KR20030017025A - Cooling system of mold and cast in the electromagnetic casting - Google Patents

Abstract

PURPOSE: A cooling system of mold and slab in electromagnetic casting is provided to prevent deformation of slab due to cooling shortage of mold using spray type coil and prevent cold crack of slab due to overcooling of slab using slab wiper. CONSTITUTION: In a continuous electromagnetic casting machine, the cooling system of mold and slab in electromagnetic casting is characterized in that first cooling spray(16) sprays cooling water(17) onto the mold(11) from the outside of the mold(11), a plural holes having a certain size are perforated on the inner surface of a spray type coil(12) differently from the mold(11) with the holes being spaced apart from each other in a certain distance, and slab coming out of the mold(11) is cooled by second cooling spray(18), wherein a plural holes having diameter of 0.5 to 1 mm are drilled on the inner surface of the coil(12) with the holes being spaced apart from each other in a distance of 5 to 30 mm, and the cooling system of mold and slab in electromagnetic casting comprises a wiper(19) that is installed at position of depth of non-solidified melt to remove cooling water that is flown down after cooling slab by the second cooling spray(18).

Description

Cooling system of mold and cast in the electromagnetic casting

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic casting apparatus for continuously casting aluminum and alloys thereof, and particularly, to prevent deformation due to lack of mold cooling by using a spray-type coil and cold due to overcooling of the cast using a cast wiper. It relates to a mold and cast cooling apparatus in an electromagnetic casting that is suitable to prevent cold cracks.

In general, a conventional method of continuously casting aluminum is a direct chill casting (DC) method in which the molten metal is directly cooled and cast with a cold mold.

The cast slabs are rolled and used as the final product.

However, the cast steel cast by such a DC method has a problem that a lot of defects occur on the surface to eliminate the need for a step of scalping the surface 50 ~ 100mm to reduce the error rate and productivity.

In order to solve such a surface defect, there is a cast-free electromagnetic continuous casting (EMC) to cast a slab without a mold by applying an electromagnetic field.

Casting by the conventional casting-free electromagnetic continuous casting method can significantly reduce the surface defects of the cast steel.

However, this moldless electromagnetic continuous casting method has a disadvantage in that the molten metal is unstable and cannot be cast at high speed because the molten metal is maintained in the electromagnetic field without a mold.

In addition, there is a continuous contact electromagnetic continuous casting method that compensates for the shortcomings of the castingless electromagnetic continuous casting method.

In the conventional continuous contact electromagnetic continuous casting method, a coil is wound around an electromagnetic mold designed to penetrate an electromagnetic field when casting aluminum, and the contact pressure between the mold and the solidification cell is reduced by Joule heat and electromagnetic pressure in the molten metal. Eliminate the defect In addition, the casting speed can be increased to realize a casting-rolling direct connection process to improve product quality and productivity.

Cooling of the mold used in the continuous-contact electromagnetic continuous casting process includes cooling by processing a cooling water channel inside the mold and cooling by spraying cooling water from the outside of the mold by spraying.

Therefore, cooling by processing the cooling water channel inside the mold has a disadvantage in that mold processing is difficult and the peripheral device is complicated and expensive. Therefore, it is suitable to spray the cooling water by spraying from the outside of the mold, which is a simple structure.

Electromagnetic continuous casting has a coil around the mold, and the strength of the electromagnetic field is inversely proportional to the distance, so it is effective to narrow the gap between the mold and the coil. Due to the structure of the electromagnetic continuous casting device, a mold cooling device of the coil part is required.

Cast out of the mold is spray cooled in the secondary cooling zone.

However, in the conventional technique of spraying the coolant by spraying outside the mold, the secondary coolant flows down the cast steel, which is caused by overcooling of the cast steel when casting an aluminum hard alloy (eg AlCuMg, AlZnMgCu alloy). There was a problem that a cold crack such as an edge crack occurs.

Therefore, the present invention has been proposed to solve the conventional problems as described above, and an object of the present invention is to prevent deformation due to lack of mold cooling by using a coil of the spray method when continuously casting aluminum and its alloys, The present invention provides a mold and cast cooling device in an electromagnetic casting in which mold deformation is made small by narrowing a gap between a coil and a coil.

In addition, another object of the present invention is to provide a mold and cast cooling device in the electromagnetic casting that can prevent the cold crack due to overcooling of the cast by eliminating the defect of the cast due to overcooling of the cast in the secondary cooling stand using the cast wiper. There is.

In order to achieve the above object, the mold and cast cooling device in the electromagnetic casting according to an embodiment of the present invention,

In the electromagnetic continuous casting machine, the primary cooling spray 16 to spray the coolant 17 to the mold 11 from the outside of the mold 11, the coil 12 that is sprayed to the mold 11 is A plurality of holes of a predetermined size in the inner surface is drilled at regular intervals, characterized in that the cast piece exiting the mold 11 is made to be cooled by the secondary cooling spray (18).

1 is a conceptual diagram of a mold and cast cooling device in the electromagnetic casting according to the present invention,

2 is a conceptual view showing a state where the upper and lower coils of the mold are opened in the conventional electromagnetic casting.

Explanation of symbols on the main parts of the drawings

11: mold 12: coil

13: slit 14: molten metal

15: solidification cell 16: primary cooling spray

17: cooling water 18: secondary cooling spray

19: wiper

Hereinafter, an embodiment according to the present invention configured as described above, the technical spirit of the mold and cast cooling device in the electromagnetic casting will be described in detail with reference to the drawings.

1 is a conceptual diagram of a mold and cast cooling device in the electromagnetic casting according to the present invention, Figure 2 is a conceptual diagram showing the top and bottom of the mold mold in the electromagnetic casting.

As shown, in the electromagnetic continuous casting machine, the primary cooling spray 16 to spray the coolant 17 to the mold 11 from the outside of the mold 11, spraying the mold 11 In the coil 12 is a plurality of holes of a predetermined size in the inner surface is drilled at regular intervals, so that the cast piece exiting the mold 11 is cooled by the secondary cooling spray (18).

In the coil 12, a plurality of holes having a diameter of 0.5mm to 1mm in the inner surface is drilled at intervals of 5mm to 30mm.

In the above-described electromagnetic casting, the mold and the slab cooling apparatus install a wiper 19 at a position of uncondensed molten metal which cools the slab by the secondary cooling spray 18 and then removes the cooling water flowing down.

Reference numeral 13 is a slit, 14 is a molten metal, and 15 is a coagulation cell.

Referring to the accompanying drawings, the operation of the mold and the slab cooling apparatus in the electromagnetic casting according to the present invention configured as described above is as follows.

First is a conceptual diagram showing the principle of the electromagnetic continuous casting technology according to the present invention.

Thus, when a current is applied to the coil 12 around the mold 11 in which the slit is processed in the casting length direction, a magnetic field is induced in the mold divided by the slit 13, and the current is induced by the magnetic field.

This current generates an induction magnetic field B and a current J in the molten metal 14 inside the mold 11 through the slit 13. This induced current not only heats the melt but also interacts with the magnetic field to generate electromagnetic forces (F) in the molten metal.

This electromagnetic force F increases the curvature of the surface of the water in contact with the mold 11 and reduces the contact pressure between the solidification shell 15 and the mold 11. Joule heat is also concentrated on the surface of the molten metal so that defects due to solidification unevenness and quenching are not generated.

The electromagnetic continuous casting machine of the present invention is a method of cooling the mold 11 by installing a primary cooling spray 16 outside the mold 11.

The coil 12 is wound around the mold 11 so that cooling of this portion is only caused by the coolant 17 flowing from the upper part of the coil 12 into the gap between the mold 11 and the coil 12. .

In the electromagnetic continuous casting, since the intensity of the magnetic field guided to the mold 11 is inversely proportional to the distance between the mold 11 and the coil 12, the gap between the mold 11 and the coil 12 needs to be narrowed, which causes difficulty in cooling. . In particular, since this portion is not only the most amount of heat transferred from the molten metal 14 to the mold 11, but also the induced current is concentrated, mold deformation occurs if cooling is not performed properly.

Figure 2 shows the mold deformation mode when the cooling of the coil part mold in the electromagnetic continuous casting is insufficient. When the temperature of the coil part mold 11 rises, tensile stress is generated by thermal expansion, and the mold 11 of the upper and lower ends of the coil 12, which is a relatively low temperature, is subjected to shrinkage stress. Since the electromagnetic continuous casting mold has a slit 13, the mold 11 at the upper end and the lower end of the coil 12 is opened as shown in FIG. 2.

Thus, the cooling water 17 sprayed onto the mold 11 can penetrate into the mold 11 along this gap. In this case, the water in contact with the molten water is vaporized and boils, so the stability of the casting is a problem.

In order to solve this problem, in the present invention, a hole of 0.5-1 mm in diameter was drilled at intervals of 5 to 30 mm on the inner surface of the electromagnetic application coil 12 to produce a spray-type coil. When the current (4500 AT) was applied to the general coil in the state of no casting, the maximum temperature of the mold 11 was about 90 ° C, but the spray coil of the present invention was 40 ° C.

The cast slab exiting the mold 11 is cooled by the spray method in the secondary cooling spray 18. Secondary coolant flows down the slab, which causes cold cracking, such as edge cracks, due to overcooling of the slab during casting of aluminum hard alloys (eg AlCuMg, AlZnMgCu alloys). It is a factor that occurs. Cooling control can be controlled by spray injection volume, but cooling by the coolant flowing along the cast is problematic.

Therefore, in this invention, the wiper 19 which removes the flowing coolant was provided. The material is a soft material that does not generate scratches due to friction with the cast steel. If the wiper 19 is set too high, cast rupture may occur due to lack of cooling, and if it is low, cast defects such as cold cracks due to overcooling may occur, so proper positioning is necessary. In the present invention, it is installed in the position of the uncondensed molten metal depth, this position is changed depending on the casting conditions such as casting speed, cooling water amount, applied current.

As such, the present invention is to prevent deformation due to lack of mold cooling using a spray-type coil and to prevent cold cracks due to overcooling of the cast steel using a cast steel wiper.

Although the preferred embodiment of the present invention has been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments. Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

As described above, in the electromagnetic casting according to the present invention, the mold and slab cooling apparatus prevents deformation due to lack of mold cooling by using a spray-type coil when continuously casting aluminum and its alloys, and prevents the caster wiper. This prevents cold cracks caused by excessive cooling of the cast steel, thereby making it possible to stably cast.

Claims (3)

In the electromagnetic continuous casting machine, The primary cooling spray 16 to the outside of the mold 11 to spray the coolant 17 to the mold 11, the coil 12, which is sprayed to the mold 11 has a predetermined size on the inner surface A plurality of holes are drilled at regular intervals, the mold and cast cooling device in the electromagnetic casting, characterized in that the slab exiting the mold (11) is configured to be cooled by the secondary cooling spray (18). The method of claim 1, wherein the coil 12, Mold and cast cooling device in the electromagnetic casting, characterized in that a plurality of holes with a diameter of 0.5mm to 1mm in the inner surface by drilling at intervals of 5mm to 30mm. According to any one of claims 1 to 2, wherein the mold and cast cooling device in the electromagnetic casting, Cooling device by the secondary cooling spray (18) and then the wiper (19) for removing the cooling water flowing down is installed in the mold and cast cooling device in the electromagnetic casting, characterized in that configured in the position.