JPS63199058A - Method for controlling pinch rolls in continuous casting machine for round section cast billet - Google Patents

Abstract

PURPOSE:To restrain jumping of a dummy bar head and to prevent cutting-off between a cast billet and the dummy bar head by detaching pinch rolls from at least a part of dummy bar exclusive use body at the time of starting continuous casting of the round section cast billet. CONSTITUTION:The head 21 of the dummy bar 15 having six pieces of the dummy bar exclusive use bodies 20 mutually connected with by links 22-26 is inserted in a mold, and pouring of molten steel is started. When the solidified shell is formed in the mold, the pinch roll stands 11-14 are driven to draw the dummy bar 15 through the body 19 of the dummy bar 15. In this way, drawing of the cast billet 16 connected with the head 21 is started. And, when the exclusive use body 20 of the dummy bar 15 reaches to the first stand 11, this pinch rolls 18 are rolled to the exclusive use body 20 to drive this and after that, when a fourth link 25 passes through the pinch rolls 18, the pinch roll 18 is ascended, to detach from the exclusive use body 20. And, when a second link 23 passes through the pinch rolls 18, the pinch roll 18 is descended to drive the exclusive use body 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for controlling pinch rolls at the start of casting in a continuous casting machine that continuously casts slabs having a circular cross section.

[Prior art] In continuous casting, the dummy bar head, which is the tip of a dummy bar made by linking together multiple dummy bar bodies, is inserted into the lower part of a cylindrical mold, and molten steel is injected into the mold to form a solidified shell. Thereafter, by pulling out the dummy bar using a plurality of pairs of pinch rolls, the slab connected to the tip of the dummy bar is pulled out from the mold.

When the slab reaches the position of the pinch rolls, the pinch rolls engage with the slab and directly pull out and drive the slab, and the dummy bar is separated from the slab.

By the way, in the case of a continuous casting machine for round slabs having a circular cross section, the dummy bar body also has a circular cross section and the pinch roll has a caliber shape. FIG. 4 is a sectional view parallel to the axial direction of the pair of pinch rolls 2.3. The dummy bar dedicated body 1 has a notch extending vertically at its end, into which the plate-shaped protruding portion 5 of the dedicated body adjacent to the dummy bar is inserted, and by a horizontally extending shaft 6, both are connected to each other along this axis. They are rotatably connected around 6.

[Problems to be Solved by the Invention] However, when the dummy bar passes through the pinch rolls 2.3, the pinch rolls 2 and 3 mesh with the link connecting portions Wr and W2 of the dummy bar, and apply a large pressing force to the connecting portions. Press. For this reason, when the link joint part of the dummy bar passes through the pinch rolls, force is applied to the link joint part unevenly, causing the dummy bar head to jump up.
The dummy bar head and slab may be accidentally separated. In particular, the upper and lower ends of the dummy bar body that come into contact with the pinch rolls are likely to wear out as the dummy bar is used, making it even more likely that the protruding portion 5 will come into contact with the pinch rolls 2.3.

In order to prevent such accidents, it is possible to install a stopper or guide near the pinch roll to prevent it from jumping up, but if the cross section of the slab changes significantly, such a stopper will not work. It is not possible to sufficiently prevent the dummy bar head from jumping up.

This invention was made in view of such circumstances, and
A pinch roll control method for a continuous casting machine for round slabs that prevents the dummy bar head from jumping up and prevents the slab and dummy bar head from being inadvertently separated when the continuous casting machine for round slabs starts casting. The purpose is to provide

[Means for Solving the Problems] A pinch roll control method for a continuous casting machine for round slabs according to the present invention includes inserting a dummy bar having a plurality of interlinked dummy bar bodies into a mold, and pouring the molten metal into the mold. In a pinch roll control method for a continuous casting machine for round slabs, in which the dummy bar is pulled out and continuously cast using a plurality of pairs of pinch rollers after being injected into a mold, the pinch roller is activated when a predetermined dummy bar body passes through the pinch rolls. The roll is separated from the dummy bar exclusive body, and when a subsequent predetermined dummy bar exclusive body reaches this pinch roll, the pinch roll is brought into contact with the dummy bar exclusive body to pull out and drive the dummy bar.

[Operation] In the present invention, the pinch roll is separated from the dummy bar body between the predetermined dummy bar body and the dummy bar body following the dummy bar body. The dummy bar is pulled out and driven by other pinch rolls that are in contact with other parts. As a result, the number of link connecting portions that the pinch rolls come into contact with is reduced, and therefore, the bounce of the damino head due to uneven pressing of the pinch rolls against the link connecting portions is suppressed.

[Embodiments] Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. Fig. 1 is a sectional view showing the vicinity of the pinch rolls of a round continuous casting machine having four pairs of pinch rolls, Fig. 2 is a schematic diagram showing the dummy bar, and No. 31M (a), (t).
) is a schematic diagram explaining the operation of the pinch roll.

The dummy bar 15 and the slab 16 connected to the head 21 of the dummy bar 15 are guided by guide rolls 17 of a round continuous casting machine and conveyed in the direction of the arrow. Four pairs of pinch roll stands 11 are provided on the conveyance path of the dummy bar 15 and the slab 16.
．． 12, 13, and 14 are arranged, and the pinch rolls 18 of each stand are transferred to the dummy bar 15 or the slab 16. The rotational driving force of the pinch rolls 18 transports and drives the dummy bar 15 and the slab 16 in the direction of the arrow. The slab 16 and the dummy bar 15 have circular cross sections, similar to those shown in FIG. 4, and the pinch rolls 18
The transfer surface also has a caliber shape as in FIG. In addition, the anti-reference side of each pinch roll stand 11, etc.
The pinch roll on the upper side is driven up and down by the lifting device 10, and when the pinch roll on the opposite reference side is lowered by this lifting device 10, it presses the dummy bar 15 or the slab 16 and is transferred thereto, and when it rises, it presses the dummy bar 15 or the slab 16. distance from

As shown in FIG. 2, the dummy bar 15 includes a main body 19 and, for example, six dummy bar bodies 20. The dummy bar bodies 20 are interconnected by links 22, 23, 24, 25, 26. This link 22 etc. is the third
Similar to what is shown in the figure, the dummy bar bodies 20 are connected to each other so as to be rotatable about the horizontal axis. A dummy bar head 21 is attached to the tip of the most advanced dummy bar body 20, and the dummy bar head 21 is inserted into the mold from its lower part to start pouring molten steel.

In the pinch roll control method according to this embodiment,
First, the head 21 of the dummy bar 15 is inserted into a mold (not shown), and molten steel is injected into the mold from a tundish (not shown) to start casting.

When a solidified shell is formed in the mold, the pinch roll stands 11, 12, 13, 14 pull out and drive the dummy bar 15 via the main body 19 of the dummy bar 15. Then, the slab 16 connected to the dummy bar head 21 is pulled out from the mold, and drawing of the slab is started. and,
As shown in FIG. 3 (a), the dedicated body 20 of the dummy pad 15
When the pinch roll 18 reaches the first pinch roll stand 11, the pinch roll 18 is transferred to the dedicated body 20 and drives it. Next, when the fourth link 25 passes the pinch roll 18, the pinch roll 18 moves to the lifting device 10 (FIG. 1).
is driven upward and separated from the dedicated body 20. Then, as shown in FIG. 3(b), the second link 23 of the dummy bar 15 passes through the pinch roll arrangement position, and the special body 20
When the pinch roll 18 reaches the center of the dummy bar, the pinch roll 18 is driven downward by the lifting device 10, and transferred to the dummy bar exclusive circumferential body 20 to drive it. Other roll stands 12.13.1
The fourth pinch roll 18 also operates in the same way as the pinch roll 18 of the first roll stand 11, and from the fourth dummy bar dedicated body 2o to the middle of the second dedicated body 20, the pinch roll 1
8 is not transferred to the dedicated body 20.

Thus, in the embodiment of the invention, each pinch roll 1 of the four pairs of roll stands 11.12.13.14
8 is a dummy bar dedicated body 2 from the fourth link 25 to the central position between the second link 23 and the first link 22.
It is far from 0.

Therefore, the fourth, third and second links 25.24°23
is not pressed by the pinch rolls 18.

Therefore, the dummy bar head 21 is prevented from jumping up. Note that even when the pinch roll of a specific roll stand is separated from the dummy bar dedicated body, the pinch rolls of other roll stands are transferred to and drive the dummy bar 15 or slab 16, so the dummy bar 15 and slab 1
6 is pulled out and driven smoothly.

Note that this invention is not limited to the above embodiments, and various modifications are possible. In particular, the number of pinch roll stands is not limited to four, and the present invention can be applied to continuous casting Akebono having two or more stands. Further, the number of links of the dummy bar dedicated body is not limited to five as in the above embodiment.

[Effects of the Invention] According to the present invention, when starting continuous casting of round slabs, the pinch rolls are moved from the dummy bar to at least some of the dummy bar dedicated bodies so that the pinch rolls are not transferred to the dedicated bodies. Because they are spaced apart, at least some of the links are not pressed by the pinch rolls. Therefore, the head at the tip of the dummy bar is prevented from jumping up.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the vicinity of the pinch roll of a round continuous casting machine, FIG. 2 is a schematic diagram showing a dummy bar, and FIGS. 3(a) and (b) are schematic diagrams explaining the operation of an embodiment of the present invention. 4 are sectional views showing the pinch roll and dummy bar. 10: Lifting device, 11.12.13, 14: Stand,
15; Daminiba, 16; Slab, 18; Pinch roll, 2
0; Dummy bar dedicated body, 22.23°24.25.26;
Link

Claims (1)

[Claims] Pinch of a continuous casting machine for round slabs in which a dummy bar having a plurality of interlinked dummy bar bodies is inserted into a mold, molten metal is injected into the mold, and then the dummy bar is pulled out by multiple pairs of pinch rolls for continuous casting. In the roll control method, when a predetermined dummy bar body passes the pinch roll, the pinch roll is separated from the dummy bar body, and when a subsequent predetermined dummy bar body reaches this pinch roll, the pinch roll is separated from the dummy bar body. A pinch roll control method for a round continuous casting machine, characterized by pulling out and driving a dummy bar by bringing it into contact with a body.