JPH07227647A - Production of long sized aluminum cast block - Google Patents

Abstract

PURPOSE:To obtain a cast block for rolled plate having good appearance and quality without any oxide by pouring molten aluminum on a moving thin plate, irradiating this contact boundary part with high energy density beam to cause wetting condition. CONSTITUTION:The aluminum thin plate 1 is passed through the range of a molten metal holding frame 2, 2' in contact with the plate width direction, and the molten aluminum 3 is poured onto the thin plate 1 so as to obtain a prescribed thickness. The molten metal surface 4 is sealed by flowing gaseous argon 5. At the same time, the oxide on the surface is removed and the molten metal 3 and the thin plate 1 are integrated by TIG arc 7 at the contact boundary part 6 between the molten metal 3 and the thin plate 1 in the reverse direction to the shifting direction. Further, cooling water 8 is jetted to the back side of the thin plate 1 to forcedly cool the thin plate. To the long cast plate obtd. in such a way, the ordinary hot-rolling and cold-rolling are executed as it is and the aluminum sheet having the desirable thickness can be obtd.

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 ingots for aluminum and aluminum alloy rolled sheets with high efficiency, low cost and high quality. In the present specification, aluminum means pure aluminum and aluminum alloy.

[0002]

2. Description of the Related Art Generally, an aluminum plate is manufactured by repeatedly rolling an ultra-thick ingot many times to obtain a thin plate.
In order to increase the production efficiency of the method of obtaining this thin plate, a method of casting the molten metal directly into the shape of a thin plate is known, but since the molten metal is brought into direct contact with a cooling roll or the like to forcibly cool it, the solidified surface is flawed or coarse. There has been a problem that surface defects such as an oxide film are formed, which cause deterioration of the quality of the plate surface in the subsequent rolling, finishing and surface treatment processes.

On the other hand, the inventor of the present invention surrounds the four circumferences with a thin plate, injects the molten metal into it, and wets the plate and the molten metal to integrate the plate and the molten metal to prevent problems such as molten metal leakage and interface defects. Then, a method of obtaining an ingot having excellent surface quality was proposed (Japanese Patent Laid-Open No. 3-81047). However, in this method, although an ingot with excellent surface quality is certainly obtained, it is necessary to secure a space for causing the wetting of the plate and the molten metal. As a result, the above problem of production efficiency has not been solved.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks and to provide a method for producing a long ingot with excellent inner surface and surface quality, high efficiency and low cost. .

[0005]

Means for Solving the Problems The essence of the present invention is to pour molten metal onto a horizontal thin plate which is moving at high speed under an inert gas shield and to treat the plate / molten interface to wet and solidify the molten metal and the plate. It is what makes me. That is, the present invention provides a molten metal holding frame in contact with both ends in the plate width direction on the plate surface in one area on a long aluminum thin plate that moves horizontally at high speed, while pouring aluminum molten metal on the moving thin plate, The contact boundary between the molten metal and the plate on the side opposite to the moving direction of the plate (upstream side) is irradiated with a high energy density beam to cause wetting of the molten metal and the plate, and in the moving direction of the plate (downstream side) This is a method for producing a long aluminum ingot, in which the surface is shielded with an inert gas and the back side of the thin plate is forcibly cooled at the same time.

A description will be given below with reference to the drawings. Figure 1
1A and 1B are schematic views showing the method of the present invention, FIG. 1A is a side view and FIG. 1B is a plan view, and a thick arrow indicates a moving direction of an aluminum thin plate.

Here, the speed at which the long aluminum thin plate moves horizontally at a high speed is determined by the wetting processing speed and the molten metal replenishment speed, and is not particularly limited, but it is possible to increase the efficiency and improve the productivity to obtain the productivity higher than that of the current DC method. For 10-100m
/ Min is preferred. The movement direction of the long aluminum thin plate may be slightly inclined as long as the molten metal contacts the thin plate and uniform solidification is performed. As for the size of the long aluminum thin plate, it is desirable that the plate thickness is as thin as possible in terms of cost,
Irradiation with a high energy density beam to cause wetting is normally 0.2 to 2 mm from the viewpoint of preventing damage such as holes.
Is desirable. The plate width and length are not particularly limited, and for example, a wide coil having a plate width of up to about 2000 mm can be preferably applied.

Further, the alloy composition of the aluminum thin plate and the molten metal is not particularly limited as long as it can produce a usual ingot. The combination of the thin plate and the molten metal may be the same alloy system or different alloy systems, and is not particularly limited. Further, it becomes possible to use an Al-Li alloy, which has been difficult to perform DC casting in the past, as an alloy for the molten metal.

The size (length, height) of the molten metal holding frame in contact with both ends in the plate width direction depends on the moving speed of the thin plate, the forced cooling speed and the molten metal injection amount, and is appropriately determined by experiments or the like. For example, length 1m height 30mm
The above can be preferably applied. As a material for the molten metal holding frame, a material obtained by cooling a metal such as copper or aluminum with water, or a ceramic product such as a refractory can be used.
Alternatively, gas may be ejected from the surface of the molten metal holding frame so that the molten metal and the aluminum thin plate can smoothly come into contact with each other.

The inlet of the molten aluminum is 1 in the width direction of the plate.
The location is not limited to multiple locations, and multiple locations may be used. The injection amount depends on the area in the longitudinal direction of the molten metal holding frame and other operating conditions, but 100 kg / min is preferably applicable.

Ar, He, N ₂ or the like is preferably applied as the kind of the non-oxidizing inert gas that shields the surface of the molten metal. The temperature of the gas at this time may be room temperature or low temperature. The flow rate of the gas is not particularly limited as long as it can shield the surface of the molten metal and prevent oxidation, but is preferably about 10 liters / minute · cm ² .

The boundary between the tip of the molten metal and the plate, which is formed by flowing in the direction opposite to the moving direction of the plate, is determined by the balance between the molten metal injection amount, the moving speed of the plate and the viscosity of the molten metal. Therefore, it is necessary to control these amounts in order to maintain an appropriate plate thickness and prevent the molten metal from leaking upstream. Alternatively, as another control method, the control can be performed by providing orthogonal holding frames that are orthogonal to the holding frames at both ends and extend over the entire plate width, and change the gap between the orthogonal holding frames and the plate surface.

The type of high energy density beam source for irradiating the contact boundary between the molten metal and the plate is not particularly limited, but an AC or DC TIG arc, a plasma arc, a laser beam or the like can be used. One or more high energy density beam sources are used depending on the plate width. Further, the high energy density beam source may be oscillated in the plate width direction. The beam irradiation direction is preferably substantially parallel to the moving direction of the aluminum thin plate and obliquely from above. The type of arc can be a sine wave, a thyristor, a transistor, or an inverter. The laser is preferably a YAG or CO ₂ laser. The AC and DC TIG arcs or AC plasma arcs may be ignited not only to the extent of arc cleaning in the vicinity of the boundary line between the thin plate and the molten metal but also to the extent of melting the pole surface layer of the thin plate. It is preferable to discharge an inert gas from above the arc or laser beam to shield the aluminum thin plate and the surface of the molten metal.

The method for forcibly cooling the back side of the plate is not particularly limited, but air cooling, water cooling, or spray cooling with a mist-like water / air mixed gas can be preferably applied. Further, it may be brought into contact with a water cooling jacket or a cooling roll.

The thickness of the ingot plate is not particularly limited, but it is usually 20 to 30 mm because it is not efficient if it is too thick.

The thus-obtained cast sheet may be subjected to hot finish rolling as it is under a high temperature condition of, for example, about 400 ° C. by controlling the cooling conditions, and may be directly shipped as a finished product, or wound on a coil and cold rolled. A product may be obtained through a normal process such as.

[0017]

The reason why the solidified plate excellent in surface and internal quality can be obtained by the present invention is considered as follows.

In terms of surface quality, according to the present invention, a thin plate having a good surface is arranged on one surface (lower surface), and the thin plate having a good surface is used as it is for a rough oxide film or the like found in ordinary ingots. This is because a good surface can be obtained without surface irregularities.

Since the horizontal solidification is continuously formed on the other surface (upper surface) under the inert gas shield, the surface oxide film becomes remarkably thinner than the ordinary ingot, and the surface flatness is also high. This is because a smooth product can be obtained.
Since the cooling at this time is mainly controlled by the strong cooling on the shield gas side of the upper surface on the thin plate side of the lower surface, the degree of solidification on the upper surface is small, and therefore the partial re-cooling on the surface accompanying the release of latent heat of solidification on the upper surface. It is considered that a smooth solidified surface can be obtained because no melting occurs.

Since the side surface is not protected by the aluminum thin plate and the gas shield is weak, the oxidation prevention is not sufficient. As a result, the surface quality is the same as that of the ingot produced by the usual manufacturing method, but the side surface portion is trimmed or the like. Since it is finally cut off, there is usually no problem.

Next, in the internal quality, the surface of the thin plate is forcibly cooled directly with water or the like to cause rapid solidification, and the thickness thereof is at most about 20 to 30 mm, so that the entire thickness direction is about 100 ° C./sec or more. It is considered that the high-speed solidification of (1) causes the crystallized substances and crystal grains to become fine and to become a high quality ingot.

If there is an oxide on the surface of the thin plate, wetting does not occur,
Therefore, they are not integrated. In order to solve this, in the present invention, the thin plate and the molten metal are irradiated with high density energy. The reason why the integrated wetting is possible is considered as follows. That is, when the TIG arc or plasma arc of the high-density energy source is ignited in the vicinity of the boundary line between the aluminum thin plate and the surface of the molten metal, the oxide film on the surface of the aluminum thin plate is destroyed by the cleaning action of the arc and shielded by the inert gas. Therefore, reoxidation is prevented and wetting occurs. Since it is important to contact the molten metal with the surface oxide film removed, it is more preferable to use a thin oxide film having the surface oxide film removed in advance by pickling or alkali washing. Further, since the laser has an extremely high energy density, it is possible to easily melt only the extreme surface layer of the aluminum thin plate, so that wetting can occur. However, when the energy density is excessively high or when the moving speed of the aluminum thin plate is slow, there is a risk of penetration, so it is advisable to set the energy density appropriately according to the operating conditions.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. JIS A1100 Aluminum plate width 2000
The molten metal holding frame 2, which is in contact with both ends in the plate width direction of the coil 1 having a thickness of 1 mm and a plate thickness of 1 mm at a speed of 30 m / min as shown in FIG.
JI at a temperature of 700 ° C when passing horizontally through the 2'region
While pouring the aluminum melt 3 of SA1100 composition onto the thin plate 1 so as to have a thickness of 10 mm, the surface 4 of the melt was shielded by flowing an argon gas 5. At the same time, the TIG arc 7 (current 250 A, voltage 2) is generated at the contact boundary portion 6 between the molten metal 3 and the thin plate 1 on the side opposite to the moving direction of the thin plate 1.
The surface oxide was removed at 0 V) and the molten metal 3 and the thin plate 1 were integrated. At this time, cooling water 8 was sprayed on the back side of the thin plate 1 to forcibly cool the thin plate 1 to a temperature of 400 ° C. The thus obtained long cast plate was directly subjected to ordinary hot rolling and cold rolling to obtain a plate having a plate thickness of 2 mm. No particular abnormality was observed on the surface of the plate during this rolling process. Further, this plate was subjected to alumite treatment and its alumite property was examined. As a result, the alumite property was good with no particular abnormality.

[0024]

[Effect] As can be seen from the above examples, according to the present invention,
It has become possible to manufacture ingots for aluminum and aluminum alloy rolled plates having no oxide and no flaws and having a good appearance quality, with high efficiency and low cost, and with high quality.

Further, as described above, the long cast plate produced by rapid solidification can increase the productivity, and since the medium plate is directly produced, the heating / rolling process can be saved. Therefore, the production can be performed with high efficiency and low cost. Become.

[Brief description of drawings]

FIG. 1 is a schematic view showing a cast state of the present invention, (A)
Is a side view and (B) is a plan view.

[Explanation of symbols]

1 ··· Aluminum thin plate 2 2 ′ ··· Molten metal holding frame 3 ······ Aluminum molten metal 4 ····· Molten metal surface 5/5 '··· Inert gas shield 6 ··· Aluminum thin plate / aluminum molten metal contact boundary Part 7: High energy density beam 8: Forced cooling water

Claims (1)

[Claims] 1. A molten metal holding frame in contact with both ends in the plate width direction on the plate surface is provided in one area on a long aluminum thin plate that moves horizontally at high speed, while pouring aluminum molten metal on the moving thin plate, The contact boundary between the molten metal and the plate on the side opposite to the moving direction of the plate (upstream side) is irradiated with a high energy density beam to cause wetting of the molten metal and the plate, and in the moving direction of the plate (downstream side) A method for producing a long aluminum ingot, the surface of which is shielded with an inert gas, and at the same time, the back side of the thin plate is forcibly cooled.