JPH09108782A - Mold for continuous casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently obtain a cast block without causing entrapping of foreign material and core crack at the time of continuous casting by inserting a hollow-shaped sleeve in the inside of a molten metal receiver and a cooling mold. SOLUTION: A mold for continuous casting is composed of a water cooling mold 1, molten metal receiver 2 and a cylindrical sleeve 7 arranged at the inside thereof. For the material of the sleeve 7, a graphite, ceramics, etc., having lubricity to the cast block can be used. The molten metal 5 is introduced into the inner sleeve 7 through a descending tube 4 from a casting trough 3. In the inner part of the sleeve 7, the molten metal is cooled during movement, and started to solidify and the solidification proceeds toward the lower part to obtain the cast block 6. Further, the sleeve 7 has the structure which can simply set by being inserted from the molten metal receiver 2 side with the molten metal receiver 2 fixed to the cooling mold 1 so as to simplify the change of the sleeve even in the case the inner side surface of the sleeve 7 wears or damages by using the mold for long time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting mold having an effect of suppressing the occurrence of cracks on the surface of an ingot.

[0002]

2. Description of the Related Art A conventional continuous casting mold is generally arranged on a cooling mold 1 having a passage 1a through which cooling water flows, as shown in FIG. The molten metal (molten metal) is composed of a molten metal receiver 2 made of a refractory heat insulating material introduced from a downcomer pipe 3. here,
The molten metal 5 is introduced from the casting trough 3 through the descending pipe 4 into the molten metal receiver 2, and the ingot 6 cooled and solidified in the cooling mold 1 is continuously obtained. Carbon or the like may be added to the molten metal for the purpose of preventing oxidation.

[0003]

However, according to the conventional continuous casting mold, the molten metal 5 introduced by the downcomer pipe 4 may start to solidify to some extent in the vicinity of the boundary between the molten metal receiver 2 and the cooling mold 1. In many cases, as the casting progresses, solidified fragments generated or foreign substances such as added carbon are caught on the boundary between the molten metal receiver 2 and the cooling mold 1, and as a result, cracks are generated on the surface of the generated ingot or foreign substances are caught. There was a possibility that

[0004]

The object of the present invention is to solve the drawbacks of the prior art and to perform core cracking of an ingot that has no foreign matter entrained in the ingot during continuous casting and has a smooth surface. It is an object of the present invention to provide a continuous casting mold that can be efficiently obtained without causing such problems. In order to achieve the above object, the continuous casting mold of the present invention is a hollow-shaped molten metal receiver for receiving molten metal, and is continuously provided below the molten metal receiver, and a refrigerant for cooling the molten metal flows through the inside. It is composed of a hollow cooling mold and a hollow sleeve inserted inside the molten metal receiver and the cooling mold.

Here, the shapes of the molten metal receiver, the water-cooled mold and the sleeve may be cylindrical or polygonal hollow bodies depending on the shape of the ingot to be cast. The sleeve preferably has fine grooves in the portion corresponding to the molten metal receiver, and the grooves have a pitch of about 1 to 3 mm and about 0.2 to 2 m.
It is preferred to have a depth of m.

By inserting the sleeve inside the water-cooled mold and the molten metal receiver, the boundary between the water-cooled mold and the molten metal receiver as seen from the molten metal side is substantially eliminated, and the solidified pieces are formed near the boundary between the molten metal receiver and the water-cooled mold. Even if it occurs, cracks do not occur on the surface of the ingot to be generated, and foreign matter is less likely to be caught on the surface or inside of the ingot. Further, by forming fine grooves inside the sleeve portion corresponding to the molten metal receiver, the coefficient of heat transfer from the molten metal to the molten metal receiver is reduced, and the formation of solidified pieces in this portion is suppressed.

On the other hand, when the mold (the inner surface of the sleeve) is worn due to long-term use, it is possible to prevent the casting size from changing by replacing the sleeve.

[0008]

Embodiments of the present invention will be described below. FIG. 1 shows an embodiment of a continuous casting mold according to the present invention. Although the description of the parts overlapping with the prior art is omitted, from the water-cooled mold 1, the molten metal receiver 2 and the cylindrical sleeve 7 installed inside them. Become. As the material of the sleeve 7, graphite, ceramics, or the like having a slip property with respect to the ingot can be used, and the material can be changed according to the material to be cast.

The molten metal 5 is introduced into the inner cylinder 7 from the casting trough 3 through the downcomer pipe 4. Inside the sleeve 7, as the molten metal moves, it is cooled and begins to solidify, and further solidification proceeds downward to obtain the ingot 6. Here, on the outer side of the sleeve 7, there are the molten metal receiver 2 and the cooling mold 1, and the molten metal 5
Does not receive much cooling effect in the molten metal receiver 2,
The portion of the cooling mold 1 receives a strong cooling action.

The sleeve 7 is in a state in which the molten metal receiver 2 and the cooling mold 1 are installed so that the mold can be replaced easily even if the inner surface of the sleeve 7 is worn or damaged due to continuous use of the mold for a long time. It has a structure that can be easily installed by inserting it from the molten metal receiver 2 side. As a result of casting a billet having a diameter of 250 mm using the continuous casting mold of the present embodiment, the obtained ingot has a smooth surface casting surface, which is better than that of an ingot produced by a conventional mold. A good casting surface was obtained. Further, in the ingot produced by the mold of the present embodiment, the defect occurrence rate on the surface of the ingot was reduced to 1/5 or less as compared with the conventional ingot.

On the other hand, as shown in FIG.
Has fine grooves 8 on the inner surface of the portion corresponding to the molten metal receiver 2.
Can be provided. By forming the fine grooves 8, the surface tension action of the molten metal 5 works in the portion corresponding to the molten metal receiver 2, and the molten metal 5 does not directly contact the inside of the groove 8,
The contact portion between the molten metal 5 and the sleeve 7 is limited to the vicinity of the narrow protruding portion 9. Therefore, the area of contact between the sleeve 7 and the molten metal 5 is significantly reduced, and the heat transfer coefficient from the hot molten metal 5 to the sleeve 7 (the molten metal receiver 2) is reduced.

By reducing the heat transfer coefficient, the sleeve 7
It is possible to suppress the heat escaping to the molten metal receiver 2 (and hence the water-cooled mold 1) via the, and it is possible to improve the heat insulating effect of the molten metal receiver 2. However, if the groove 8 is made too large, the surface tension action of the molten metal 5 cannot be supported by the hydrostatic pressure, so that the contact area between the molten metal 5 and the sleeve 7 becomes large and the amount of heat transfer may increase. Therefore, in order to maintain the surface tension effect of the molten metal, it is necessary that the pitch of the grooves 8 is about 1 to 3 mm and the depth is about 0.2 to 2 mm.

By forming the groove 8, the amount of heat taken by the sleeve 7 from the molten metal 5 in the portion corresponding to the molten metal receiver 2 can be reduced, and the solidification start position can be moved further downstream from the molten metal surface (meniscus). To prevent carbon, which is used for the purpose of preventing oxidation, from getting caught in the surface of the molten metal, and to obtain the effect of a hot metal that is effective for desorption of gas generated from the molten metal during the cooling process and for core cracking. You can

[0014]

As described in detail above, according to the continuous casting mold of the present invention, a hollow shaped molten metal receiver for receiving molten metal and a continuous molten metal receiver are provided below the molten metal receiver to cool the molten metal inside. Since the cooling mold having a hollow shape in which the refrigerant flows through and the hollow sleeve inserted into the inside of the molten metal receiver and the cooling mold, foreign matter is not caught in the ingot during continuous casting. In addition, it is possible to efficiently obtain an ingot having a smooth casting surface without causing core cracks.

The present invention can be applied not only to semi-continuous casting but also to molding of synthetic resin such as plastic.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a continuous casting mold of the present invention.

FIG. 2 shows an example in which a groove is provided inside a sleeve used in the continuous casting mold of the present invention.

FIG. 3 shows an embodiment of a conventional continuous casting mold.

[Explanation of symbols]

 1 Cooling mold 2 Molten metal receiver 3 Cast gutter 4 Downcomer pipe 5 Molten metal 6 Ingot 7 Sleeve 8 Groove 9 Projection part

Claims (3)

[Claims] 1. A hollow-shaped molten metal receiver for receiving molten metal, a hollow-shaped cooling mold which is continuously provided below the molten metal receiver and through which a coolant for cooling the molten metal flows through, and the molten metal receiver. And a hollow sleeve inserted inside the cooling mold,
Continuous casting mold. 2. The continuous casting mold according to claim 1, wherein the sleeve has fine grooves in a portion corresponding to the molten metal receiver. 3. The grooves have a pitch of about 1 to 3 mm and a pitch of about 0.2.
The continuous casting mold according to claim 2, having a depth of ˜2 mm.