JPH09206907A - Secondary cooling method in vertical type semi-continuous casting for cast block having rectangular cross section - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the producing yield of a rectangular cast block by automatically controlling a spouting angle of spouted cooling water corresponding to the shape of the rectangular cast ingot with an angle changing plate and cooling the cast block. SOLUTION: The cast block 6 is cooled with the secondary cooling water 4 spouted from the secondary cooling water outlet 22 at the lower part of inside of a water cooling mold 2. At this time, the spouting angle of the secondary cooling water 4 is automatically changed corresponding to the size and the shape of the surface 63 of the obtd. rectangular cast block 6 with the angle changing plate 71 in a spouting angle changing device 7 to cool the cast block, and the cross sectional shape of the cast block is corrected to a target rectangular shape as near as possible to obtain a prescribed cross section. The angle of the angle changing plate 71 can be made to change with a roller 72 for sensing the shape of the cross section of the cast block by contacting with the cast block surface 63 and a curving arm 73 and a straight arm 74. Further, the roller 72, curving arm 73, straight arm 74 and the angle changing plate 71 are connected with supporting points 76, 78, 79 and the curving arm 73 is supported to a supporting plate 8 at the lower part of the mold with a supporting point 77.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to metals, particularly Al, A
In the vertical semi-continuous casting of rectangular ingots for rolling non-ferrous metals such as l alloy, Cu, Cu alloys, etc., the invention relates to an improvement of a secondary cooling method for making the rectangular ingots have a rectangular sectional shape as much as possible. It is a thing.

[0002]

2. Description of the Related Art Conventionally, metals such as Al, Al alloys, C
DC casting (direct chill casting) is widely used as a continuous casting method for a rectangular ingot for rolling non-ferrous metals such as u and Cu alloys. As shown in FIG. 6, the DC casting is performed by melting a molten copper from a copper-based, aluminum-based, or other metal water-cooled mold 2 of a rectangular shape through a molten metal gutter 1 and a molten metal injection cylinder 11 from above. Is poured in, the pedestal 5 is gradually lowered from the bottom of the mold, and the solidified metal ingot 6 is continuously taken out to obtain an ingot 6 of a predetermined length, which is known as semi-continuous casting. ing.

In the cooling of this DC casting, first, the molten metal 3 poured into the mold is primarily cooled by the inner wall of the water-cooled mold 2 to form a thin solidified shell on the surface of the ingot. As the casting further progresses, the ingot 6 is continuously drawn downward and cooled by the secondary cooling water 4 ejected from the lower part of the mold, and solidification proceeds to the inside of the ingot. In the ingot 6 in FIG. 6, 61 is a molten metal liquid phase,
62 is a solid phase and 63 is the surface of the ingot. The rectangular ingot for rolling which is manufactured by this DC casting is subjected to hot rolling by chamfering the upper and lower surfaces by 5 to 15 mm.

However, the shape of the ingot having a rectangular cross section, which is produced by DC casting, has a target rectangular shape (thickness) in the longitudinal and sectional directions of the ingot due to deterioration of the mold, uneven primary cooling conditions, and the like. It often doesn't. Particularly in the case of a large ingot, for example, thickness 500 mm x width 1500
In an Al alloy ingot of mm × 6000 mm, the thickness may be about 500 mm ± maximum 15 mm in the longitudinal direction and the cross-sectional direction of the ingot. Therefore, in the chamfering of the surface of the ingot before the hot rolling, the chamfering amount must be large, and there is a problem that the chamfering yield is deteriorated. Also,
In relation to this, when the surface layer of the ingot is left uncut,
Surface defects occur on the rolled plate during the rolling process.

[0005]

DISCLOSURE OF THE INVENTION The object of the present invention is to provide a vertical semi-continuous casting of a cross-section rectangular ingot for rolling a metal, especially a non-ferrous metal such as Al, Al alloy, Cu, Cu alloy. The object is to find an improved secondary cooling method so that the shape can be a target rectangle (thickness) as much as possible.

[0006]

In order to solve the above-mentioned problems, the invention of claim 1 injects molten metal from above into a rectangular water-cooled mold having an open bottom, and performs primary cooling by the mold and jet cooling of the lower part of the mold. The molten metal is solidified by secondary cooling with water, and the ingot is continuously taken out from the bottom of the mold. In vertical semi-continuous casting for rectangular ingot, corresponding to the shape of the rectangular ingot obtained, the jet cooling water Is a secondary cooling method in vertical semi-continuous casting for rectangular ingot with a cross section characterized by cooling the ingot by automatically controlling the ejection angle of the angle changing plate,

According to a second aspect of the present invention, the angle changing plate is a roller that is in contact with a side surface of a rectangular ingot having a rectangular cross section that is continuously taken out and detects a shape of the ingot, a curved arm and a straight line connected to the roller. The secondary cooling method in vertical semi-continuous casting for rectangular ingots having a rectangular cross section according to claim 1, wherein the angle can be changed by the arm.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A secondary cooling method for vertical semi-continuous casting according to the present invention will be described with reference to FIGS. FIG.
FIG. 4 is a front view of a device for changing the ejection angle of secondary cooling water for the lower part of the mold according to the present invention, showing the positional relationship between the device and the surface of the ingot. FIG. 2 is a left side view of the ejection angle changing device of FIG. FIG. 3 is an explanatory diagram showing the positional relationship between the ejection angle changing device and the surface of the ingot in the case of the target ingot thickness. FIG. 4 is an explanatory diagram showing the positional relationship between the ejection angle changing device and the ingot surface when the ingot thickness is thin. FIG. 5 is an explanatory view showing the positional relationship between the ejection angle changing device and the surface of the ingot when the thickness of the ingot is large.

According to the present invention, as shown in FIGS. 1 and 2, the ingot 6 is cooled by the secondary cooling water 4 ejected from the secondary cooling water outlet 22 at the lower inside of the water cooling mold 2. An angle changing plate 71 of the ejection angle changing device 7 for changing the ejection angle of the secondary cooling water 4
Then, it is automatically changed in accordance with the size and shape of the surface 63 of the obtained rectangular ingot 6 and cooled, and the cross-sectional shape of the ingot is corrected to a target rectangle (thickness) as much as possible and a predetermined cross section To get a rectangle. FIG. 1 and FIG. 2 show a mode of the present invention in which the angle changing plate 71 of the jet angle changing device 7 changes the jet angle of the secondary cooling water by a mechanical method. In FIGS. 1 and 2, an angle changing plate 71 is connected to the lower part of the mold at a fulcrum 75 so that the angle of this plate can be changed. The angle of the angle changing plate 71 is
It can be changed by a roller 72 which is in contact with the ingot surface 63 and senses the shape of the ingot cross section, a curved arm 73 connected to this roller, and a linear arm 74 connected to the curved arm. The roller, the curved arm, the linear arm, and the angle changing plate are connected at the fulcrums 76, 78, 79,
The curved arm is supported by a fulcrum 77 on a support plate 8 below the mold.

In FIG. 3, solidification shrinkage of the ingot is targeted by primary cooling in the mold. Therefore, when the target ingot thickness is obtained, the angle changing device 7 and the secondary cooling water 4 are jetted. The angle and the positional relationship of the surface 63 of the ingot 6 are shown. That is,
The secondary cooling water 4 hits the angle changing plate 71, but is bent at an angle similar to that of the angle changing plate 71 to cool the surface 63 of the ingot 6. The setting of the angle changing device 7 is not necessarily limited to the above, but in this example, the angle changing device 7 is set at this position.

In FIG. 4, the angle changing device 7 and the ejection angle of the secondary cooling water 4 and the surface 63 of the ingot 6 when the solidification shrinkage of the ingot is large due to the primary cooling in the mold and the thickness of the ingot is thin. Shows the positional relationship of. When the thickness of the ingot is thin, that is, when the solidification shrinkage is large due to the primary cooling in the mold, the thickness of the ingot becomes thin. In this state, the roller 72 is released and the angle changing plate 71 is opened by the pressure of the secondary cooling water, so that the secondary cooling water 4 hits the surface 63 of the ingot 6 downward. Since the thickness of the solidified shell of the ingot becomes thicker and stronger as the cooling position moves downward from the lower surface of the mold, solidification shrinkage is less likely to occur when the cooling position is in the downward direction, and solidification shrinkage occurs because the vicinity of the lower surface of the mold is not cooled. It does not happen, and as a result, the thickness of the ingot gradually increases.

On the other hand, FIG. 5 shows the angle changing device 7 and the ejection angle of the secondary cooling water 4 and the ingot 6 when the solidification shrinkage of the ingot is small and the ingot is thick due to the primary cooling in the mold. The positional relationship of the surface 63 is shown. When the thickness of the ingot is large, that is, when the solidification shrinkage is small in the primary cooling in the mold, the thickness of the ingot becomes thick. In this state, since the roller 72 is pushed down by the surface 63 of the ingot 6, the angle changing plate 71 is closed and the ejection angle of the secondary cooling water 4 is changed upward in the ingot 6. Therefore, since the vicinity of the lower surface of the mold where the solidified shell is thin is cooled, solidification shrinkage occurs, and as a result, the thickness of the ingot is reduced.

In the above, a mechanical method has been shown as a method of changing the jetting angle of the secondary cooling water with the angle changing plate. However, other methods, for example, the distance from the ingot surface is measured with a range finder, It is also possible to compare the signal with the target and drive the motor according to the result to change the angle of the angle changing plate.

By mounting a large number of the angle changing devices 7 independently in the circumferential direction of the mold, the jetting angle of the secondary cooling water is automatically controlled in each region in the circumferential direction of the mold and in the longitudinal direction of the ingot. Since the solidification shrinkage in the circumferential direction and the longitudinal direction of the ingot becomes uniform, the cross-sectional shape of the obtained ingot can be a desired predetermined rectangle (thickness).

[0015]

EXAMPLES The present invention will be described below based on examples. In the secondary cooling method according to the present invention shown in FIG. 1, the Al alloy 5182 (Al-4.5 wt% Mg-0.3 wt% Mn) is used.
Alloy) thickness 500 mm x width 1820 mm x length 800
An ingot having a rectangular section of 0 mm was cast. The thickness of the rectangular ingot obtained by casting as described above is 4 in the cross-sectional direction and the longitudinal direction.
It was 95 to 505 mm, and the surface of the ingot did not remain even after 10 mm was ground on each side based on the thick portion.

[0016]

[Comparative Example] In the conventional DC casting shown in FIG. 6, the thickness of 500 mm × width of Al alloy 5182 as in the Example 1820
An ingot having a rectangular cross section of mm × length 8000 mm was cast.
The thickness of the rectangular ingot obtained by casting as described above was 485 to 515 mm in the cross-sectional direction and the longitudinal direction, and when 10 mm was chamfered on each side based on the thick portion, the ingot surface partially remained. . Therefore, in order to perform chamfering so that the mold surface does not remain, it was necessary to chamfer about 18 mm on each side.

As is clear from the examples and comparative examples of the present invention, the rectangular ingot for rolling cross-section produced by the method of the present invention can reduce the amount of chamfering and improve the yield of the ingot. It turns out that it contributes greatly.

[0018]

As described in detail above, the secondary cooling method for vertical semi-continuous casting for rectangular ingots of the present invention has a low equipment cost, is easy to manage, and has a desired cross section. Since the rectangular ingot can be formed, the manufacturing yield of the rectangular ingot can be remarkably improved, and the industrially remarkable effect is achieved.

[Brief description of drawings]

FIG. 1 is a front view of a device for changing a jet angle of secondary cooling water for a lower part of a mold according to the present invention, showing a positional relationship between the device and a surface of an ingot.

2 is a left side view of the ejection angle changing device of FIG. 1. FIG.

FIG. 3 is an explanatory view showing the positional relationship between the ejection angle changing device and the ingot surface when the ingot thickness is set to a target thickness.

FIG. 4 is an explanatory view showing the positional relationship between the ejection angle changing device and the ingot surface when the ingot thickness is thin.

FIG. 5 is an explanatory view showing the positional relationship between the ejection angle changing device and the surface of the ingot when the thickness of the ingot is large.

FIG. 6 is an explanatory view of a conventional DC casting for producing a rectangular ingot having a cross section.

[Explanation of symbols]

 1 Molten Gutter 11 Molten Injection Cylinder 2 Mold 21 Primary Cooling Water Passage 22 Secondary Cooling Water Outlet 3 Molten 4 Secondary Cooling Water 5 Ingot Cradle 6 Ingot 61 Liquid Molten Phase 62 Molten Solid Phase 63 Ingot Surface 7 Secondary Cooling water jetting angle changing device 71 Angle changing plate 72 Roller 73 Curved arm 74 Linear arm 75-79 Support point 8 Mounting plate for jetting angle changing device

Claims (2)

[Claims] 1. A molten metal is solidified by injecting molten metal from above into a rectangular water-cooled mold having an open bottom and secondary cooling by jet cooling water at the bottom of the mold to solidify molten metal from the bottom of the mold. In vertical semi-continuous casting for rectangular ingots that are continuously taken out, in response to the shape of the rectangular ingot obtained, the jet angle of the jet cooling water is automatically controlled by an angle changing plate to form an ingot. A secondary cooling method in vertical semi-continuous casting for rectangular ingots having a rectangular cross section, characterized by cooling. 2. The angle changing plate can be changed in angle by a roller for contacting a side surface of a rectangular ingot having a rectangular cross section continuously taken out to sense the shape of the ingot, and a curved arm and a linear arm connected to the roller. The secondary cooling method in vertical semi-continuous casting for rectangular ingots according to claim 1, wherein the secondary cooling method is used.