JPS63130256A - Ladle for molten metal - Google Patents

Abstract

PURPOSE:To remarkably reduce unit heat weight by equipments for melting, casting, etc., as compared with the standard without any reconstruction of the equipment by making the ratio of sectional area of bottom part to that of top part in the inner shape after refractory lining, the specific value. CONSTITUTION:The ratio of flat area SB at the bottom part to the sectional area ST at the top part after refractory lining is made to 0.01-0.50. By making SB/ST smaller, a ladle volume is made to reduce, but height (h) of ladle is the same height as the standard heat size (unit heat size). Ratio of upper surface area Sm of molten metal in the ladle to the height (h) of ladle (Sm/h) is maintained to the value fixed by the ladle refining method, and the volume of molten metal is made to smaller. By using this ladle, the heat size can be remarkably reduced without any reconstruction for the equipment, such as melting, etc., and the production of little lot with the just amount can be produced.

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention utilizes existing factory equipment such as metal melting, refining, and casting equipment with almost no modification, and reduces the unit weight of melting by these equipment. This invention relates to a ladle for molten metal whose heat size (hereinafter referred to as heat size) can be made significantly smaller than the standard.

<Prior art> A normal ladle for molten metal is made of metal, as shown in Fig. 9.
For example, fireproof materials 4a, 4 are placed inside the outer skin 1 of a steel Fi welded structure.
A molten metal storage section is formed by lining b, and a pouring nozzle 9 is provided at the bottom.

The internal volume of the ladle is determined by the furnace volume of a melting/refining furnace such as an electric furnace or a converter, and the method of secondary refining (ladle refining) in the ladle.

The gas bubbling method, vacuum suction degassing method (DH degassing method), and the reflux degassing method (R,H degassing method), which involve blowing a small amount of gas into a ladle and stirring, are used to melt the material into a vacuum container. In a ladle used for the method of sucking up and degassing metal, the molten metal may ooze out of the ladle due to shaking, boiling, or swelling of the molten metal in the ladle during gas stirring or degassing treatment. Since there is no danger, there is no need to increase the height from the surface of the still molten metal to the top of the ladle (hereinafter referred to as the freeboard), as described in the 3rd edition of the Steel Handbook ■Pigmaking/FI, page 574. Although the internal volume is determined primarily by the furnace volume, the heat size can vary by about ±5% depending on the amount of planned ingots or slabs. Generally, a new pot immediately after being lined with refractory material does not receive the maximum amount of hot water, but has a capacity that is approximately the average amount of hot water.

On the other hand, deoxidizing, desulfurizing,
When performing treatments such as adding alloys, or degassing the bath surface in the ladle (so-called ladle f1), the ladle used for the degassing method is used to prevent melting in the ladle during gas injection or during degassing. metal I
Eli J. Because there is a risk of molten metal leaking out of the ladle due to boiling or heaping, it is necessary to set the freeboard 11° larger than in the case of a general ladle. It is said that the freeboard hr needs to be about 40 to 50% of the static depth of the molten steel, and recently there has been a trend towards stirring by blowing in a large flow of gas. It reaches 40-100% of the static bath depth.

The longitudinal cross-sectional shape of the ladle after the outer skin and refractory lining is either cylindrical or oval cylindrical with a straight body (hereinafter referred to as straight type), or tapered so that the body is wide at the top. There is a shape that is a truncated cone or an inverted elliptical cone (hereinafter referred to as a tapered cone).

In general, compared to the straight type, the tapered type ■ has a larger contact area with the slag per unit weight of molten metal, ■ has irregular brick shapes and is difficult to construct, ■ trunnion spans (LT in Figure 9) and hook spans for ladle cranes. The taper of the side wall of the tapered ladle is not made very large because it has disadvantages such as: (1) the ladle manufacturing cost is high; Tables 1 and 2 show the results of calculations of the taper of the side wall iron skin of the tapered ladle from the data listed in the above-mentioned Steel Handbook, and it falls within the range of 40/1000 to 59/1000.

The ratio of the planar area of the bottom of the ladle to the cross-sectional area of the top of the body is 0.61 to 0.83 for tapered ladles, as shown in Tables 1 and 2, and for straight ladles. Approximately 1
．． It is 0.

By the way, when using existing related equipment with almost no modification to make the heat size significantly smaller than the standard, the following restrictions are imposed by the existing equipment.

■ Match the trunnion span L to the span of the hook of the ladle crane.

- Increase the outer distance of the support hardware 7 by a certain value or more than the distance between the seats 10 of various ladle support equipment.

■ The outside diameter DOA of the top of the ladle body (explanation in Figure 9) shall be compatible with the diameter Dtc of the ladle lid of various ladle refining equipment (see Figure 11).

■ When the ladle is supported by a ladle car or a ladle turret as a ladle support equipment of continuous casting equipment, the distance from the bottom of the ladle when the ladle is lowered to the lower limit position using the attached ladle lifting mechanism. The distance H and A (see Fig. 12) from the upper end of the tandem to the upper end is the maximum allowable value HL required for using the existing sealing device.

The following shall apply.

■ Inner dimension D1 at the top of the ladle body and the bath surface level.
．． DIs (see Figure 9) is greater than R) the outer distance of the immersion pipe of Type 1 degassing equipment (see Figure 13).

■ The surface level of the static molten metal bath in the ladle must be such that the existing RH type skin degassing equipment immersion tube can be immersed in the ladle-shaped metal bath to a certain level of cleanliness.

Now, in order to make the heat size smaller than before, there is the following method.

(al Method of reducing the filling rate of molten metal, ~) Method of reducing the inner volume of the ladle (b.1) Thickness T of the bottom refractory
(b.2) Method of making the ladle shallower by raising the bottom plate.

However, in the fal method, when applying the RH skin degassing method (D) I degassing method described in (1) above or the ladle refining method using three-phase electrode arc heating, the heat size cannot be reduced very much. Furthermore, if the freeboard is larger than necessary, the heat loss to the freeboard portion during various ladle refining operations will be significantly greater than in the case of standard size, resulting in a large temperature drop during refining and a decrease in heating efficiency. Furthermore, the basic unit of ladle refractories increases.

In method (b-1), the ladle nozzle hole becomes long, and the nozzle hole is likely to become clogged at the start of pouring or during pouring.

Further, when the nozzle hole is blocked, it becomes extremely difficult to clean the nozzle hole with an Oz lance and to replace the nozzle brick.

In method (b.2), when using existing continuous casting equipment,
In order to keep the distance from the bottom of the ladle to the end of the tundish, . Also, the heat size cannot be reduced much because it cannot be reduced below a certain value. If I+ is made smaller than a certain value, it will be necessary to prepare a sealing device for the injection flow between the ladle, tandy, and cup (not shown in Fig. 12) of 21 class or more, which will not only be complicated in operation, but also As the distance between the ladle and the tandinosh increases, adverse effects occur due to the scattering of the resident flow, melting of the refractory due to the collision of the injected flow with the refractory at the bottom of the tandish, an increase in shells, and melting of the tundish of the refractory proboscis and melting within the shell. Contamination with metals causes increased staining.

<Problems to be Solved by the Invention> The present invention solves the following problems within the limits of the above-mentioned ■ to ■ regarding the external shape and dimensions of the ladle and the internal shape and dimensions after being lined with refractory material.
The previously considered ia1. (According to the BL method, there were disadvantages in that the heat size could not be reduced below a certain limit, and even if it could be reduced, it would cause operational, economic, or quality problems, so these disadvantages were overcome. However, this was done in order to provide a number i1i for molten metal which can be significantly smaller than the standard heat size, for example, 509% or less of the standard heat size.

The present inventor has conducted extensive research on a method of reducing the heat size by utilizing the existing film D1η as is, and found that
) We have found that this can be achieved by devising the shape of the ladle for molten metal after it is lined with refractory material, and based on this knowledge, we have accomplished the present invention.

The present invention is a ladle for molten metal whose internal shape after refractory lining has a ratio of the bottom plane area to the cross-sectional area of the top of the body of 0.01 to 0.50.

<For production> The configuration of the present invention will be explained with reference to FIG.

First, the symbols in the figure will be explained below. S = cross-sectional area of the top of the ladle after lining with refractory material, S: bottom area of the ladle after lining with refractory material, S8: surface area of the top surface of molten metal in the ladle, h: Cancelled internal height after refractory lining, h, 4; (in ladle) molten metal static height, ■L = Ladle internal volume after refractory lining, vL4: Molten metal volume in ladle, Now , S, /ST from 1.0 to 0.90.0.80.
-1---=0.10.0.05,0.01. and vL and V when l+14/h was changed to 0.90°O, SO-1.-0.50.

as a function of h and S, V, = k −h −sr −−−−・・−・
(1) v, =, 4- h -St -・-(2
), and the values of k and kH are expressed as S, /S.

Table 3 shows the results calculated for the values of 4/h.

In the present invention, the internal volume of the ladle is reduced by reducing S, /SA, the internal height h is the same as that of the standard heat size, and h, /h is maintained at the value determined by the ladle refining method. At the same time, the volume vM of the molten metal is reduced. Here, ■ When applying the R11 type degassing method or the D11 type degassing method, it is normal to maintain the bath level so that the immersion tube is immersed in the metal bath in the ladle to a certain depth or more. /h≧0
．． 8. ■ When applying other ladle degassing methods,
The freeboard is 40% to 100% of the static bath height, i.e. (h − hs ) / hq = 0.40 to 1.0 → h
=1.4~2. Oh, -hM/h=0.71~0.50
, L+/h is determined from .

From Table 3, 5. When /SA is set to 0.01 to 0.50, the conventional straight ladle, that is, Sm/St #
Original molten steel volume VMI when 1.0. The ratio of the molten steel volume VM11 after reduction to □/VMIO is as shown in Table 4. I/h=0. s ~0.9 (7
) if V, , /V,4+.

= 0.255 to 0.710, and the heat size can be reduced to 26 to 71% of the standard value.

mata, hs/h= 0.5~0.70) V, l*/
VM+e = 0.123 to 0.659, and the heat size can be reduced to 12 to 66% of the standard value.

From Table 3, when SII/St is set to 0.01 to 0.50, the conventional tapered ladle, i.e., SII
/S? Original molten steel body f when =0.8.0.7.0.6
itv i. ,.

■MO? + ν9゜6. molten steel volume after reduction to ■.

The ratio of V+<x/V*os, Vn*/\sot, VM
II/VMO& are calculated as shown in Tables 5, 6, and 7, respectively.

From Table 5, the conventional tapered ladle Sn, 'Sr = 0
．． SII/ST = 0.01~ compared to that of 80
By setting it to 0.50, V, 4*/VPae =
0.144 to 0.800, that is, the heat size can be reduced to 14 to 80% of the standard, and from Table 7, S++/
Even when compared to the case where the ratio is originally small, ST = 0.60, V□/VM. , = 0, 177-0.921, that is, it becomes possible to reduce the heat size to 18-92% of the standard.

The reason why Sl/ST =0.01 is used as the lower mold in the present invention is as follows.

As can be seen from Tables 4 to 7, s,,'s□-〇,01
In the case of 5s/S↑=1.0, that is, up to 12 to 31% of the standard compared to the straight ladle, the conventional Sl
/ST = 0.6~0.8 The heat size can be reduced to 14~40% of the standard compared to a tapered ladle, which is almost sufficient considering industrial needs, and 5s/S
When ↑ = 0.1, the bottom inner diameter/top inner diameter = diameter is 10% of the top inner diameter, and the bottom inner diameter is 1 for the top inner diameter of 4450 mm of the ladle with the maximum volume g3oot shown in Table 2.
/10, it becomes 445 ■ severe, and this value is the minimum value required for constructing the bricks around the nozzle, that is, the practical limit for constructing the refractory material including the bottom nozzle. This is also possible because if the bottom area becomes too small, there is a risk that the molten metal near the bottom will solidify or the nozzle will become clogged, making it impossible to inject the molten metal.

<Example> Fig. 2 tal - (bl, Fig. 3 (al -ffi+ and Fig. 4 fa) - (bl is a longitudinal section and perspective view showing an embodiment of the present invention. These embodiments Now, for the external structure and dimensions of the ladle, including the outer skin l of the ladle, for example, the external shape and dimensions of the trunnion 5, the upper and lower stiffeners 68, 6b, or the supporting hardware 7, the existing ones may be used as they are, or the existing ones may be used. By making the ladle external shape and dimensions the same as that of the existing equipment, for example, ■ Making the trunnion span LT match the funk span L of the one-dollar crane, ■ Making the ladle support hardware 7a, 7b The outer distance LR is set to be larger than the distance MLs between the seats (stands) 10 of various ladle support equipment by a certain value; ■ The outer diameter DO'r of the top of the ladle body is the same as that of the ladle of various ladle refining equipment. The diameter of the lid shall be compatible with DLC. ■ If the ladle support equipment of continuous casting equipment is supported by a rolling machine or a rolling machine, the attached lifting mechanism shall be compatible with the diameter of the lid. ILf (distance from the bottom of the ladle to the upper end of the ladle when the ladle is lowered to the lower limit position) must be less than or equal to the maximum allowable value (11!H+, t.) necessary for using the existing sealing device, etc. Satisfied. Next, consider the constraints of other equipment (mainly ladle refining equipment) on the internal shape and dimensions after refractory lining, such as: ■ Internal dimensions Dlr at the top of the ladle body and bath surface level.
, Dls is the outer distance Lr of the immersion pipe of the R8 type degassing equipment
■ The molten metal stationary bath level in the ladle must be such that the immersion pipe of the existing R8 type degassing equipment is immersed in the slag in the ladle to a certain depth or more; These conditions are satisfied by making the inner diameter Dh of the top after refractory lining, the internal height h of the ladle, and the height of the metal static bath in the ladle the same as those of the existing Enoki semi-ladle.

In Figure 2 ta+ - (bl, Figure 3 (al - (bl), the shape of the torso outer skin is a wide tapered type that is the inverse shape of a cone with a truncated head. The top cross section of the bottom area S after refractory lining may be the opposite shape of an elliptical cone, i.e., it may be a wide tapered type with an elliptical cross section, or it may be cylindrical or an elliptical straight type. In order to set the ratio 5dSr to the surface area S = 0.01 to 0.50, in the embodiments shown in Figs. 1 to 3, a metal inner wall 2 is provided inside the outer skin 1, and as shown in Fig. A side wall refractory material 4a is lined inside the metal inner wall 2 or as shown in FIG. 3.

The inner surface shape of the body may be an inverted oblique cone with a truncated head as shown in Figure 2, or an inverted cone with a truncated head as shown in Figure 3. good. That is,
The nozzle position at the bottom of the ladle may be appropriately selected so as to be included in the bottom surface. In addition, as shown in Fig. 4 (tar/mountain), the shape may be selected as required, such as a shape that looks like inverted cones with a truncated top stacked in two layers.

Figure 5 (fat middle) shows another embodiment of the present invention, but in this example, unlike the embodiments in Figures 2 to 4, the inner wall 2 is not provided, and a metal filling body The ratio of the bottom area S, after refractory lining, to the top cross-sectional area S, S, /S
T, -0.01 to 0.50.

FIG. 6(a) shows another embodiment of the present invention. In this example, the inner wall 2 as in the embodiments in FIGS. SB/St = 0.01 to 0.50 by directly lining the inside of the outer skin 1 with a thick side wall 4a without attaching a metal filler 3 such as the one shown in FIG.

FIG. 7(a), crest) and FIG. 8+a+, 11 are a longitudinal sectional view and a perspective view showing another embodiment. In these embodiments, the external shape and dimensions of the ladle external structure including the ladle outer skin 1, such as the trunnion 5, the upper and lower stiffeners 6a, 6b, or the supporting hardware 7, are different from the existing ladle external shape. It is designed to satisfy the constraints imposed by the equipment, for example, the above-mentioned items 1 to 2. However, the shape of the torso outer skin,
The side wall refractories 4a are directly lined inside the outer skin 1, and the bottom area S is 0.10 to 0.71 with respect to the top diameter. The ratio Ss/Sy of # is set to 0.01 to 0.50.

Incidentally, in the above embodiments, the problems caused by increasing the taper of the side wall of the tapered ladle can be solved by the following methods.

■ Since the contact area of the bath tJA with the slag is larger than that of a straight ladle, rephosphorization from the slag is likely to occur in the presence of oxidizing slag, but the application of technology to prevent slag outflow from the converter, This problem can be solved by improving the basicity of the slag in the ladle and diluting and lowering the phosphorus and T-Fe concentrations in the slag.

■ The irregular shape of the bricks makes construction difficult and time-consuming, and there is a risk of leakage of molten metal from the joints of the bricks, but this was resolved by using a method of constructing the sidewall wear lining with monolithic refractory material. can.

<Effects of the invention> The present invention can be used without modifying existing melting/refining furnaces such as electric furnaces and converters, various ladle refining equipment, continuous casting equipment, ladle transportation support equipment such as ladle cranes and ladle cars, etc.
In addition, it does not require special auxiliary means, equipment, or working methods different from the standard melting unit (heat size) of the molten metal ladle of the melting/refining furnace or ladle refining equipment, and the heat size significantly smaller than the standard, e.g. 50% or less of 52,
It becomes possible to reduce the size to a minimum of about 12 to 40%. In addition, other means to reduce the heat size,
For example, if the ladle internal volume is kept as it is, the filling rate is lowered and the freeboard is increased, (al ladle refining process becomes impossible) and (b) the temperature drop of the molten metal in the ladle is reduced. There are no problems such as an increase in the C1 refractory unit consumption, no operational troubles such as nozzle clogging associated with other methods, and no problems such as quality deterioration of molten metal.

In addition to the standard size ladle, by providing one or more types of ladle for molten metal for small heat size according to the present invention with different internal volumes, it is possible to replace the conventional standard size ladle. Now, it becomes possible to produce small loft-sized orders, which were previously impossible to produce, using existing equipment and processes, without excess or deficiency, or while suppressing surplus production to the minimum amount.

[Brief explanation of the drawing]

Figure 1 (al-(bl) is a perspective view explaining the present invention in detail, Figure 2 (al-(bl), Figure 3 (al-11,
Figure 4 (al - fbl, Figure 5 fat Q)l, Figure 6 (al - (bl, Figure 7) (al - (bl, Figure 8
Figures +a+ and ('b) are longitudinal sectional views and perspective views showing embodiments of the present invention, Figure 9 is a partially sectional front view of the ladle, and Figures 10 (ai and (b) are of the receiving cart). A front view and a side view, FIG. 11 is a partially sectional front view illustrating a ladle refining furnace using the Radolfa-2S process, and FIG. 12 is a sectional view illustrating air seal equipment between the ladle and tundish. Figure 13 shows R
It is a sectional view of LI type degassing equipment. 1a... Metal outer skin (body) 1b... Metal outer skin (bottom) 2... Metal inner wall 3... Metal filling body 4a... Refractory material (side wall) 4b... Fireproof Items (bottom) 5... Trunnion shaft 6a... Upper stiffener 6b... Lower stiffener 7... Support hardware 8... Support hardware 9... Pouring nozzle 10... Ladle holder Seat (receiving cart) 11...Ladle receiver (CC one dollar car) 12...Ladle 13...Hanging beam 14...Hook 15...Ladle insulation lid 16...Receiver Mouth truck 20... Ladle furnace furnace M 21... Graphite electrode 22... Alloy hopper 23... Ladle truck 24... Porous plug 25... Sliding nozzle 26... Molten steel 27 ... Arc 31 ... Electromagnetic induction stirring device 32 ... Tundish 33 ... Seal cover 34 ... Seal material 35 ... Argon gas 36 ... Injection flow 37 ... Vacuum degassing container 38a...Immersion pipe (rising pipe) 38b...Immersion pipe (lower pipe) Patent applicant Kawafi Steel Co., Ltd. Fig. 1 (a) (b) Fig. 2 (a) (I)) Fig. 3 (a) (b) Figure 4 (a) (b) Figure 5 (a) (b) Figure 6 (a) (b) Figure 7 (a) (b) 5B Figure 8 (a) ( b) T Figure 9 Figure 1O (a) (b) Figure 11 Figure 12

Claims (1)

[Claims] A ladle for molten metal, characterized in that the internal shape after lining with refractory material has a ratio of the flat area of the bottom to the cross-sectional area of the top of the body of 0.01 to 0.50.