JPH02160143A - Graphite mold for horizontal continuous casting - Google Patents

Abstract

PURPOSE:To improve flatness of casting surface and casting velocity by arranging heat resistant and high heat conductive weir plate having penetrating hole at opening hole part in inlet side formed with graphite dies and graphite side pieces. CONSTITUTION:The boron nitride-made weir plate 7 is fastened and fixed from upper and lower sides with upper graphite die 41 and the lower graphite die 42 at the opening hole part in the inlet side of the graphite mold. In this weir plate 7, the prescribed pieces of the penetrating holes 8 penetrated to drawing direction are formed in a rank to longitudinal direction. Further, the prescribed length part from the inlet side is a little projected at upper and lower parts and the remaining length part is inserted between the upper graphite die 41 and the lower graphite die 42 and the weir plate is set at center part of the opening hole part in the inlet side as holding some interval from the graphite pieces 5 at both sides. By this method, uniform and quick cooled solidification is executed to the whole body and the casting velocity is improved, and genera tion of crack at edge part and casting defect can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a graphite mold used for horizontal continuous casting of copper, copper alloys, etc.

[Conventional technology]

Rolled metal materials are manufactured by stretching a rod-shaped cast material through rolling rolls or wire drawing dies for wire rods, and by rolling rolled material cast into plate shapes with rolling rolls for thin sheet materials.

Conventionally, horizontal continuous casting graphite molds for continuous casting of rolling steel or copper alloy plates, for example, 15 fins thick x 3QQ m wide, have been used to continuously cast horizontal continuous casting graphite molds with spaced apart and parallel graphite molds, as shown in Figures 3 and 4. Two square plate-shaped graphite dies 4 arranged above and below facing each other, two graphite side pieces 5 inserted along the entire length of both side edges between the two graphite dies 4, and two graphite dies 4. 4, and a back plate 2 to which the water-cooled copper molds 3 are fixed.
The inlet port 6 formed at one end by the two graphite dies 4 and the two graphite side pieces 5 of this graphite mold is covered with the refractory lining 1 of the insulating furnace (or holding furnace) for molten metal. It connects to an opening in the side wall.

Continuous casting of copper or copper alloy plates using such graphite molds is
The inlet side opening 6 formed at one end by the two graphite dies 4 and the two graphite side pieces 5 of the graphite mold described above is filled with steel or This is done by continuously flowing molten copper alloy and cooling and solidifying it inside the graphite die 4 and graphite side piece 5, and the casting material is intermittently drawn out in the direction of the arrow. The continuously cast copper or copper alloy plate is then rolled into a product with a predetermined shape.

However, in the conventional graphite mold described above, the heat of the molten metal is removed only through the graphite die 4 and the graphite side piece 5, except for the removal of heat from the steel or copper alloy plate itself to be cast, so the molten metal is cooled. The cooling may be slow, and the cooling may be uneven, resulting in slow solidification, especially in the center of the molten metal. Therefore, it is necessary to slow down the casting speed to accommodate this slow solidification, otherwise the drawn casting material will be overheated (red-hot state) in the center.
Otherwise, breakdown (pulling out in a molten state) occurred, making it impossible to operate. For this reason, with conventional graphite molds, the casting speed is limited to at most 100 to 200 min/min, which has the major drawback of low productivity.

Furthermore, in the conventional graphite mold, the distance between the upper graphite die 4° and the lower graphite die 4 is small and the thickness of the casting material is thin, so the graphite side piece 5 is directly cooled by the water-cooled copper mold 3. Both sides of the width of one opening (
The molten metal tends to solidify from the graphite side piece 5 side), and the molten metal is not uniformly cooled and solidified in the width direction. the result,
The smoothness of the casting surface of the cast material is impaired, and the solidification mark 10 appearing on the surface of the cast material becomes arcuate as shown in FIG. The arc of this solidification mark 10 swells in the pulling direction of the arrow as the casting speed increases.For example, when the casting material is a copper plate with a thickness of 15 mm x width of 300 mm (1), and the casting speed is 200 fins/min, the arc of The swelling had reached 50 seagulls.

However, in order to subject the cast material to cold rolling as described above, it is necessary to scrape off the solidification marks on the surface. Conventionally, removing the arc-shaped coagulation mark 10 required 0.7 to 1.0 millimeter of face cutting on one side, which had the drawback of reducing the yield of the material to be rolled.

Incidentally, it is also possible to insert several blind weirs in the form of small pieces into the inlet side opening 6 of the graphite die, but when the opening of the graphite die 4 is long in the width direction, these blind weirs are inserted between the upper graphite die 4 and the lower graphite die 4. This was provided to prevent the side graphite die 4 from deforming, and was completely unrelated to the cooling rate of the molten metal, the casting rate, etc.

[Problem to be solved by the invention]

In view of such conventional circumstances, the present invention provides a graphite mold for horizontal continuous casting that can improve the smoothness of the casting surface and increase productivity by increasing the casting speed and increasing the productivity by speeding up and making uniform the solidification of the molten metal. The purpose is to provide

[Means to solve the problem]

In order to achieve the above object, the present invention includes two rectangular plate-shaped graphite dies arranged parallel to each other with an interval, and two graphite dies inserted along the entire length of both side edges between the two graphite dies. The inlet side opening formed at one end by the two graphite dies and the two graphite side pieces is connected to the insulating furnace. In the graphite mold for horizontal continuous casting, which is connected to the opening of the graphite mold, a plurality of through holes are formed along the elongated direction in the entrance side opening formed by the two graphite dies and the two graphite side pieces. A weir plate made of a heat-resistant and highly thermally conductive material is spaced apart from the two graphite side pieces, and a plurality of through holes penetrate inside and outside of the inlet side opening to connect the two graphite side pieces. It is characterized by being installed so that they are lined up in the direction.

[Effect]

In the present invention, a heat-resistant and highly thermally conductive weir plate with through holes is provided at the inlet side opening formed by two graphite dies and two graphite side pieces, so that the inflowing molten metal can flow through the weir. While passing through the through holes of the plate, it is temporarily cooled by the weir plate. Moreover, since the weir plate is placed with a gap between it and the graphite side pieces in the center where solidification is slower than on both sides in the width direction, cooling in the center is particularly promoted by the weir plate, resulting in uniform cooling and solidification throughout. become As a result, the solidification zone 9 of the molten metal in the conventional graphite mold shown in the upper half of FIG.
On the other hand, in the graphite mold of the present invention equipped with the weir plate 7 shown in the lower half of the figure, the solidification zone 9 of the molten metal moves as a whole toward the inlet opening 6, including the center, so that The casting speed can also be increased, and in some cases, if the casting was performed under the same conditions as before, the solidification zone 92 would be the weir plate 7.
Since there is a possibility that casting defects may occur due to reaching the above-mentioned amount, the casting speed must be increased.

As the material of the weir plate that performs the primary cooling effect of the molten metal, graphite or boron nitride, which has high thermal conductivity and excellent heat resistance, is preferably used.

In addition, since the weir plate can be placed in the center of the opening on the inlet side, more molten metal is distributed to both sides in the width direction where cooling and solidification occurs earlier than in the center where the cooling and solidification of the molten metal is delayed. Cooling and solidification on both sides of the direction are relatively delayed.

Therefore, by appropriately selecting the sizes and positions of the weir plate and the through holes, together with the above-mentioned primary cooling effect, it is possible to cool the entire molten metal relatively uniformly. As a result, the smoothness of the casting surface is improved, and as shown in FIG. 6, the solidification mark 10 appearing on the surface of the casting material becomes a straight line substantially perpendicular and parallel to the drawing direction, regardless of the casting speed. This linear coagulation mark 10 is 0.5 on one side.
Since it can be removed with a small amount of space on the order of fi, it leads to an improvement in yield.

In addition, the size of the weir plate, the number and size of through holes, the aperture ratio, etc. will depend on the shape and thickness of the mold, the type of copper or copper alloy to be cast, the material of the weir plate, etc., depending on the cooling solidification of the molten metal. Select so that it is uniform and fast overall.

〔Example〕

Using a conventional graphite mold and the graphite mold of the present invention in which a weir plate was provided at the inlet side opening, the thickness was 151)
Continuous casting tests were conducted on pure copper plates.

The conventional graphite mold used is shown in FIGS. 3 and 4 and is as described above, so a detailed explanation will be omitted, but the square plate-shaped graphite die 4 has a width of 330 mm, a thickness of 30 mm, and a length of 25 mm.
Width 28 x Thickness 15 x Length 250 t along the entire length of both edges in the length direction between two graphite gooses 4.4
By inserting 15 ml graphite side pieces 5 inward from the side edges, the size of the opening is 15 m vertically x 3005 m wide.

On the other hand, as shown in FIGS. 1 and 2, the graphite mold of the present invention has a weir plate 7 made of boron nitride in the inlet opening 6 of the conventional graphite mold, and an upper graphite die 4° and a lower graphite mold. Dice 4
Tighten it from above and below to secure it. This weir plate 7 has a width of 262 x a thickness of 15 (height) x a length of 50 as in the pulling direction, and has seven 1Qss square through holes 8 in a horizontal row in the longitudinal (width) direction. It is formed. Furthermore, the length 10 dragon part protrudes vertically from the entrance side, and the remaining length is 4Qms.
The part is inserted between the upper graphite die 4 and the lower graphite die 4, and is placed at the center of the inlet side opening 6 at a distance of 34 cm from the graphite side pieces 5 on both sides. Therefore, in the graphite mold of the present invention, the aperture ratio of the inlet side opening 6 is 38% of that without the weir plate 7'.

Next, molten copper held at 1220 t:'' was continuously flowed from the heat retention furnace into the inlet side opening 6 of the conventional graphite mold and the graphite mold of the present invention described above to perform continuous casting of pure copper plates. .

As a result, with the conventional graphite mold, the optimum casting speed that does not cause overheating or breakdown of the pure copper plate is 150 M/min, and the resulting pure copper plate also had slight edge cracks.

In addition, on the surface of the obtained pure copper plate, as shown in Fig. 7, an arc-shaped solidified bone ridge of 10° appears that swells in the drawing direction as the casting speed increases, and the arc bulge increases as the casting speed increases. 15
01) It was about 30a at 1/min. In order to remove this arc-shaped coagulation mark 10, it was necessary to place 0.7 to 1.0 degrees on one side.

In contrast, with the graphite mold of the present invention, cooling solidification occurs uniformly and quickly throughout the mold, so the casting speed can be reduced to 420 m1)1.
/min, about three times the conventional rate, and there were no cracks in the ears or casting defects in other parts.

Furthermore, as shown in FIG. 6, the solidification marks on the surface of the pure copper plate also become straight lines parallel to each other at right angles to the drawing direction, regardless of the casting speed, and the removal of this straight solidification mark 10 is achieved by removing 0.000.
Only 5 fins of solidifying material were required, and the yield of pure copper sheets for cold rolling was significantly improved compared to conventional methods.

〔Effect of the invention〕

According to the present invention, it is possible to significantly increase the casting speed, which has been a major drawback in horizontal continuous casting of copper or copper alloys, thereby achieving a dramatic improvement in productivity. Furthermore,
The rapid and uniform cooling and solidification of the molten metal results in a fine casting structure, making it possible to obtain a cast material with a smooth cast surface, so the rolling stock required during subsequent rolling is less than before, improving material yield. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a cutaway side view of a specific example of a graphite mold according to the present invention, FIG. 2 is a cutaway front view of the graphite mold of the present invention shown in FIG. 1, and FIG. 3 is a cutaway side view of a conventional graphite mold. Figure 4 is a cutaway front view of the conventional graphite mold shown in Figure 3, and Figure 5 is a diagram for comparing and explaining the heat removal state between the conventional graphite mold (upper half) and the graphite mold of the present invention (lower half). A schematic cross-sectional view, FIG. 6 is an explanatory diagram of solidification marks of a cast material according to casting speed using the graphite mold of the present invention, and FIG. 7 is an explanatory diagram of solidification marks of a cast material according to casting speed using a conventional graphite mold. be. 1. Heat insulation furnace refractory lining 2. Back plate 3. Water-cooled copper mold 4. Graphite die 4. Upper graphite die 4. Lower graphite die 5. Graphite side piece 6. Inlet side opening.
7...Weir plate 8...Through hole 9.9...Coagulation zone 10.1
0 ... Coagulation mark applicant Sumitomo Metal Mining Co., Ltd.

Claims (1)

[Claims] (1) Two square plate-shaped graphite dies arranged parallel to each other at intervals, two graphite side pieces inserted along the entire length of both edges between the two graphite dies, and two graphite side pieces inserted along the entire length of both edges between the two graphite dies. It is equipped with a water-cooled copper mold placed on each outer surface of graphite dies, and the inlet side opening formed at one end by two graphite dies and two graphite side pieces is connected to the opening of a heat retention furnace. The graphite mold for casting is made of a heat-resistant and highly thermally conductive material with a plurality of through holes formed along the longitudinal direction at the entrance side opening formed by the two graphite dies and the two graphite side pieces. The weir plate was installed with an interval between the two graphite side pieces, and a plurality of through holes were lined up in the direction connecting the two graphite side pieces, communicating the inside and outside of the inlet side opening. Characteristic graphite mold for horizontal continuous casting.