JP2540032B2 - Method for starting a continuous casting machine with multiple slabs - Google Patents

Abstract

1. A method for starting up a continuous casting system comprising a plurality of castings, especially for pouring molten steel from an intermediate vessel (3) into a plurality of continuous casting moulds (A, B, C) by means of adjustable gate valves (4), with a nominal filling level (8) of the melt being within a measuring zone (9) of a filling level gauge means (9, 10, 11) associated to each mould (A, B, C) and with the resultant castings being withdrawn from a castings withdrawing aggregate (12 through 15) at the same speed, characterized in that switching on of the castings withdrawing aggregate (12 through 15) after reaching a lower signal plane (21) within the measuring zone (9) is effected through the actual filling levels (20) of all moulds (A, B, C) or through the actual filling level (20) first reaching an upper signal level (22) disposed within the measuring zone (9), with the gate valves (4) of the moulds (A, B, C) whose actual filling level is still below the lower signal level (21), in the latter instance, being closed, and that each actual filling level (20), from the lower signal level (21) along a predetermined ascending curve (40) is adjusted into the nominal filling level (8).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a plurality of metal melts each supplied from an intermediate container having a controllable tapping device corresponding to the number of continuous casting molds. It relates to a method for starting a continuous casting machine with multiple castings, in which the filling level of the castings is monitored in a measuring zone and all the castings formed are drawn from the castings at the same speed by means of a common casting device.

[Conventional technology]

For such a method, Japanese Patent Application No. 60-188749 (Japanese Patent Application Laid-Open No. 61-18749
According to No. 67551), all the outlet closing devices of the intermediate container are completely opened to start casting, and the actual filling level in each mold is raised above the dummy cast head, and the actual filling level is measured. Squeeze the tap closure device belonging to the mold that reaches a predetermined lower signal surface in the interval so that all actual fill levels are the same or one of the actual fill levels is below the target fill level in the measurement interval When the predetermined upper signal surface is reached, the slab withdrawal drive is started. As a result, the operational safety of castings carried out at the same drawing speed is improved with relatively simple process steps.

However, in this method, at the start of casting, all the outlet closing devices of the intermediate container must be completely opened, and then the outlet closing devices belonging to each mold must be controlled so that all the molds have the same actual filling level. However, it has a drawback that the control of the outlet closing device is complicated and expensive.

[Problems to be Solved by the Invention]

The object of the invention is to further simplify the process steps and reduce the casting time.

[Means for solving the problem]

To solve this problem, according to the present invention, the actual filling level of all the molds reaches a predetermined lower signal surface in the measuring section, or the actual filling level of any one of the molds is predetermined. When the upper signal surface of the mold is reached, the slab withdrawal device is started, and the actual filling level of each mold is increased from the lower signal surface to the target above the upper signal surface along the melt surface rise curve with a predetermined slope. Control to reach fill level.

〔The invention's effect〕

Thus, according to the invention, it is possible to advantageously avoid a control in which the actual filling level of all the molds is the same, which also reduces the casting time. The slab withdrawal device starts when the actual filling level of all the molds and thus the last actual filling level exceeds the lower signal surface, or when the actual filling level of any one mold reaches the upper signal surface. To start. In this case, according to the present invention for safe casting in operation, the control of the actual filling level of each mold starting from the lower signal surface is performed up to the target filling level along the melt surface rising curve of a predetermined gradient, The molten metal is prevented from solidifying in the tap hole closing device, and the molten metal is prevented from overflowing beyond the mold edge.

〔Example〕

 The invention is explained below with reference to the drawings.

In FIG. 1, a ladle is designated by 1, from which a molten metal, for example molten steel, is passed through an adjustable tap closure device 2 and an intermediate container having three tap closure devices in the form of a sliding closure device 4. 3 is supplied. These tap opening closing devices 4 regulate the inflow of the molten metal into the continuous casting molds A, B and C through the injection pipe 5. For this purpose, each sliding closure 4 is mechanically connected to an actuating element 6 whose respective operating position is measured by a position measuring device 7. The free end of the injection tube 5 enters the mold A, B, C, the target filling level 8 set for its normal operation consists of a transmitter 10 and a receiver 11 belonging to each mold A, B, C. It is in the measuring section 9 of the filling level measuring device.

After the molds A, B, C, a secondary cooling device (not shown) for simplification, a drive roll 12, a pulling drive device 13, a pulling device having a drive adjuster 14 and a pulling speed measuring device 15,
It is commonly provided for the cast piece 18. The withdrawal speed measuring device 15 gives its measured value to the drive adjusting device 14 and the processor 16, which further measures the position measuring device 7 for monitoring the opening degree of the sliding closing device 4 and the filling level measuring devices 10, 11. The measurement value of the receiver 11 is received and processed. The data obtained reaches a control computer 17 which is integrated in the processor 16 and which sends appropriate control commands to the operating element 6 of the slide closing device 4 and the drive regulator 14 of the slab withdrawal drives 12-15. Give to. Here, the withdrawal speed is fixed as a constant,
That is, the cast pieces 18 formed in the molds A, B, and C are drawn out at a constant speed by the common drawing devices 12 to 15. This means that the target filling level 8 defined in the mold is adjusted by the sliding closure device 4 only from the inlet side. For this reason, the sliding closing device 4 is kept in its throttle position so that the molten metal surface reaches the target filling level 8 in a normal casting operation.

To start casting, the dummy cast piece 19 is put into the casting molds A, B and C, and the drawer driving device 13 is stopped. The measuring section 9 is provided with a predetermined lower signal surface 21 and an upper signal surface 22, which serve to control the slide closing device 4 and the slab withdrawal drive 13 for the start of casting.

According to the invention, first the sliding closure device 4 is preferably 35%.
Only opened, never fully opened. As a result, an adjustment allowance is created in the closing direction and the opening direction with respect to the sliding closing device 4, so that each actual filling level 20 that rises in the molds A, B, C is from the lower signal surface 21 to the target filling level 8. Allows rise along a predetermined melt surface rise curve 40 (Fig. 2). This melt surface rise curve 40 determines the filling rate of molds A, B and C.
Is lower than the solidification limit in the taphole closing device 4 based on the dimensions of the molds A, B and C, the parameters related to the structure such as the diameter of the injection pipe 5, and the parameters related to the actual operation such as the drawing speed of the cast piece 18. So that it is not so gradual, and is not steep enough to exceed the overflow limit of the molten metal that exceeds the edges of the molds A, B, and C when shifting to the adjustment of the target filling level 8.
It is experimentally obtained for each continuous casting machine.
The ascending curve 40 is adapted to the operating conditions of the casting machine by appropriate programming of the processor 16.

Each sliding closing device 4 performed according to the molten metal rise curve 40
The adjustment of the starting of the actual signal level 21 in the lower mold surface A, B, C in the corresponding mold A, B, C, as described above, is carried out at all actual filling levels and thus the last actual filling level A20 or B20. Alternatively, when C20 crosses the lower signal surface 21, the control computer 17 of the processor 16 activates the drawer drive 13 of the common drawer for the slab 18. The actual filling levels A20, B20, C20 then rise to the target filling level 8 which is set for normal casting operations, independently of each other and on the basis of the same criteria and thus the parallel rising curves 40 in the graph. Until done. If this transition to the target fill level 8 is subject to excessive impact due to the actual fill level 20 rising too fast, the melt may overflow beyond the mold edges. Therefore, when the actual filling level 20 of either mold A or B or C reaches the upper signal surface 22 at the start of casting, the drawer drive 13 is started. If another actual filling level is still below the lower signal surface 21, a closing command is issued to the sliding closing device 4 of this delayed actual filling level 20.

The graph according to FIG. 2 applies to the actual filling level 20 shown in FIG. According to it, the actual filling level 20 of the mold C is such that, after simultaneously squeezing and opening all the sliding closures 4 to start the casting, the lower signal surface 21 is first shown after a time Ct.
The sliding closing device 4 belonging to the mold C then adjusts the inflow of the molten metal according to the rising curve 40. Molds B and A
The actual filling level 20 of the signal plane 21
Through which the actual filling level is adjusted by curve 40. None of these actual fill levels 20 are too late. Since the filling level A20 reaches the lower signal surface 21 before the filling level C20 reaches the upper signal surface 22, the start command to the slab drawing drive device 13 is actually the filling level A2.
Get out of 0.

In the example according to FIG. 3, in contrast to this, the actual filling level A20 reaches the upper signal surface 22 and the actual filling level B20 exceeds the lower signal surface 21, but the actual filling level C20 lags behind. Below the side signal surface 21. In this condition of the actual filling level, the slab withdrawal drive 13 is activated on the upper signal surface 22 by the actual filling level A20, while at the same time the sliding closure device 4 of the actual filling level C20, which does not exceed the lower signal surface 21, is described above. To be closed.

[Brief description of drawings]

FIG. 1 is a schematic view of a continuous casting apparatus in a casting start position, and FIGS. 2 and 3 are graphs showing two possible casting start processes. 8 …… Target filling level, 9 …… Measuring interval, 12 to 15 …… Slab extraction device, 20 …… Actual filling level, 21 …… Lower signal surface, 22 …… Upper signal surface, 40 …… Melting surface Ascending curve

Claims (1)

(57) [Claims] 1. Forming by monitoring the filling level of a plurality of molds each of which is supplied with molten metal from an intermediate container having a controllable tapping device corresponding to the number of continuous casting molds in a measuring section. In the starting method of the continuous casting apparatus, in which all the cast pieces are drawn from the mold at the same speed by the common cast piece drawing apparatus, the actual filling level (20) of all the molds (A, B, C) is measured in the measurement section (9 Prescribed lower signal surface in ()
Or the actual filling level (20) of any one of the molds reaches a predetermined upper signal surface (22) in the measuring section (9), activates the billet withdrawing device (12-15), Moreover, the actual filling level (20) of each mold (A, B, C) is higher than the upper signal surface (22) along the molten metal surface rising curve (40) with a predetermined gradient from the lower signal surface (21). A method for starting a continuous casting apparatus having a plurality of slabs, characterized by controlling to reach a target filling level (8).