JPH04327353A - Method for supplying powder in continuous casting and powder for continuous casting - Google Patents

Abstract

PURPOSE:To enable uniform supply of powder onto molten metal surface, to eliminate fear of development of dust and to provide the powder having contribution to improvement of working environment by supplying the powder for continuous casting as sheet-state. CONSTITUTION:The powder for adding on the surface 4 of molten steel 3 in a mold 2 for continuous casting, is formed as the sheet-state providing plane shape corresponding to the plane shape of the molten steel surface 4 in the mold. At the time of putting the powder sheet 21 on the molten steel surface 4, the holding material of binder, etc., for holding the powder as the sheet-state is dissolved with the molten steel 3 and holding of the powder is released. By this method, the powder returns back to the ordinary powdery and granular bodies, and effectively acts as adding agent to the molten steel 3.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for supplying powder in continuous casting and powder for continuous casting.

0002

BACKGROUND OF THE INVENTION In continuous casting, powder is added to molten steel in a mold. This powder is C
It is usually a mixture of two or more types of single substances or compounds such as aCO3, SiO2, NA, C, Li, etc.,
There are two types of shapes: granules, which are formed into small particles and dried, and powder products, which are mixtures of finely powdered raw materials. Regardless of the type of powder, it is essential that it be uniformly spread over the surface of the molten steel in the mold.
It is spread using mechanical feeding devices such as spring feeders and screw conveyors. In order to improve the uniformity of this distribution, the distribution ports of the spring feeder and screw conveyor are moved above the melt surface, and many improvements have been made to the feeding device itself as well as its movement and control mechanisms. Proposed.

0003

[Problems to be Solved by the Invention] However, no matter how much the spraying port is moved, the powder is still sprayed linearly, and there is a limit to improving the uniformity of the spraying. In addition, nozzles are suspended above the hot water surface, and it is necessary to move the spring feeder or screw conveyor to avoid these nozzles, making it even more difficult to improve the uniformity of powder distribution. Furthermore, as long as powder is being dispersed, it is impossible to avoid the generation of dust, and it is desired to improve the working environment due to this dust generation.

0004

[Means for Solving the Problems] Accordingly, the first invention is a method for supplying powder to be added to the surface of molten steel in a mold in continuous casting, the powder being added to the surface of molten steel in a mold. The powder sheet is arranged in a sheet-shaped body with a planar shape corresponding to the planar shape, and by placing this powder sheet on the surface of the molten steel in the mold, the powder is evenly supplied onto the surface of the molten steel. The above problem is solved by providing a method for supplying powder.

[0005] Furthermore, the second invention solves the above problem by providing a continuous casting powder having the following configuration. This powder is arranged in a sheet-shaped body having a planar shape corresponding to the planar shape of the molten steel surface in the mold. This powder sheet is composed of fine powder and a holder that holds these powders and forms the entire sheet. This holder is constructed of a material that releases support for each powder by melting upon contact with the molten steel in the mold. Furthermore, in a third invention, the thickness of at least the peripheral edge of the powder sheet of the second invention is made larger than the thickness of the central part, and the powder sheet is placed on the surface of the molten steel in the mold. The present invention is characterized in that the peripheral edge portion is positioned above the molten metal surface near the wall surface of the mold.

[0006]

[Operation] The holder of the powder sheet placed on the surface of the molten steel in the mold is melted by the high heat of the molten steel, and the bond of the powder is broken. As a result, the powder returns to its normal granular state and effectively acts as an additive to molten steel.

[0007]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. FIG. 1 is a perspective view of a powder sheet of one embodiment,
FIG. 2A is an explanatory view of the powder sheet placed on the surface of molten steel in the mold, seen from the side, and FIG. 2B is an explanatory view of the same state, seen from above.

This powder sheet 1 is formed into a sheet by bonding powder with a binder serving as a holder, and has a planar shape corresponding to the planar shape of the molten steel 3 surface 4 in the continuous casting mold 2. have In this embodiment, it has a rectangular planar shape corresponding to the mold 2 which is rectangular in plan view. In this embodiment, the entire hot water surface 4 is covered with one sheet, but the entire hot water surface 4 may be covered with two or more sheets. Also, the size of the powder sheet 1 is approximately the same as the planar area of the hot water surface 4, but as shown in the figure,
It may be formed to be a little smaller than the flat area of the hot water surface 4, or conversely, it may be formed a little larger, and when covering the hot water surface 4 with this sheet, the excess portion is made to follow the inner wall surface of the mold 2. It's okay. Note that 5 in the figure indicates a nozzle.

[0009] This powder sheet is composed of a large amount of fine powder and a binder that binds these powders together. This fine powder is the same as before.
It is a mixture of two or more single substances or compounds, and its shape can be either a so-called granule product formed into small particles and dried, or a powder product that is a mixture of finely powdered raw materials. good. On the other hand, the binder is preferably one that dissolves upon contact with the molten steel 3 in the mold, such as a starch such as corn starch or a synthetic resin.

[0010] This powder is formed into a sheet-like body by a conventional method for joining powder and granular materials with a binder.
It is preferable not to apply strong pressure during this bonding so that the powder quickly returns to its original granule or powder form when the binder is dissolved. Also, inside the powder sheet 1,
It is desirable that the granules or powdered products are uniformly distributed, and that the thickness of the sheet is also uniform.

However, it is preferable that the thickness of the peripheral portion 6 of the powder sheet 1 be larger than the thickness of the central portion 7 in order to obtain substantial uniformity in the supply amount. That is,
Normally, the amount of powder consumed at the surface near the inner wall of the mold 2 is higher than that at the center, and correspondingly,
It is advantageous to increase the wall thickness of the peripheral edge 6 so that the amount of powder is greater than in other parts. Further, as shown in the figure, when the area of the powder sheet is formed to be slightly smaller than the planar area of the molten metal surface 4, the molten metal surface near the inner wall surface of the mold 2 is
Since it is not covered by the powder sheet 1, it is desirable to make the thickness of the peripheral edge part 6 larger than other parts in order to ensure the supply of powder to that part. More specifically, the thickness of the peripheral portion 6 is 25 to 30
15 to 20 mm is appropriate for the wall thickness of the central part 7, but these values vary depending on the amount of powder required in one supply, the content of powder in the powder sheet, etc. What is necessary is just to change it suitably and implement it. In addition, if it is possible to specify a portion other than the peripheral portion 6 where the amount of powder consumed is large, it is also possible to make the wall thickness of the portion larger than that of the other portions.

Next, an example of a method for supplying powder to the surface 4 of molten steel 3 in the mold 2 for continuous casting using the powder sheet 1 will be explained with reference to FIGS. 3 and 4. FIG. 3 is an explanatory side view of the step of placing a powder sheet on the surface of molten steel in a mold according to one embodiment, and FIG. 4 is an explanatory view of the same step viewed from above.

The powder sheet 1 may be manually placed on the surface 4 of the molten steel 3 in the mold 2 by an operator, but in this embodiment, in order to increase the safety of the work, A method of mechanically feeding the sheet from a position away from the mold 2 is shown. First, to explain the configuration of this supply device, this device includes a pair of left and right arms 11 arranged in parallel, and a support portion 12 provided at the tip of each arm 11.
and has. Both arms 11 are configured to move in parallel at the same time using appropriate means such as hydraulic cylinders, but may be moved using other means. The support part 12 has a clamping body 13 at its lower part, and this clamping body 13 clamps both left and right ends of the powder sheet 1 by rotating around a hinge 14 by an appropriate drive source such as an electric motor.・It is configured to be open.

When supplying the powder sheet 1, first, both arms 11 are moved back to a position away from the mold 2, and
Both ends of the powder sheet 1 are held between the holding bodies 13 of the support part 12. Then, both arms 11 are moved forward, and the powder sheet 1 supported by the support part 12 is inserted between the mold 2 and the nozzle 5. Next, when the powder sheet 1 is released by rotating the left and right holding bodies 13, the powder sheet 1 naturally falls onto the molten metal surface 4 of the molten steel 3 in the mold 2, and is placed on the molten metal surface 4. It will be done. Hot water level 4
The binder of the powder sheet 1 placed thereon is melted by the high heat of the molten steel 3, and the powder bonds are broken. As a result, the powder returns to its normal granular state and effectively acts as an additive to the molten steel 3.

In order to release the powder sheet 1 from closer to the surface 4 of the molten steel 3 in the mold 2, appropriate means such as an arm that extends and retracts up and down is provided on the lower surface of the support. The powder sheet may be supported at the tip. Further, instead of the holding body, the powder sheet may be supported by other means such as a suction cup equipped with a suction mechanism. Further, in addition to this embodiment, the powder sheet may be supplied by other conveying means such as a conveyor.

Next, another embodiment will be explained based on FIG. These powder sheets 21, 21 are suitable for continuous casting equipment equipped with a submerged nozzle 22 whose nozzle tip is suspended below the molten steel level 4, and a set of two powder sheets 21, 21 is suitable for a continuous casting facility equipped with a submerged nozzle 22 whose nozzle tip is suspended below the molten steel level 4.
This covers the entire area of the molten steel surface 4 within the molten steel 3. Each powder sheet 21 has a rectangular shape corresponding to half of the hot water surface 4, and has a substantially semicircular recess formed therein corresponding to the shape of the immersion nozzle 22. The recessed peripheral edge 23 and the peripheral edge 24 of the outer edge of the sheet are formed thicker than the central part 25. Of course, even in this embodiment, the peripheral portions 23 and 24 may be made to have the same thickness as the central portion 25, or only the concave peripheral portion 23 may be made thick, or other modifications may be made as appropriate. Further, it is also possible to perform processing to the extent that only one cut line is provided without providing a substantially semicircular recess. Furthermore, as shown in FIG. 5(C), each powder sheet 21
, 21 may be formed, or the powder sheet may be further divided into a large number of pieces.

These powder sheets 21, 21 are transferred from both sides of the mold 2 (top and bottom in FIG. 5B) to the center and placed there. As this transfer device, devices similar to those in the previous embodiment may be provided on both sides. Note that the powder sheets 21, 21 may be placed with a slight interval between them, or may be placed so as to overlap each other. In this case, it is also preferable that the thickness of the overlapping portion be smaller than the thickness of the other portions.

The present invention is not limited to the above-mentioned embodiments, but can be carried out with appropriate modifications. For example, in a method of forming powder into a sheet, the holding body may be made of synthetic resin or non-woven fabric with two front and back sides. It may be made into a sheet by using two thin sheets and sandwiching powder between the thin sheets. In this case, in order to prevent the powder from being unevenly distributed during transportation, it is also desirable to divide the front and back sheets into a grid pattern. Alternatively, a powder sheet may be obtained by applying a binder to the surface of a sheet made of non-woven fabric or synthetic resin to make it sticky, and then uniformly scattering powder on the surface. In these cases,
The powder may be placed on the sheet immediately before being supplied to the hot water surface, but from the viewpoint of preventing deterioration of the working environment, it is preferable to do so in a demarcated area with dust-proof equipment. This powder sheet may be formed in advance to correspond to the planar shape of the hot water surface as in the embodiment, but it may also be carried to the site in the form of a long roll. In this case, the width of the roll is made to correspond to the width of the hot water surface, and the powder sheet fed out from the roll is cut to correspond to the length of the hot water surface before being transferred, and the cut powder sheet is placed on the hot water surface. You can take the method of placing If it is expected that multiple types of molds will be used, the width of the roll should be adjusted to correspond to the largest mold, and if a smaller mold is used, the width and length of the roll should be adjusted to correspond to the width and length of the molten metal surface before transfer. It may also be cut. In addition to supplying the powder using the powder sheet, it is also possible to use conventional mechanical powder dispersion.

[0019]

As described above, in the first invention, by fundamentally changing the powder supply method, powder is supplied as one surface, uniform powder supply is realized, and dust generation is reduced. It has been possible to provide a method for supplying powder that eliminates all risks and contributes to improving the working environment. In the second invention, there is provided a powder for continuous casting which can realize a uniform supply of powder by making the powder into one surface, and can also contribute to improving the working environment by eliminating the risk of dust generation. It could have been done. In the third invention, the second invention is further improved to provide a powder for continuous casting that is compatible with powder consumption in molten steel and can supply powder substantially more uniformly. .

[Brief explanation of drawings]

FIG. 1 is a perspective view of a powder sheet of one embodiment.

FIG. 2(A) is an explanatory view of a state in which a powder sheet is placed on the surface of molten steel in a mold, viewed from the side. (B) is an explanatory diagram of the same state viewed from above.

FIG. 3 is an explanatory diagram, seen from the side, of the step of placing a powder sheet on the surface of molten steel in a mold according to one embodiment.

FIG. 4 is an explanatory diagram of the same process seen from above.

FIG. 5(A) is an explanatory view of a state in which a powder sheet according to another embodiment is placed on the surface of molten steel in a mold, viewed from the side. (B) is an explanatory diagram of the same state viewed from above. (C) is a plan view showing an example of a change in the planar shape of the powder sheet.

[Explanation of symbols]

1, 21... Powder sheet, 2... Mold, 3... Molten steel, 4...
Hot water surface, 5, 22... Nozzle, 6, 23, 24... Periphery, 7
, 25... Central part, 11... Arm, 12... Support part.

Claims (3)

[Claims] Claim 1: A method for supplying powder to be added to the surface of molten steel in a mold in continuous casting, wherein the powder is disposed in a sheet-shaped body having a planar shape corresponding to the planar shape of the surface of molten steel in the mold. Powder supply in continuous casting, characterized in that the powder sheet is placed on the surface of the molten steel in the mold to uniformly supply the powder onto the surface of the molten steel. Method. [Claim 2] Powder added to the surface of molten steel in a mold in continuous casting, the powder being arranged in a sheet-like body having a planar shape corresponding to the planar shape of the surface of molten steel in the mold. This powder sheet is composed of fine powder and a holder that holds these powders and forms the entire sheet, and this holder melts when it comes into contact with molten steel in the mold. , a powder for continuous casting, characterized in that it releases the support of each powder. 3. The thickness of at least the peripheral edge of the powder sheet is larger than the thickness of the central part, and when this powder sheet is placed on the surface of molten steel in the mold, the peripheral edge 3. The powder for continuous casting according to claim 2, wherein the powder is located above the molten metal surface near the wall surface of the mold.