JPS63215351A - Continuous casting apparatus - Google Patents

Abstract

PURPOSE:To prevent the development of seam flaw in a rolled plate and to improve the yield by arranging supporting roll just below a mold and pressing the corner part of a cast slab. CONSTITUTION:A first supporting roll 7 for holding the cast slab 5 are arranged below the mold 3 and also plural pairs of pinch rolls 8 are arranged at the downstream side. Then, a second supporting rolls 10 for pressing the corner parts of the cast slab 5 are arranged to the first supporting rolls 7. At the time of pouring the molten steel into the mold 3 through a tundish 1 and a nozzle 2, the solidified shell 4 is formed in the molten steel to become the cast slab 5, and it is guided by a dummy bar 6 and drawn. The cast slab 5 is held by the supporting rolls 7 and as the corner parts are pressed by the supporting rolls 10, the corner parts become chamfered state. Therefore, the development of seam flaw in the rolled plate, obtnd by rolling the cast slab 5 is prevented and the yield is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a continuous casting apparatus that prevents slab defects in subsequent rolling steps.

[Prior Art] For example, in the production of thick steel plates, conventionally, in the continuous casting process, molten steel stored in a ladle is poured into a rectangular cylindrical mold through a tundish, and the molten steel is poured into the mold by the mold. The cooled and produced slab is guided by a dummy bar inserted from the bottom of the mold and pulled downward by pinch rolls to continuously obtain a plate material for rolling. Next, the plate material for rolling produced in this way is heated by a rolling line directly connected to the continuous casting equipment, or after being heated in a heating furnace, is hot-rolled at a predetermined tentering ratio by a separately provided rolling line. Rolled,
We manufacture thick steel plates with predetermined shapes.

[Problems to be Solved by the Invention] However, when manufacturing a thick steel plate through the above process, seams are formed along the longitudinal direction of the steel plate at positions 20 to 3Q+u+ from the side surfaces of the front and back surfaces of the steel plate. An eave called an eave occurs.

When such eaves occur, the portion where the eaves are generated must be removed, and especially when the eaves are deep, the yield of steel sheets is significantly reduced.

This invention has been made in view of the above circumstances, and an object of the present invention is to provide a continuous casting apparatus that can produce rolled plates at a high yield without substantially generating so-called seam eaves in the rolling process. purpose.

[Means for Solving the Problems] A continuous casting apparatus according to the present invention includes a mold into which molten metal is poured from a molten metal container, and a pulling means for pulling out a slab produced by cooling the molten metal with the mold. A continuous casting device for manufacturing plate material for rolling by continuously casting slabs,
The present invention is characterized in that support rolls are provided directly below the mold to press the corners of the slab.

[Function] The inventors of the present invention have discovered that the so-called seam eaves that occur in a rolled plate are caused by the shape of the slab before rolling.

In other words, seam eaves occur when the cross section of a slab manufactured by continuous casting is rectangular or the corners of the cross section are acute, and when the corners are chamfered, seam eaves occur. do not. This invention was made based on this knowledge, and by providing a support roll that presses the corner of the slab directly under the mold of the continuous casting machine, the continuously cast slab can be pressed against the corner of the slab. is in a chamfered state, thereby solving the above problem.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing a continuous casting apparatus according to this embodiment. The tundish 1 is composed of an iron shell lined with a refractory material, and molten steel is injected from a not-shown steel plate. A submerged nozzle 2 is attached to the bottom of the tundish 1, and molten steel is injected into a mold 3 provided below the tundish 1 through the nozzle 2. The mold 3 is made of copper and has a cylindrical shape. This mold 3 is water-cooled with cooling water, and is designed to cool the molten steel injected from the tundish 1 to produce slabs 5. This slab 5 has a solidified shell 4, and at the start of casting, the slab 5 is guided downward by a dummy bar 6. A plurality of pairs of first support rolls 7 are disposed below the mold 3, and the first support rolls 7 hold the slab 5 so that the slab 5 can absorb the molten steel in its unsolidified portion. It is designed to prevent deformation due to static pressure. Adjacent to the first support roll 7 directly below the mold 3, a second support roll 10 for pressing the corner of the slab 5 pulled out from the mold 3 is arranged as shown in FIG. It is set up. 1st
A nozzle 9 is disposed between the support rolls 7, and cooling water is sprayed from the nozzle 9 onto the slab 5 to promote solidification of the slab. A plurality of pairs of pinch rolls 8 are disposed downstream of the first support roll 7, and the pinch rolls 8 are rotationally driven by a drive device (not shown) to pull out the slab 5. .

In the continuous casting apparatus configured in this way, first,
Molten steel is injected into a mold 3 from a ladle through a tundish 1 and a nozzle 2. Then, this molten steel is cooled by the mold and becomes a slab 5 in which a solidified shell 4 is formed. This slab 5 is guided by a dummy bar 6 and pulled out by a pinch roll 8. In this case, the slab 5 is held by the first support roll 7 and is further held by the second support roll 10.
The corner is pressed. Then, since the inside of the slab 5 is not solidified, the pressed portion is easily deformed and the corner thereof becomes a chamfered shape. While the slab 5 is being pulled out, cooling water is sprayed from the nozzle 9 to promote solidification, and by the time it reaches the pinch rolls 8, the inside of the slab 5 is almost completely solidified. pinch roll 8
After passing through, the slab 5 is rolled by a hot rolling line at a tentering ratio of 3.0, for example, into a thick steel plate.

Since the thick steel plate manufactured in this manner has chamfered corners, substantially no seam eaves occur. In this case, the amount of pressure applied to the corners of the slab 5 varies depending on the slab shape and the tenting ratio, but for example, when the tenting ratio is 3.0, the plate thickness is
When manufacturing a thick steel plate of 1I11, it is sufficient to have a zero surface of 40a+s+ or more.

In addition, in this embodiment, although the case of a thick steel plate is shown, the present invention is not limited to this, and can be applied to any plate material in which seam eaves occur.

In this example, since the slab after passing through the continuous casting apparatus is in a chamfered state, there is no need to further chamfer the slab, and the yield can be maintained extremely high.

[Effects of the Invention] According to the present invention, the support rolls that press the corners of the slab are disposed directly below the mold, so that the continuously cast slab has a chamfered shape. Therefore, seam eaves are not substantially generated in the rolled plate during the rolling process. Therefore, rolled plates can be manufactured with a high yield. Further, since the chamfered portion is formed on the slab when it leaves the mold of the continuous casting apparatus, there is no need to chamfer the slab, and a rolled plate can be obtained with extremely high efficiency and high yield.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a continuous casting apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing a support roll. 1: tanditshu, 3: # type, 5: slab, 7: first support roll, 8: vinyl roll, 10: second support roll Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Claims] Continuous casting has a mold into which molten metal is poured from a molten metal container, and a pulling means for pulling out the slab produced by cooling the molten metal using the mold, and continuously casts slabs to produce plate material for rolling. A continuous casting apparatus, characterized in that a support roll for pressing a corner of the slab is provided directly below the mold.