JPH02303655A - Graphite mold equipment for horizontal continuous casting of rectangular cross-section ingots - Google Patents

Abstract

PURPOSE:To make soundness of surface and inner structures in planar cast slab by providing a pushing lever for pushing a covering plate downward on the upper face of the upper steel sheet-made covering plate on the outlet side of the cast slab at the time of casting in a graphite mold device for horizontal continuous casting. CONSTITUTION:In the vicinity of the center part of the upper steel-made covering plate 3 at the outlet side of the cast slab in the graphite mold device for horizontal continuous casting, the pushing lever 16 for pushing the covering plate 3 at the time of casting is provided and by this pushing force, the center part of the upper graphite plate 1 in the graphite mold C is bent through the covering plate 3 and a water cooled copper block 2 at the time of casting to improve adhesiveness between the cast slab at this part and the mold C. By this mold, the development of gap between both caused by solidification of the cast slab is prevented and planar cast slab having sound surface and inner structures is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a graphite molding apparatus used for horizontal continuous casting of metals, particularly horizontal continuous casting of copper and copper alloy castings having a rectangular cross section.

(Prior art) Conventionally, in order to produce plate-shaped ingots of copper or copper alloy,
A graphite mold device for horizontal continuous casting is used, the structure of which is shown schematically in the figure.

That is, FIG. 2 is a side sectional view showing an outline of this type of conventional graphite molding apparatus, in which 1 is the top plate of the graphite mold;
indicates the upper and lower graphite plates forming the bottom plate, and the graphite mold C fixes these upper and lower graphite plates 1.1° and left and right side wall graphite plates (not shown) forming both side walls facing each other at a predetermined interval. By doing so, it forms a hollow body with both ends open so that one end forms a molten metal inlet and the other end forms an ingot outlet, and the shape of the hollow cross section is approximately the same size as the cross section of the plate-shaped ingot to be cast. It is configured to have a rectangular cross section.

2.2° is a pair of upper and lower water-cooled copper blocks that circumscribe the upper surface of the upper graphite plate 1 which forms the top plate of the graphite mold C, and the lower surface of the lower graphite plate 1° which forms the bottom plate, respectively, and the graphite mold C is inside thereof. A cooling water passageway (not shown) is provided for cooling the cast metal through the cooling water passageway. 3.3° is a pair of steel covering plates that respectively cover the upper and lower water-cooled copper blocks 2.2° to protect and reinforce them. The upper and lower graphite plates 1.1°, the graphite plates on both sides, the water-cooled copper block 2.2", and the steel cover plate 3.3° that make up these graphite molds are formed by the front and rear plates 4.5 and the upper and lower assembly plates 6.6°. They are assembled together to form a mold apparatus A, and one of the plates 5 is connected to the lining 9 of the molten metal holding furnace B through a heat insulating material 7 and a sealing material 8 so that the graphite mold C remains almost horizontal. 10 is a mold fixing plate.

The upper and lower graphite plates 1.1'', the upper and lower water-cooled copper blocks 2.2'', and the upper and lower steel cover plates 3.3'' in the molding device A are strongly tightened with a large number of through bolts (not shown), respectively, and the upper and lower graphite plates 1.1° and upper and lower water-cooled copper blocks 2.2° by increasing adhesion at each joint surface
．． It is configured to provide a good cooling effect to the cast metal through the 1° angle and to efficiently release the heat held by the molten metal 11 flowing into the mold from the molten metal holding furnace B to the outside of the system.

(Problems to be Solved by the Invention) Since the conventional graphite mold device for horizontal continuous casting is configured as described above, the molten metal 11 that flows into the mold from the molten metal inlet during casting is cooled and solidified in the mold. A solidification zone 12 is formed at an appropriate position in the mold, a plate-shaped ingot 13 with a cross section adapted to the cross-sectional shape of the mold is formed, and a continuous drawing device (not shown) is operated. The graphite mold C
A gap is generated between the upper graphite plate 1 and the upper surface of the ingot 13. The size of this gap varies depending on the type of metal to be cast, the size of the ingot, etc., but it increases toward the outlet of the ingot in the mold and toward the center of the chopping board-shaped ingot.

As a result, not only will the obtained plate-shaped ingot be undulated or surface oxidized, but depending on the type of alloy being cast, a vapor-deposited film of added alloying elements with high vapor pressure may adhere to the inner wall of the mold. This caused surface defects in the ingot and inhibited casting. In addition, due to the occurrence of such gaps, the cooling of the upper surface becomes significantly worse than that of the lower surface, causing a difference in the crystal structure between the upper and lower parts of the ingot as a whole, and the overall cooling capacity of the mold as a whole decreases. A problem also occurred in that casting productivity was significantly reduced.

The present invention aims to solve the above-mentioned problems inherent in the horizontal continuous casting method by actively increasing the cooling ability of the upper surface of the ingot when continuously casting plate-shaped ingots. .

(Means for Solving the Problems) That is, in the present invention, in the above-described conventional graphite mold device for horizontal continuous casting, a covering plate is placed near the center of the upper surface of the upper steel covering plate 3 on the ingot outlet side during casting. A pressing rod 16 that can be pushed downward is provided, and the pressing force of this rod causes the central portion of the upper graphite plate 1 of the graphite mold C to be bent downward through the steel cover plate 3 and the water-cooled copper block 2 during casting. The objective is to improve the adhesion between the lever part of the ingot and the mold, thereby achieving the above object.

(Function) Next, the outline of the structure and the function of the graphite mold device for horizontal continuous casting according to the present invention will be described.

FIG. 1 is a conceptual side sectional view of an apparatus shown for explaining the outline of the present invention. Note that the symbols shown in the drawings are the same as those shown in FIG. 2 except for those specific to the present invention.

As shown in FIG. 1, in the present invention, a seat 15 is provided at the center of the upper surface of the upper steel covering plate 3 on the ingot outlet side in the mold apparatus A, and is pressed into a screw hole formed in the upper assembly plate 6. I screwed in the rod 16 to receive it. For this purpose, the upper assembly plate 6 is made of a stronger material that is thicker than the lower one.

By forming it in this way, as the pressing rod 16 is screwed into the upper assembly plate 6, the upper steel covering plate 3
, the water-cooled copper block 2, and the upper graphite plate 1 is pressed downward near the ingot outlet, causing a deflection centering on this pressed part, and the lower graphite plate 1 at the deflected part.
Since the distance between the upper graphite plate 1 and the surface of the ingot 13 can be made small, even if the ingot shrinks, the adhesion between the upper graphite plate 1 and the surface of the ingot 13 can be ensured. However, the deflection deformation 1 is the pressure rod 16
It can be freely adjusted by adjusting the tightness.

The upper and lower graphite plates 1.1'' are fixed at their front and rear ends by front and rear plates 4.5, and at both sides in the width direction by sandwiching side wall graphite plates between the upper and lower graphite plates 1.1''. Therefore, even if a downward pressing force is applied to the center surface of the upper graphite plate 1 near the ingot outlet, the front, back, and both sides will not be deformed, and only the center will be deformed. Therefore, by relaxing the pressing force, it can be restored to its original shape.

In addition, the upper and lower graphite plates 1.1'', the water-cooled copper block 2.2'', and the steel covering plate 3.3'' are connected by passing through each with a through bolt 14 as before, but each member is connected by operating the pressing rod as described above. These members should be allowed to slide slightly within each joint surface, taking into account the displacement of the parts. Furthermore, since the cross-sectional shape of the mold at the molten metal inflow side opening is not allowed to be deformed in order to finish the cross-sectional shape of the ingot to be cast to a predetermined size, a distance piece 17 is inserted in this part. It is desirable to ensure the proper dimensions and shape.

In the graphite mold apparatus of the present invention, the upper graphite plate 1, the upper water-cooled copper block 2, and the upper steel cover plate 3, which are the main mold constituent members on the upper side, are designed so that they can be easily bent when the pressing rod 16 is operated. It is desirable that the thickness be the minimum necessary within the range that can satisfy each function. Further, when the width of the plate-shaped ingot 13 is extremely wide, a desired deformation can be achieved by providing a plurality of pressing rods 16 in the width direction on the upper surface of the mold outlet.

The structure of the molding apparatus A of the present invention other than the above is similar to the structure of the conventional apparatus shown in FIG. 2, and therefore the explanation thereof will be omitted.

<Example) Next, examples of the present invention will be described.

Thickness 15! l! When casting a plate-shaped continuous ingot of pure copper having a width of 300 rttm and a width of 300 rttm, in a horizontal continuous casting mold apparatus as shown in FIG. The length of the steel covering plate 3.2'' and the steel covering plate 3.3'' was set to 250++ m in the front-rear direction, and they were assembled in a predetermined position using the front and rear plates 4.5 and the assembly plate 6 to create a mold device A. The material of the graphite plate used for this is the same as the conventional one, and the thickness of both the upper and lower parts is 25 mm. The upper water-cooled copper block 2 was slightly thinner than the lower one, with a thickness of 40 mm, and was provided with cooling water passages (not shown) inside as in the prior art. The upper steel covering plate 3 had a thickness of 12 mm. This is the bottom one, about 1
75 mm thick.

These three upper members were firmly connected with a plurality of through bolts 14. In addition, the molten metal inlet of the graphite mold C has a height approximately corresponding to the thickness of the plate-shaped ingot to be cast, and a distance spacer 17 whose shape does not hinder the flow of the molten metal. inserted. Further, side wall graphite plates (not shown) were sandwiched on both sides of the upper and lower graphite plates 1.1'' at intervals corresponding to the width of the ingot, and were firmly connected to the upper and lower graphite plates with bolts.

Next, the front and rear plates 4.5 and the upper and lower assembly plates 6
．． After assembling the upper and lower three members in a predetermined position using a 6° angle, the press rod 16 is inserted into the seat 15 provided at a predetermined position on the upper steel cover plate 3 through a screw hole previously made in the assembly plate 6. It was set so that the tip was placed on the holder.

After the molding device A, which has been assembled in this way, is attached to the lining part 9 of the molten metal holding furnace B via the sealing material 8, a series of predetermined preparatory work such as preheating the heat insulating material 7 near the molten metal introduction part with a burner is carried out. The preparation for starting casting was completed. 'Next, pure copper molten metal melted at 1200°C was charged into molten metal holding furnace B, and casting was started. The casting start procedure is not particularly different from the conventional method. When the cast plate-shaped ingot was drawn out, a gap of 0.25 mm was created near the center of the plate width between the ingot-shaped surface at the ingot outlet and the upper graphite plate. Therefore, the press rod 16 was tightened to press the upper steel cover plate 3, and the upper graphite plate 1 near the ingot outlet was slightly bent and deformed so as to eliminate this gap. At this time, the tightening operation was adjusted to avoid excessive tightening and the pull-out resistance becoming too large.

The average casting speed during casting was 280 rtrm/min, and the surface condition of the plate-shaped ingots obtained was good, and the results of microstructural examination showed that the upper and lower columnar crystals had grown to approximately the same length. It was confirmed that there was no difference in cooling between the top and bottom of the ingot.

(Effects of the Invention) As described above, according to the present invention, the gap between the ingot surface and the mold inner wall at the upper part of the mold due to the shrinkage of the ingot during casting, which was a problem peculiar to the conventional horizontal continuous casting of plate-shaped ingots. Since the occurrence of gaps can be prevented, plate-shaped ingots with a healthy surface and internal structure can always be obtained, and the mold cooling capacity is also relatively increased, making it possible to further improve ingot productivity. This invention has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a conceptual side sectional view showing one embodiment of the graphite mold device for horizontal continuous casting of the present invention, and FIG. 2 is a conceptual side sectional view of a conventional graphite mold device for horizontal continuous casting. 1... Upper graphite plate, 1°... Lower graphite plate, Death... Upper water-cooled copper block, 2'... Lower water-cooled copper block, 3
... Upper steel covering plate, 3'... Lower steel covering plate, 4
...Front plate, 5...Rear plate, 6...
Assembly plate, 7... Heat insulating material, 8... Sealing material, 9... Lining, 10... Mold fixing plate, 11... Molten metal, 12... Solidification zone, 13...
Ingot, 14...Connection bolt, 15...Socket, 16.
...Press plate, 17...Distance piece, A...
Mold device, B... Molten metal holding furnace, C... Graphite mold Patent applicant Sumitomo Metal Mining Co., Ltd. Figure 2

Claims (2)

[Claims] (1) A horizontal graphite mold with openings on the molten metal inlet side and ingot outlet side and a rectangular hollow cross section that is almost the same as the ingot cross section, and a cooling mold that circumscribes the upper and lower surfaces of the graphite mold. In a graphite molding device that integrally combines a pair of upper and lower water-cooled copper blocks to protect the water-cooled copper blocks and a pair of upper and lower steel sheathing plates for reinforcing and protecting the water-cooled copper blocks, the ingot outlet side of the upper steel sheathing plate A graphite mold for horizontal continuous casting of a rectangular cross-section ingot, the upper surface of which is provided with a pressing rod capable of pressing the covering plate downward during casting. (2) The graphite mold apparatus for horizontal continuous casting of rectangular cross-section ingots according to claim 1, wherein a spacing piece is inserted into the hollow part on the molten metal inlet side of the mold.