JPS59107751A - Method and device for continuous casting of hoop iron - Google Patents

Abstract

PURPOSE:To form a fine internal texture and to make the plate thickness uniform and to increase the casting speed of a steel plate by pressurizing a molten steel in a half molten state and conducting the same to the outside circumferential part of two cooling rolls which are disposed in parallel. CONSTITUTION:The molten steel 10 in a tundish 7 is pressurized by a pressurizing feed pump 6, by which the molten steel 10 is fed into a guide flow passage 5. The internal pressure of the molten steel 10 in the passage 5 is made uniform by the pressurizing operation and the steel 10 made into a slurry 11 in a half molten state is fed by the pressure, by which the steel is stirred and dendrite is broken. The uniform solid-liquid mixed slurry is thus obtd. The slurry 11 contacts with cooling rolls 1, 1, and as the rolls 1, 1 rotate, the slurry move to the gap thereof while growing solidified layers 12, 12. The layers 12, 12 grown on the peripheral surface of both rolls 1, 1 come into close contact with each other in the stage of passing the gap and is delivered as a steel plate 2 from the gap.

Description

[Detailed Description of the Invention] The invention is to directly cast a steel plate from molten steel, and the molten steel in a semi-molten state is pressurized and guided to the outer periphery of two cooling rolls arranged in parallel. The present invention relates to a continuous strip casting method and apparatus for continuously casting copper strips while cooling and solidifying molten steel.

The most common method for manufacturing steel sheets, which is still practiced today, is to roll a thick slab made by continuous slab casting 5 to 10 times or more to produce a thin sheet. However, this method consumes a large amount of rolling energy and heating energy for maintaining the temperature of the steel material during the rolling operation.

In order to reduce such rolling energy and heating energy, a method of directly casting a steel plate from molten steel has recently been proposed.

That is, methods for directly casting steel sheets can be broadly classified into the twin roll method and the belt method.

The belt method attempts to create a board on a belt,
There are problems in that it is difficult to obtain belt materials that can withstand high-temperature molten steel, and that it is difficult to make a flat plate due to thermal distortion of the belt.

The twin roll method includes two types of stitching, such as the top stitching method as shown in Figure 1, the bottom stitching method as shown in FIG. 2, the horizontal stitching method as shown in FIG. 6, and the remainder stitching method as shown in FIG. Roll of books (
α) are placed in parallel and the molten steel (c) is placed between both rolls (a).
A channel wall (b) is provided through which a steel sheet (d) is cast through the gap between both rolls (α). Both of these methods are considered to be relatively easy to manufacture, but the contact length between the molten steel and the rolls is short and the cooling time is long, so the casting speed cannot be increased, and non-metals tend to segregate in the center of the steel sheet. There are disadvantages such as cavities are easily formed due to shrinkage during solidification, and the molten steel is easily contaminated because the molten metal surface is exposed to the atmosphere.

The present invention has been developed in view of the above-mentioned circumstances.The present invention has been developed to produce a continuous strip in which a pair of rotating cooling rolls are held in a required gap and arranged in parallel, and a steel plate is cast from the gap. In casting, the molten metal is made to flow at least along the circumferential surface of the cooling roll under knife edge pressure, and the molten steel in this flowing state is made into a semi-molten state, and the flow is agitated to eliminate the uneven distribution of non-metals and to improve the flow of the molten metal. This allows for rapid solidification, miniaturization of the internal structure, uniform plate thickness, and improved surface properties.

Embodiments of the present invention will be described below with reference to the drawings.

In Figures 6 and 7, cooling rolls (1), (1) whose inner surfaces can be cooled with water, etc. are maintained at a gap corresponding to the thickness of the steel plate (2) to be cast. The cooling rolls (1) are arranged so as to be rotatable in parallel to each other, and are arranged around the outer peripheries of the cooling rolls (1) in a substantially concentric shape except for a part, and converge near the gap. ) to form. A fan-shaped induction flow path (5) whose width becomes wider than the hot water supply port (4) is connected to the concentric circular flow path (3), and the hot water supply port (4) is connected to the water supply port (4) through a pressurized injection pump (6). 7) is connected. A cooling device (not shown) is disposed around the periphery l2II of the guiding flow path (5) (the guiding flow path (5) may be made into a double pipe to allow cooling water to flow in parallel). The plate temperature fg is such that the molten steel flowing inside becomes a semi-molten slurry.

Both cooling l-ru (1), exit side of steel plate (2) of (1) (
Both cooling rolls (1), (anti-center circular flow path with 11 gaps)
A foot guide (8) that promotes peeling of the steel plate (2) from the cooling roll (1) and further guides the steel plate (2) downward.
A guide roll (
9).

The molten steel @O0 of Tandy 2 Tsushu (7) is pressurized and injected with molten steel 00) into the guiding channel [5] by the pressurized injection pump (6).

The molten steel 00) in the guide channel (5) gradually becomes a wider flow along the shape of the guide channel (5), and the pressurized injection pump (
The internal pressure is equalized by the pressurizing operation 6). Furthermore, the molten steel 00, which has become a semi-molten slurry αη in the induction channel (5), is agitated because it is fed under pressure, destroying dendrites (a state in which non-metals are unevenly distributed), and creating a uniform solid-liquid mixture. Make it slurry. The slurry'J (11) eventually comes into contact with the cooling roll (1) and moves to the gap while growing a solidified layer due to the rotation of the cooling roll (1). Sura IJ
Slurry is replenished by pressure into the contracted portion of (11) during solidification to prevent the formation of cavities, and the steel plate (2) has a uniform thickness and good surface quality. Furthermore, by applying pressure to the slurry α, the heat transfer efficiency between the slurry (1) and the cooling roll (1) is further improved, the slurry (1υ) is rapidly solidified, and its structure is refined.

Thus, the solidified layer side grown on the circumferential surface of both cooling rolls (LL (1), @, comes into close contact with each other when passing through the gap, and is sent out from the gap as a steel plate (2).

In the above embodiment, the steel plate is pulled out downwardly, but it goes without saying that it can be pulled out horizontally or upwardly, and it goes without saying that various pressurizing means can be used, such as not only a pressurizing pump but also filling compressed gas. As described above, according to the present invention, (1) Since the steel plate is cast from semi-molten molten steel, the welding speed of the steel plate can be increased. (11) Therefore, matching with a rolling mill is possible, and the casting process and rolling process can be made faster. (b) It is possible to produce steel plates with uniform plate thickness and surface texture; (1v) Since the flow path is closed, it is possible to greatly simplify the equipment. It exhibits excellent effects such as no contamination of molten steel, and (■) the ability to manufacture steel plates with excellent internal quality.

[Brief explanation of drawings]

Figures 1 to 5 are explanatory diagrams of a conventionally considered twin-roll continuous casting system, Figure 6 is a schematic diagram of an apparatus according to the present invention, and Figure 7 is a view taken along arrow A-A in Figure 6. It is a diagram. (1) is a cooling roll, (2) is a steel plate, (3) is a concentric channel, (5) is a guiding channel, (6) is a pressurized injection pump,
Q indicates molten steel. Patent applicant Ishikawajima Harima Heavy Industries Co., Ltd. 7' Figure 3 Figure 4F Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1) In a continuous strip casting method in which a pair of rotating cooling rolls are held in parallel with a required gap and a steel plate is cast from the gap, at least cooling is performed. A method for continuous casting of strips, characterized in that the molten metal is allowed to flow under pressure along the circumferential surface of a roll, and the molten metal in the flowing state is in a semi-molten state. 2) A pair of rotating cooling rolls are maintained in parallel with a required gap, and a closed concentric flow path is formed along the circumferential surface of the cooling rolls, and the circular flow path gradually becomes wider. The guide channel is connected to the guide channel, and the molten metal is injected under pressure into the guide channel, and the molten metal in both channels is cooled so that the molten metal becomes a semi-molten state at least in the circular channel. Features: Continuous strip casting equipment.