JPS58187244A - Formation of shell in continuous casting installation for ingot - Google Patents

Abstract

PURPOSE:To form a shell having uniform wall thickness continuously and to produce an ingot having a good internal characteristic by retarding the cooling in the part of molten metal in contact with both end parts of twin mold rolls than the cooling in the part in contact with the central part thereof. CONSTITUTION:The central part 1B on the outside circumferential surface of twin mold rolls 1 of a continuous casting installation for an ingot is constituted of pure copper or silver copper having excellent heat conductivity and both end parts 1A, 1C on the outside circumferential surface thereof are constituted of a copper alloy, chromium copper, chromium-zirconium copper, berrylium copper, etc, having the heat conductivity lower than the heat conductivity of pure copper. If molten metal 7 is charged into a casting mold 10 formed of such rolls 1 and gates 5, 6 to form a shell 8, the cooling at both side edges in the long side parts of the shell 8 is retarded more than the cooling in the central part, and in the end, all parts are formed to have a uniform wall thickness. The shell 8 is drawn out as an ingot 9, whereby the ingot 9 having a good internal characteristic without any crack, etc. at four corners is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shell forming method in continuous slab casting equipment in which a slab is drawn from between twin mold rollers.

An outline of a conventionally known continuous casting equipment for cast slabs using twin mold rollers will be explained with reference to FIG. (1)
are twin mold rollers approaching each other, (2) (3
) is a pinch roller and a guide roller that constitute a slab conveyance path extending downward from directly below both rollers (1), (4)
is tanditshu nozzle, (5) (e) halo (
1) A pair of long side weir and short side weir disposed on the top. The molten metal (7) is completely cooled by the cooling water supplied inside to form a shell (8),
The slab is pulled out in the direction of the arrow, but at this time the cooling rate of the molten metal (7) is determined by the four corners of the mold formed by the platen (5) (6) and the roller (1). The molten metal (7) at the four corners solidifies quickly to form a shell (8).

Therefore, when the molten metal (7) moves further in areas other than the four corners of the mold head, the shells (8) at the four corners are pulled, which tends to cause crackling υ.

Therefore, the present invention provides a shell forming method that solves these problems.The main feature of the present invention is that g-molten metal is injected between twin mold rollers that are close to each other, and the molten metal is poured into both ends of the twin mold rollers. It is possible to continuously form a shell with an even thickness in all parts by cooling the contacting part later than the part in contact with the central part. According to this method, cracks will not occur at the four corners of the slab. However, it is possible to provide slabs with good internal properties.

A first embodiment of the present invention will be described below with reference to FIGS. 3 to 5. That is, the center part (IB) of the outer peripheral surface of the twin mold roller (1) is made of pure copper or silver copper with excellent thermal conductivity, and both ends (IA) (IC
) has lower thermal conductivity than pure copper, such as copper alloys, chromium copper,
It is composed of chromium-zircon copper, beige IJ chromium copper, etc.

In addition, when the center part (IB) of the outer peripheral surface is made of low-alloy copper, it can be implemented by using heat-resistant steel at both ends (IA) (IC)', without eating up the material of the 10-L proper. It is also possible to achieve the same effect by changing the surface treatment between the center and both ends of the roller. For example, the center of the outer peripheral surface (IB) is not surface treated, while the center of the outer circumferential surface (IB) is not subjected to surface treatment, while both ends are Part (IA) (IC) is Ni
The desired purpose can be achieved by plating or N1 alloy plating, and N1 plating or N1 alloy plating can be applied to the central part (IB)
For those with i-alloy plating, both ends (IA) (
IC) can be applied with self-fusing alloy plating or ceramic coating, making it possible to implement each of them.

In the above configuration, when the molten metal (7) is poured into the mold uQ formed by R1 (5J (6)) and the twin mold roller (υ), a shell (8) is formed.
At this time, since both side edges of the long side of this shell (8) are in contact with both ends (LA) and (IC) of the roller (1) made of copper alloy, cooling of these side edges is delayed compared to the central part. In the end, a shell (8) with equal wall thickness at each part is formed.
Next, by pulling out the slab (9) in the direction of the arrow (4), the shell (8) is continuously held between the twin mold rollers (1), and has a good internal structure with no cranks at the four corners. Slab (
9) It is something that can be pulled out.

A second embodiment of the present invention will be described based on 1ft FIG. 6. In other words, both ends (IA
) (IC)'ft A first cooling channel @ for cooling and a second cooling channel (towards) for cooling its central part (IB) are provided,
The amount of cooling water in the cooling/K path (6) is made smaller than that in the second cooling channel μs.

According to the above configuration, since both ends (IA) (IC) of the twin mold roller (1) cool down more slowly than the center part (IB), each part of the shell (8) The wall thickness can be made uniform.

A third embodiment of the present invention will be described based on FIG. That is, twin mold rollers (1) (7) outside MI
The oil film thickness (δl) at both ends (14AX14C) of the lubricating oil 04 supplied to the outer peripheral surface of the roller (1) to prevent wear of the roller (1) is calculated as the oil film thickness (δ2) at the center (14B).
It's bigger than that.

According to the above configuration, both ends (14A) (
Since the heat transfer resistance of the shell (14C) is greater than that of the central portion (14B), the thickness of each portion of the shell (3) can be made equal, as in the first embodiment.

As described above, according to the shell forming method in the continuous slab casting equipment of the present invention, the portions of the molten metal in contact with both ends of the twin mold rollers are cooled more slowly than the portions in contact with the center, so that all portions are uniformly thick. Continuously forming the shell eliminates the occurrence of cranks at the four corners of the slab, which results in an engineering ship, and makes it possible to provide the entire slab with good internal properties.

[Brief explanation of drawings]

Figure vJ1 is a schematic explanatory diagram of a continuous slab casting equipment using twin mold rollers, Figure 2 is a cross-sectional plan view showing the state of shell formation, and the first cooling channel diagram shows the first embodiment of the present invention. Figure 3 is a schematic longitudinal sectional view, and Figure M4 is IV-I in Figure 3.
V arrow view, Figure 5 is v Y arrow view of Figure 3, Roruichi 6
This figure is a schematic plan view showing a second embodiment of the present invention, and FIG. 7 is a schematic plan view showing a third embodiment of the present invention. (1,)...Twin mold roller, (LA)...
End, (lB)...Center, (IC)...End, (
7)... Molten metal, (8)... Shell, (9)... Slab, 01... Crack, @... First cooling channel, @.
...Second cooling waterway, Q4...Tan oil agent Mori
Hiroshi Moto Ebisu Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 δ

Claims (1)

[Claims] 1. Twin mold loaf 1MjK molten metal is injected close to each other, and the portions of the molten metal that contact the ends of the twin mold rollers are cooled slower than the portions that contact the center, thereby continuously forming a shell with an even thickness in all parts. A shell forming method in continuous cast slab casting equipment.