JPS62292247A - Powder supplying apparatus into mold for continuous caster - Google Patents

Abstract

PURPOSE:To uniformly supply the prescribed quantity of powder on molten steel surface in a mold by providing an inner cylindrical body opening a tip of powder spraying part into the mold and forming plural spraying holes as cylindrical shape, and an outer cylindrical body forming trapezoid-like slit, which changes the opening area of each spraying hole. CONSTITUTION:The powder 6A discharged at the constant quantity is dropped into a storage tank 8 from a vertical tube 7 and further sent to a supplying part 10 by horizontal carrying 9. Next, the powder 6A is sprayed almost at the same quantity from the opening 29 of the tip arranged at the spraying part 10 and the spraying hole 31a-31c. In case of changing the spraying quantity by changing the number of revolution for a spring feeder 9, the outer cylindrical body 28 forming the trapezoid- like slits 32a-32c is rotated to change the opening area for each hole 31a-31c. Then, as angle by the faced sides of trapezoid for the slits 32a-32c is formed as large toward upstream direction, change of opening degree of the spraying hole at the upstream becomes to large and the spraying quantity from each spraying hole makes to the same quantity in the number of revolution at this time, and so supply of the powder into the mold is smoothly executed.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Industrial Application Field] The present invention relates to a powder supply device to a mold for a continuous casting machine, and more particularly, to a method for preventing oxidation of the surface of molten steel poured into a mold. , relates to a device for injecting powder for heat retention and lubrication between the mold and the billet.

[Prior art]

In continuous casting, in which molten steel is cast into a continuous billet or the like having a predetermined cross-sectional shape, the molten steel is poured into a mold from a ladle or the like through a nozzle. While passing through the mold, the molten steel gradually solidifies and is cast into a shape corresponding to the cross section of the mold, and a continuous billet is pulled out from the other end of the mold. At this time, powder is supplied to prevent oxidation of the molten steel and to lubricate the molten steel and the mold.

The tip of a nozzle that pours molten steel from a ladle into a mold is plunged into the molten steel in the mold, and is separately controlled so that the molten steel surface is always at a substantially constant height.

The dimension between the facing walls of the mold is the cross-sectional dimension of the billet, and the upper end of the mold is open except for the nozzle part that protrudes, and the molten steel surface is open to the atmosphere. Therefore, the above-mentioned powder is appropriately introduced through the opening and taken into the mold together with the molten steel which is solidified and drawn out.

Various types of powder are generally used, and the powder may be supplied into the mold by scattering it to the extent that it thinly covers the surface of the molten steel.

The powder prevents oxidation of the molten steel in the mold, keeps it warm, and captures floating inclusions, and also promotes sliding between the inner wall of the mold and the molten steel that is starting to solidify, and improves mold separation. Therefore, the cast molten steel can be solidified to a desired degree while passing through the mold, and can be drawn out smoothly.

[Problem that the invention seeks to solve]

As described above, powder is supplied to the surface of the molten steel in the mold for the purpose of preventing oxidation and lubricating the powder, but the amount thereof is approximately constant. However, it is often changed depending on, for example, the dimensions of the billet to be cast, the composition of the molten steel, the usage conditions of the mold, and other factors.

Incidentally, it is preferable that the powder be supplied to the surface of the molten steel as evenly as possible, and the amount must be adjusted appropriately, so it is not easy to mechanize it, and conventionally it has been supplied manually or by intuition. Adjustments have been made. Powder is poured onto the molten steel surface by scattering it through the opening at the top of the mold, but this work requires skilled workers to select the appropriate timing and amount of supply as well as ensure uniform distribution. It disappears. Moreover, the working environment is in a high temperature atmosphere, and workers are forced to perform harsh labor.

The present invention was made to solve the above-mentioned problems, and its purpose is to be able to supply a predetermined amount of powder to the molten steel surface in the mold in an evenly distributed manner, and to change the amount of powder supplied into the cylinder. Provides a powder supply device for a mold for a continuous casting machine that can obtain the desired oxidation prevention and lubrication, eliminate the manual labor and skill required by the operator, and relieve the operator of harsh work. It is to be.

[Means for solving problems]

The features of the apparatus for supplying powder to a mold for a continuous casting machine according to the present invention will be explained with reference to FIGS. 1 and 2. The powder 6 that has been conveyed in a fixed amount is dropped into a reservoir 8 through a vertical pipe 7, and the powder held at a predetermined layer height in the reservoir 8 is carried out by a spring feeder 9 whose rotation speed can be changed. This is a powder supply device configured to scatter powder onto the molten steel surface of a mold 1 for a continuous casting machine from a scattering section 10 provided at the tip of a feeder 9. Spray hole 3
An inner cylindrical body 27 in which 1a to 31c are formed in a cylindrical portion 30, and an outer cylindrical body 2 in which substantially trapezoidal slits 32a to 32c are formed to change the opening area of each of the dispersion holes 318 to 31c.
8, and the slits 328 to 32c are formed such that the angle α of the opposite sides of the trapezoid becomes thicker toward the upstream side, and the air supply pipe 33 is connected to the inner cylinder body 27.

[For production]

The powder 6 that has been cut into a fixed amount and transported is transferred to a storage container 8 as it falls inside a vertical pipe 7. The amount of powder is adjusted in the reservoir 8 so that the layer height is approximately constant, and from there, the powder is conveyed horizontally by a spring feeder 9 and reaches the spreading section 10. The dispersion section 10 has an opening 29 at the tip of the inner cylinder 27 and dispersion holes 318 to 31c provided therein, and approximately the same amount of powder 6 is sprayed from each of them. When increasing or decreasing the amount of spraying by changing the rotational speed of the spring feeder 9, the opening area of each spraying hole 318-31c is adjusted by rotating the outer cylindrical body 28 in which the trapezoidal sulins 32a to 32c are formed. change. At this time, since the trapezoidal side angles of the slits 32a to 32e are formed to be larger as αa, αb, and αC as they move upstream, the opening degree of the dispersion holes on the upstream side increases, and each dispersion hole The amount of spray from the engine is the same at the rotational speed at that time. Moreover, since air is supplied into the inner cylindrical body 27 from the air supply pipe 33, the inside of the inner cylindrical body 27 is always maintained at a positive pressure, and the powder can be more reliably spread from the dispersion holes 31a to 310, etc. .

〔Effect of the invention〕

The present invention has a dispersion section that disperses powder into the mold.
An inner cylindrical body having an open tip and a plurality of dispersion holes formed in the cylindrical part, and an outer cylindrical body having a substantially trapezoidal slit that changes the opening area of each dispersion hole. As the slit goes upstream, the trapezoid's opposing side angle becomes larger, and the air supply pipe is connected to the inner cylinder, so when the rotation speed of the spring feeder is changed and the outer cylinder is rotated, It is possible to change the area of the total spray holes and the amount of spray. At that time, the same amount of powder is sprayed from all the spray holes.

Therefore, the desired amount can be evenly distributed and sprayed onto the molten steel surface, and the prescribed cooling and WIJ sliding effects can be exerted without interruption.

〔Example〕

Hereinafter, the present invention will be explained in detail based on examples thereof.

FIG. 1 is an overall view of a powder supply device, which is applied to continuous casting equipment that continuously casts billets and the like. A continuous casting machine is a mold ■ and a mold 1 in which molten liquid 12 is charged.
1% 3, a nozzle 4 for guiding the molten steel 2 from the bottom of the ladle 3 to the mold 1, a metal fitting 5 for connecting the nozzle 4 and the ladle 3, and, although not shown, pulling out the solidifying billet from the mold 1. It consists of pinch rollers and a cooling device that cools the billet.

The device for supplying the powder 6 for oxidation prevention and lubrication of the molten [2A] into the mold 1 includes a vertical pipe 7, a reservoir 8, a spring feeder 9 whose rotation speed can be changed, and a It has a dispersion part IO formed at the tip. In this example, a hopper 11 containing powder 6A is carried onto the second floor 12 by a crane or the like and installed on a platform 12a. A cut-out bag W14 is connected. The device 14 for cutting out a fixed amount of powder is driven by the rotation of a motor 15 being transmitted through a sprocket and a chain. That is, the spring feeder 16, which has a spiral spring built into its tube body,
A fixed amount of powder under the expansion joint 13 is cut out and conveyed.

Since the powder needs to be conveyed to the opening of the mold 1 at a different height from the lower end of the hopper 11, a vertical pipe 7 is installed directly below the outlet 16a of the spring feeder 6.
is located. Vertical pipes are shown in Figures 3 (a) and (b).
For example, two vertical pipes are provided as shown in the figure, and each vertical pipe?
A bifurcated duct 17 is interposed at the upper end of each of A and 7B, and the moving direction of the powder can be changed by a built-in damper 18. This is to keep the height of the powder in the reservoirs 8A, 8B connected to the lower ends of each vertical pipe within a certain range. The vertical pipe 7 for dropping powder into the reservoir 8 is a flexible pipe made of, for example, nylon, and can be easily connected to and removed from the reservoir 8. A plurality of chains 19 are suspended within the vertical tube 8 and attached to a hanging support 20. The suspension member 20 is rotated by the power of a motor 21 (see FIG. 1) via a sprocket 22 (see FIG. 3(a)). The &119 is used to prevent powder from adhering to the inside of the vertical tube 7 and from growing and causing bridges, and the deformable one is used for the vertical tube. This is to ensure that when the vertical pipe 7 is evacuated, the vertical pipe 7 is not obstructed by being inside the vertical pipe 7.

Two rows of spring feeders 9 are provided below the reservoir 8, and the spring feeders 9 and the reservoir 8 constitute a feeder 23 that supplies powder to the mold 1. The spring feeder 9 is driven by the rotation of a motor 24 (see FIG. 1) being transmitted through sprockets 25 and 26.
The powder in the storage container 8 is continuously carried out in fixed amounts. Note that when increasing or decreasing the supply amount to mold 1, motor 2
4 rotation speed can be changed. The reason why two spring feeders 9 are provided as shown in FIG. 4 is that the dispersion portion at the tip of the spring feeder 9 is provided in a plan view so that the supply to the molten steel surface is uniform around the nozzle 4. 10 is nozzle 4
This is because it is necessary to arrange them facing each other so as to sandwich them. By the way, the scattering section 10 is provided with, for example, 4 (Ii) scattering points, and approximately the same amount of powder is spread from all the points.Therefore, in this example, there are 8 scattering points on the molten steel surface. As a result, the powder is evenly distributed around the nozzle 4, and enough powder is always supplied to thinly cover the f614 surface.

By the way, the dispersion section 10 is composed of an inner cylinder body 27 and an outer cylinder body 28, and as shown in FIG. It is formed. In this example, three dispersion holes 31 are provided, all of which have the same width, for example, but whose lengths can be changed.In other words, the outer cylinder body 28 has holes for changing the opening area of the dispersion holes 31. A substantially trapezoidal slit 32 is formed, and as shown in the slit development diagram in FIG. .

αC and ``ζ'' are formed in order of increasing size.Then, the internal body 2
7 incorporates a rotating spring up to the opening 29, and the outer cylinder body 28 rotates while surrounding the inner cylinder body 27, so that the opening of the dispersion hole 31 is limited to the width of the slit 32. The area of the dispersion hole 31 can be set to a desired size according to the rotation of the outer cylinder 28.

The selection of the included angles of the opposite sides of the trapezoid varies depending on the diameter of the inner cylinder 27, the wire diameter and pitch of the spring, the distance between the spray holes, etc., but once these are specified, the rotation speed of the spring feeder can be determined. The application rate is determined depending only on
The inventors' research has confirmed that the amount of spray from the opening 29 and each spray hole 31 is equal. For example, while the rotation of the spring feeder 9 is kept constant, the areas of the spray holes 313 to 31C provided at desired intervals are changed until the spray portions from each of the holes including the opening 29 are equal, and the area of each spray hole during that rotation is changed. The area was measured. The rotational speed of the spring feeder 9 was changed, and the area of the spray hole for the same amount of spraying at that rotational speed was measured. Incidentally, when the dispersion holes have the same opening area, the amount of dispersion is the largest at the opening 29 at the tip, and the amount of dispersion gradually decreases as the powder is moved upstream of the powder conveyance path. The above-mentioned trapezoidal slit is intended to eliminate the difference in the amount of spray as much as possible.

Once the diameter of the dispersing portion 10 is determined, it is not easy to change the opening area of the opening 29, so it is assumed that it remains unchanged, and when examining the change in the hole area with respect to the rotation speed for each of the dispersing holes 313 to 31c, it is found that the above-mentioned outer cylinder body 28 This results in a geometric shape that looks like it was formed in . Therefore, if the hole width of the spray hole is kept constant, and the hole length is changed by the slit 32, the same amount of spray can be obtained at each rotation speed.

Incidentally, it is necessary that the powder is always smoothly dispersed from each of the dispersion holes 31a to 31C, and in order to reliably maintain this, an air supply pipe 33 is attached to the inner cylindrical body 27. This is connected to an air source (not shown), and the inner cylinder body 2
Care has been taken to maintain positive pressure inside 7 at all times. Of course, it is preferable that the pressure is at a level that does not cause the powder to generate dust, but it is convenient to select the air pressure so that it can be changed depending on the particle size and properties of the powder.

The operation of the powder supply device to the mold for a continuous casting machine having such a configuration will be described next.

A large amount of powder 6A is stored in a hopper 11 installed on the second floor 12, and the powder is deposited in a certain amount of powder cutting device 14 via an expansion joint 13 due to the rotation of a spring in a spring feeder 16. It is cut out in quantitative order. When the rotational speed of the motor 15 is set high, the fixed amount of cutout increases. Its speed is controlled by a control signal from a separate command center. The powder that has reached the discharge port 16a at the tip of the spring feeder 16 is introduced into the bifurcated duct 17 and falls into one vertical pipe 7 according to the damper 18. The powder that has been cut into a fixed amount and transported is transferred to a storage container 8 so as to fall through a vertical pipe 7. The damper 18 is switched in response to a signal from the level sensor 34 attached to the reservoir 8, and the powder in the reservoir 8 is kept at a substantially constant layer height. The spring feeder 9 is driven by the motor 24, and a fixed amount of powder depending on the rotation speed of the spring feeder 9 is horizontally conveyed to the spraying section 10. Powder is dispersed from the dispersion section 10 into the mold 1 from a total of four locations, the opening 29 at the tip and the dispersion holes 312 to 31c, and the powder is evenly dispersed onto the molten steel surface. In addition, the powder is incorporated into the molten steel so as to be mixed with the molten steel that is continuously introduced from the ladle 3, and prevents oxidation of the molten steel 2A and promotes slipping between the molten steel that has begun to solidify and the mold 1, and deformation. be done.

On the other hand, in the vertical tube 7, the chain 19 hangs down from the suspension member 20 and is rotated, so that the powder that has been conveyed in a fixed amount is stimulated by the movement of the chain and is continuously transported without clogging the vertical tube 7. It falls into the reservoir 8. Therefore, phenomena such as bridging and clogging and falling defects are avoided, and a constant quantity of powder can be transferred in the vertical pipe 7, which is not easy to transport.

By the way, when you want to increase the amount of powder supplied,
The outer cylindrical body 28 of the dispersion section 10 is rotated, and the lengths of the dispersion holes 31 are lengthened by an amount corresponding to each of them. This is achieved by shifting the slit 32 toward the wider portion, and the width of the slit 32 is increased on the upstream side of the powder conveyance path. That is, since the slits are formed with different widths as shown in the developed view shown in FIG.
The rate of increase/decrease is different depending on a to 31b. However, since the rotational speed of the spring feeder 9 at that time is set so that the amount of powder to be spread from all the spreading points is approximately the same, there will be variations in the amount of powder spread from one spreading section 10. There are almost no such things. Further, since compressed air is supplied into the inner cylinder body 27, the positive pressure thereof helps spread the powder. In addition, the supply amount of powder is
It depends on the composition of the molten steel and the dimensions of the billet to be cast.
Even if the amount is changed within the range of 0%, the same amount of spraying can be obtained each time. As an example, the case of a 12VW pipe is shown in the table below, and it can be seen that almost the same amount of dispersion is achieved.

(The spray area is mn? The spray amount is g/win)

[Brief explanation of the drawing]

Fig. 1 is an overall view of the powder supply device of the present invention applied to continuous casting equipment, Fig. 2 is a layout of the dispersion holes, etc. in the dispersion section, and Figs. FIG. 4 is an enlarged front view and side view, FIG. 4 is a diagram showing the arrangement of the powder spraying section around the nozzle, and FIG. 5 is a developed view of the trapezoidal slit. T-mold, 2,2A-molten steel, 6.6A-powder, 7-vertical pipe, 8-reservoir, 9-spring feeder,
l〇-Spraying part, 27-Inner cylinder, 28-・Outer cylinder, 29-
Opening, 30-cylindrical part, 32-slint angle.

Claims (1)

[Claims] (1) The powder that has been conveyed in a fixed amount is dropped into a storage container through a vertical pipe, and the powder held at a predetermined layer height in the storage container is carried out by a spring feeder whose rotation speed can be changed. This is a powder supply device that scatters powder onto the molten steel surface of a mold for a continuous casting machine from a dispersion section provided at the tip, and the dispersion section has an open tip and a plurality of dispersion holes. The cylindrical portion includes an inner cylindrical body and an outer cylindrical body in which a substantially trapezoidal slit is formed to change the opening area of each of the dispersion holes. 1. A powder supply device for a mold for a continuous casting machine, characterized in that the corners are formed large and an air supply pipe is connected to the inner cylindrical body.