of a refractory ceramic material containing calcium silicate as a main component, and is applied to the inner surface of the tip of the nozzle body 41. And a covering portion 45 made of a release material provided around. Inner surface 4 of this covering portion 45
6, that is, the inner surface 46 of the molten metal supply nozzle 40 is polished with abrasive paper or the like, and the diameter Di and depth De of the concave and convex concave portions 47 indicating the surface roughness of the inner surface 46 are changed due to surface tension and the like. 1 is sized to prevent the intrusion of the gas. In the present embodiment, the average surface roughness of the inner surface 46 of the molten metal supply nozzle 40 is set to be 1.0 μm or more and 3.0 μm or less.

The molten metal 1 held by the melting and holding furnace 60 shown in FIG. 2 is an ingot (lump) of 99.7% Al.
Al-Fe, Al-Si, Al-C
u, 0.30% Fe, S
i is adjusted to be 0.07%, Cu is adjusted to be 0.01%, and further, a crystal refiner wire 5 made of an Al-Ti-B alloy is supplied, so that Ti becomes 0.02%. It has been adjusted as follows.

Since the continuous casting and rolling apparatus 100 has the above configuration, when the molten metal 1 is supplied between the pair of cooling rolls 11 from the molten metal supply nozzle 40, as shown in FIG. The molten metal 1 is prevented from seeping into the concave and convex recesses 47 on the inner surface 46 of the molten metal supply nozzle 40 due to the relationship between the diameter Di and the depth De. Therefore, the molten metal 1
Since it is prevented from seepage and solidification, the uneven flow of the molten metal due to the solidification can be prevented, and the occurrence of streak defects on the surface of the cast plate 2 in FIG. 2 can be reduced. Therefore, the surface quality of the cast plate 2 can be improved.

Here, the surface roughness (Ra) may be used as an index characterizing the diameter Di and the depth De. Further, in the above-described embodiment, since the wettability of the inner surface 46 is reduced by forming the covering portion 45 of FIG. 1 with a release material, the solidification of the molten metal 1 on the inner surface 46 can be further prevented. it can.

Further, in the present embodiment, the thus formed cast plate 2 of FIG. 2 is subjected to cold rolling, heat treatment for annealing, and straightening by a roller, and then the surface is mechanically and Alternatively, the support is roughened chemically, electrically, or electrochemically to obtain a lithographic printing plate support. A photosensitive coating film is provided on this lithographic printing plate support, image-exposed, developed and plate-made to obtain a photosensitive lithographic printing plate. This photosensitive lithographic printing plate can be manufactured with high quality along with the improvement of the surface quality of the cast plate 2, and particularly, in the case of electrochemical surface roughening using anodizing treatment, streak defects are remarkable. Therefore, ensuring the surface quality of the cast plate 2 is an important requirement.

[0013]

FIG. 3 shows the inner surface 4 of the melt supply nozzle 40 of FIG.
6 is a table showing experimental results comparing the surface quality of the cast plate 2 of FIG. 2 when variously changing the surface roughness of No. 6 and the presence or absence of a covering portion 45 made of a release material. In this experiment, Fe was 0.3
0%, 0.07% Si, and 0.1% Cu.
An aluminum melt 1 containing 0.1% and 0.02% of Ti was cast on a twin roll continuous casting and rolling mill 10
Then, after forming a cast plate 2 having a thickness of 7 mm and a width of 200 mm,
Cold-rolled to a thickness of 1.5 mm, annealed at 480 degrees Celsius for 10 hours, cold-rolled again to finish to a thickness of 0.235 mm, and then subjected to electrochemical surface roughening. Whether or not streaks were formed on the treated surface and whether or not Fe and Si were segregated were evaluated.

From the chart showing the experimental results (FIG. 3), it was confirmed that under the above conditions, it is preferable that the average surface roughness of the inner surface 46 of the melt supply nozzle 40 be 1.0 μm or more and 3.0 μm or less.

[0015]

As described above, according to the continuous casting and rolling apparatus of the present invention, the solidification of the molten metal on the inner surface of the molten metal supply nozzle can be prevented, so that streak defects on the surface of the cast plate can be prevented. Can be reduced. Therefore, the surface quality of the cast plate can be improved.

[Brief description of the drawings]

FIG. 1 is a partially enlarged longitudinal sectional view showing a molten metal supply nozzle of a continuous casting and rolling apparatus of the present invention.

FIG. 2 is an overall view of a continuous casting and rolling device of the present invention.

FIG. 3 is a table showing experimental results comparing the surface quality of a cast plate when the surface roughness of the inner surface of a molten metal supply nozzle and the presence or absence of a coating portion made of a release material are variously changed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Molten metal 2 ... Cast plate 10 ... Twin roll continuous casting and rolling machine (casting rolling machine main body) 40 ... Molten supply nozzle 46 ... Inner surface 47 ... Depression 100 ... Continuous casting and rolling device Di: Depression diameter De: Depression depth

Claims (2)

[Claims] 1. A continuous casting and rolling apparatus comprising: a casting rolling machine main body for casting and rolling a molten metal to form a cast plate; and a molten metal supply nozzle for supplying the molten metal to the casting rolling mill main body. A continuous casting and rolling device, wherein the size of the concave portion of the unevenness indicating the surface roughness of the inner surface is a size for preventing the intrusion of the molten metal. 2. A continuous casting and rolling apparatus comprising: a casting and rolling machine main body for casting and rolling a molten metal to form a cast plate; and a molten metal supply nozzle for supplying the molten metal to the casting and rolling mill main body. A continuous casting and rolling device, wherein the average surface roughness of the inner surface is set to 1.0 micron or more and 3.0 microns or less.