JPS635180B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing slip between a shell and a roller surface in twin mold roller solidification shell formation.

An outline of a conventionally known continuous casting equipment using twin mold rollers will be explained based on FIG. 1 is twin mold rollers approaching each other;
2 and 3 are pinch rollers and guide rollers that extend downward from directly below both rollers 1, and constitute a slab conveyance path; 4 is a tundish nozzle; and 5 is a roller 1.
It is a weir placed above.

In the above configuration, molten metal 6 is injected between both rollers 1 from nozzle 4 to form a solidified shell 7 (hereinafter referred to as shell), and both rollers 1 are rotated in the direction of arrow A to pull out slab 8. However, in the initial stage of casting, the liquid level of the molten metal 6 is not high enough, and the hydrostatic pressure of the molten metal that presses the shell 7 against the roller 1 is insufficient, and there is a risk that the shell 7 may slip on the roller 1.
There is also a risk that slips may occur due to a drop in the liquid level at the end of casting. Such slips not only result in uneven shell formation, but also cause mold roller wear and breakouts.

Therefore, the present invention provides a method for preventing slips between the shell and the roller surface in twin mold roller solidification shell formation that eliminates such problems. The upper surface of the weir is sealed, molten metal is injected into the weir, and gas is supplied into the weir to form a shell on the twin mold rollers using a predetermined gas pressure. According to this method, even if the liquid level of the molten metal is not high enough at the beginning of casting, the shell is pressed against the rollers by gas pressure, so the shell is Prevents roller slippage. Similarly, no slip occurs when the liquid level drops at the end of casting. Therefore, it is possible to eliminate inconveniences such as uneven shell formation caused by slipping of the shell.

Hereinafter, one embodiment of the present invention will be described based on FIG. 2. 9 is a sealing lid that seals the upper surface of the weir 5; 10;
is an indicator of the liquid level height of the molten metal 6, and in this embodiment, it is a float floating on the liquid surface and is connected to the guide 11 on the inner surface of the weir 5.
It has a structure that allows it to be moved up and down only by being supported by the tank, and can sense the height of the liquid level. 12 is an argon gas supply pump; 13 is an argon gas supply pipe whose one end is connected to the discharge port of the pump 12, and whose other end has a nozzle portion 13A passing through the upper part of the weir 5 and extending above the float 10; and 14, an argon gas supply pipe; The solenoid valve 15 interposed in the supply pipe 13 is a pressure switch disposed downstream of the solenoid valve 14 of the supply pipe 13.
When the pressure inside decreases and reaches the lower limit set value, or when the level of the molten metal decreases, the solenoid valve 14 is activated to increase the opening degree, and the pressure inside the supply pipe 13 increases. It is activated to reduce the opening degree of the solenoid valve 14 when the upper limit setting value is reached or the liquid level rises. 16 is a pilot circuit. 17 is an argon gas discharge pipe whose one end penetrates the weir 5 and opens into the weir 5; 18 is a pressure regulating valve interposed in the discharge pipe 17;
When the pressure inside rises to a predetermined value, it is opened.

In the above structure, the molten metal 6 is injected from the tundish nozzle 4 that penetrates the sealed storage 9, and the argon gas is supplied into the weir 5 via the supply pipe 13 by the pump 12 to form the mold on the twin mold roller 1. The shell 7 is pressed against the twin mold rollers at a predetermined pressure, which is the sum of the hydrostatic pressure of the molten metal and the gas pressure. In this state, the roller 1 is rotated in the direction of arrow A to pull out the slab 8. When the liquid level of the molten metal 6 falls below the required liquid level height, the float 10 also falls accordingly. As a result, the float 10 and the nozzle part 1
3A increases, the amount of argon gas injected from the nozzle part 13A toward the float 10 increases, the pressure in the supply pipe 13 decreases, the pressure switch 15 is activated, and the solenoid valve 14 is closed. The opening degree is increased, and the amount of argon gas supplied into the weir 5 via the supply pipe 13 increases. Therefore, despite the abnormally low liquid level, Ciel 7
is pressed against the roller 1 by the pressure of argon gas, and no slip occurs. Next, when the liquid level of the molten metal 6 rises, the float 10
Since the pressure also rises and approaches the nozzle portion 13A, the pressure inside the supply pipe 13 increases, the pressure switch 15 is turned off, and the opening degree of the solenoid valve 14 is reduced. Furthermore, when the pressure inside the weir 5 rises and exceeds the required value determined from the liquid level height and the pressure inside the weir, the pressure regulating valve 18 is opened and the argon gas inside the weir 5 is discharged via the discharge pipe 17. be done. Even at the end of casting, the same effect as described above is carried out, and no slip occurs.

As described above, according to the slip prevention method in twin mold roller solidification shell formation of the present invention, even when the liquid level of the molten metal is very low in the early stage of casting, the shell can be pressed against the roller by using gas pressure. This prevents slipping between the roller and the shell during casting, especially when the liquid level drops at the end of casting. In this way, casting is performed without the shell slipping, and various problems caused by slipping can be solved.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of continuous casting equipment using twin mold rollers, and FIG. 2 is a longitudinal sectional view showing an embodiment of the present invention. 1...Twin mold roller, 5...Weir, 6...
... Molten metal, 7 ... Shell, 8 ... Slab, 9 ... Sealing lid, 10 ... Float, 12 ... Argon gas supply pump, 14 ... Solenoid valve, 15 ... Pressure switch, 17 ... Argon gas Discharge pipe, 18...pressure adjustment valve.

Claims (1)

[Claims] 1. A weir is placed on the twin mold rollers that are close to each other, the upper surface of the weir is sealed, and molten metal is injected into the weir and gas is supplied into the space above the molten metal in the weir to form the weir on the twin mold rollers. The solidified shell formed by the twin mold roller is pressed against the twin mold roller under a predetermined pressure by the hydrostatic pressure and gas pressure of the molten metal, and the twin mold roller is rotated to pull out the slab. A method to prevent slips on the roller surface.