SU876272A2 - Mechanism for continuous casting of billets - Google Patents

Description

one

The invention relates to metallurgy and can be used to obtain blanks in continuous casting plants. G

According to the main author. St. i 770650 a device for continuous casting of blanks is known, consisting of a refractory casting vessel and fixed on its side wall Q crystallizer and bottom drain channel and inductor.

In this case, the inductors are located along the perimeter of the casting container for its entire height in alternating rows, 15 in increments of 1.0-1.3 times the thickness of the side wall of the casting container. The mold is mounted in the side wall of the casting tank at a distance from its bottom equal to 2.0-2.5 20 of the internal diameter of the casting tank.

A disadvantage of the known device is that as a result of the supply of hot metal-25 la to the ingot crystallizer, an axial segregation develops in the central zone of the ingot, the resulting structure of the cast metal is coarse-grained, and low casting speed leads to low productivity.

Duration of continuous casting machine.

The purpose of the invention is to provide a low-grain structure of the blanks and increase the productivity of the device.

This goal is achieved by the fact that in a device containing a refractory casting tank with a crystallization fixed in its side wall and a bottom drain channel and inductors located along the perimeter of the casting machine for its entire height in alternating rows with a step equal to 1.0-1, 3 thickness of the side wall of the casting tank, and the mold, while mounted in the side wall of the casting tank at a distance from its bottom equal to 2.0-2.5 of the internal diameter of the casting tank, additionally in the lining of refractory PC13LIVO At the side of the inductors, the refrigerators are made of non-magnetic material, placed around the circumference of the tank in steps equal to two to three times the pitch of the inductors.

Reducing the pitch of the refrigerators to less than twice the pitch of the inductors leads to the creation of a continuous metal skull on the inner surface of the container, which will require a large power of the inductors to heat it up and retard at the end of the spill.

Increasing the spacing of the holo, the dilators more than three times the pitch of the inductors is accompanied by a decrease in the number of cooling etor inoles created in the form of crystals washed from the surface of the skull, and consequently, the full positive effect on crushing the structure and reducing segregation in the cast metal is not achieved and the machine does not increase continuous performance. pour.

FIG. 1 shows a device for continuous casting of blanks; general view; figure 2 - section aa in figure 1.

The device consists of a lined ferroelectric casting tank 1, closed by a lid 2, equipped with a funnel 3. The refractory tank, along its entire height, covers inductors 4 fed by a low-frequency current (2-5 Hz) and inductors 5 fed by an increased-frequency current (25-50 Hz) alternately arranged in rows with a pitch equal to 1.0-1.3 thicknesses of the side wall of the casting tank. At the lower level of the casting tank filled with liquid metal, a heated drain channel 7 is made to discharge contaminated metal into the mold 8. The heated drain channel can be closed for a starting period with a refractory stopper 9. In the side wall of the pouring tank 1 there is a mold 10 mounted above the bottom a part equal to 2.02, 5 of the inner diameter of the casting tank 1, made, for example, of boron nitride bound by silica. The part of the mold placed in the lining is not cooled; on the contrary, around this part an electric heater 11 is mounted in the lining of the pouring tank 1. The part of the mold protruding from the lining is cooled, for example, by running water. The preform 12 forming in the crystallizer is pulled out by the rollers 13 through the secondary cooling zones 14. The device also has a heater 15 for maintaining a high temperature of the walls of the drain channel 7 so that the outgoing contaminated metal does not freeze. Liquid metal is fed through the funnel 3 by a stream 16. To create crystallization centers in the lining of the refractory casting bottle, bones from the inductors 4 (5) water-cooled refrigerators 17 are installed in the form of welded boxes of non-magnetic material placed around the circumference of the tank in increments equal to two to three times step placement of inductors.

The operation is carried out by the device as follows.

Before pouring the metal into the chillers 1 and 17, running water is supplied and the pouring tank 1 is started to be heated by a burner up to 1200 s. This includes a heater 15 and 11, heating the lining of the casting tank at the point of entry of the mold and part of the mold 10, which is included in the lining of the casting machine. After the metal b of the casting tank has accumulated to the required height with the drain channel 7 closed, inductors 4 are supplied with a reduced frequency current (2-5 Hz) and inductors 5 fed with a higher frequency current (25-50 Hz) to rotate the metal layers in different directions . At the same time, the metal b, having acquired a rotational movement, mainly due to the effect of inductors 4 fed by a lower frequency current, rises along the inner wall of the casting tank 1. and completely covers the cavity of the mold 10, in which by this time a seed has been introduced (not shown) . The main mass of the metal rotates in one direction and only the surface layer of the metal slows down and remains stationary under the influence of inductors 5 fed by a current of increased frequency. At the same time, in the areas of the internal cavity of the casting tank 1, located against the coolers 17, skullcaps 18, from which the rotating metal washes away the crystals, which are the crystallization centers, and the overheating of the metal is removed, are frozen.

The part of the metal thus treated, entering the crystallizer, hardens faster with the formation of the fine-crystalline structure of the cast metal, which is practically devoid of segregation of individual elements. In this case, the extent of the liquid well is reduced by 30%, which in turn leads to an increase in the casting speed also by 30%. Reducing the duration of the casting leads to a decrease in the presence of metal in the smelting unit, reducing fuel consumption and refractories, in particular, by reducing the required overheating of the metal in the furnace.

Claims (1)

During continuous casting with rollers 13, the seed is first pulled out, and behind it, and the workpiece 12. When this is done, the workpiece is continuously thrown into the casting tank through the funnel 3 with a stream 16 on the side surface of the formed metal parabloid. In this way, a predetermined level of metal in the casting tank 1 is maintained. When the continuous casting process is established with a refractory stopper 9, the drain channel 7 is opened to drain the contaminated metal into form 8. By controlling the speed of rotation of the metal, a parabloid of such shape is created, in which the bottom of the pouring tank is exposed and The contaminated metal flows along the side surfaces of the drain channel. Here, the release of the contaminated metal is carried out continuously or periodically. In the case of periodic discharge of contaminated metal, the duration of the expiration of it from the discharge channel is established empirically. At the exit of the mold 10, the workpiece 12 is subjected to secondary cooling 14. Near the mold 10, refrigerators 17 are absent, and even opposite, to avoid spreading around the entrance to the mold 10, the electric heater 11 is continuously switched on. The thickness of the wall layer is regulated by changing the power of the inductors 5 fed by the increased current. frequencies. The size of the skull layer is controlled by the speed of rotation of the electromagnetic field generated by inductors 4 fed by a low-frequency current, as well as by adjusting the power of the inductors b fed by a high-frequency current. As the workpiece is pulled out of; mold cut it into measured pieces outside of the pulling rolls. Before the completion of the casting, the last portions of the metal in the casting capacity are rotated at elevated speeds, and the inductors 5, powered by a current of increased frequency, turn on a maximum speed to melt the crust. After the casting is finished, the rest of the contaminated metal is discharged from the casting tank through the drain channel into the mold. The implementation of the proposed device ensures the production of continuously cast billets with a dense fine-grained structure and with minimal segregation of harmful impurities in all zones of the ingot section. In addition, the casting rate is increased by 30%. The invention The device for continuous casting of billets according to ed.St. USSR No. 770650, characterized in that, in order to obtain a fine-grained structure of the workpieces and improve the performance of the device, refrigerated refrigerators made of non-magnetic material are placed in the lining of the refractory casting tank on the inductors side, arranged around the circumference of the tank with inductors. Sources of information taken into account in the examination 1. USSR author's certificate I 770650, cl. In 22 13 11/00, 1978.