JP2017196642A - Frame mold for molten steel ladle, construction method for molten steel, and molten steel ladle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molten steel ladle frame mold capable of reducing the residual steel quantity over a long term, a construction method of a molten steel ladle, and a molten steel ladle.SOLUTION: A frame mold 7 is used when a ware refractory product 4 is lined on the inner side of a molten steel ladle 1. The molten steel ladle 1 is formed, on the side face of the lower end side to become the bottom of the molten steel ladle 1 (the bottom 22 of an outer shell 2) in the vicinity of a tuyere 5, with a notch part 71 for forming a ramp 411 of the molten steel ladle 1 lowering toward the side wall portion (the side wall part 21 of the outer shell 2) of the molten steel ladle 1.SELECTED DRAWING: Figure 5

Description

  The present disclosure relates to a mold for a molten steel pan, a construction method for the molten steel pan, and a molten steel pan.

  Since a molten steel pan (ladder) used in steelworks or the like accommodates molten steel, a refractory is lined (lined) inside. Such refractories include a permanent refractory lined on the outer shell, and a wear refractory lined inside the permanent refractory. Of these, the wear refractory is in direct contact with the molten steel and melts down, so that the wear refractory is frequently replaced as compared with the permanent refractory. The ware refractory is made of an indeterminate refractory in a laying part or a wall part that comes into contact with molten steel, and is constructed using, for example, a formwork described in Patent Document 1.

In the steelmaking process at the steelworks, the molten steel accommodated in the molten steel pan is refined and then cast to produce semi-finished steel products such as slabs, blooms and billets. When the molten steel is cast, the discharged molten steel is cast by discharging the molten steel from the tuyere provided at the bottom of the molten steel pan in a casting facility such as a continuous casting machine. However, if casting is performed in a state where the bottom of the molten steel pan is flat, the remaining steel amount, which is the amount of molten steel remaining in the molten steel pan after the end of casting, increases, which causes a reduction in manufacturing yield.
For this reason, an irregular shaped refractory is further applied to the upper surface of the bottom of the ware refractory so that an inclined part is formed in the vicinity of the tuyere of the molten steel casserole with the ware refractory applied. Lining in is done.

JP-A-10-216924

However, as described above, when the irregular refractory is further lined on the upper surface of the bottom of the wear refractory to form the inclined portion, the irregular refractory in the inclined portion is lined on the cured ware refractory. (Cold joint). In this case, the joint part (cold joint part) between the wear refractory and the inclined object is weak in the joint strength, and thus is easily worn away by peeling. By repeating the steel receiving and receiving the molten steel in the molten steel pan, The problem is that the effect of reducing the amount of remaining steel by the inclined portion cannot be obtained.
Then, this invention is made paying attention to said subject, and provides the form of the molten steel pan which can reduce the amount of remaining steel over a long period of time, the construction method of a molten steel pan, and a molten steel pan. It is aimed.

  According to one aspect of the present invention, the mold is used when lining a ware refractory inside the molten steel pan, and has a cylindrical shape extending in the height direction of the molten steel pan, On the side surface on the lower end side that is the bottom side of the molten steel pan, a notch portion that forms an inclined portion of the molten steel pan that falls from the side wall portion of the molten steel pan toward the tuyere in the vicinity of the tuyere of the molten steel pan. A form of a molten steel pan is provided.

  According to one aspect of the present invention, when a ware refractory is lined inside the molten steel pan, it has a cylindrical shape extending in the height direction of the molten steel pan, and becomes the bottom side of the molten steel pan. Using a mold having a notch on the side surface on the lower end side, lining the wall portion of the wear refractory having an inclined portion that falls from the side wall portion of the molten steel pan toward the tuyere, and the wall portion is After lining, the construction method of the molten steel pan characterized by lining the above-mentioned wear refractory laying part inside this wall part is provided.

  According to one aspect of the present invention, the wear refractory includes a bottomed cylindrical outer shell, a wear refractory lined inside the outer shell, and a tuyere provided at the bottom of the outer shell. Has a wall portion lined on the side wall portion of the outer shell and a lining portion lined inward of the wall portion at the bottom portion of the outer shell, and the wall portion is integrated with the wall portion. There is provided a molten steel pan formed and having an inclined portion that falls from the side wall portion toward the tuyere in the vicinity of the tuyere.

  According to one aspect of the present invention, there is provided a mold for a molten steel pan, a construction method for the molten steel pan, and a molten steel pan capable of reducing the amount of remaining steel over a long period of time.

It is a top view which shows the molten steel pan concerning one Embodiment of this invention. It is the II sectional view taken on the line of FIG. It is sectional drawing which shows the molten steel pan constructed using the construction method of the conventional molten steel pan. It is explanatory drawing which shows the construction method of the conventional molten steel pan. It is explanatory drawing which shows the construction method of the molten steel pan which concerns on one Embodiment of this invention. It is sectional drawing which shows the state of the molten steel pan at the time of casting in a modification. It is a top view which shows the molten steel pan constructed using the construction method of the molten steel pan in a modification. It is the II-II sectional view taken on the line of FIG. It is sectional drawing which shows the molten steel pan constructed using the construction method of the molten steel pan in a modification.

  In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. However, it will be apparent that one or more embodiments may be practiced without such specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.

<Composition of molten steel pan>
First, with reference to FIGS. 1 and 2, the structure of the molten steel pan 1 according to an embodiment of the present invention will be described. The molten steel pan 1 has a bottomed cylindrical shape, and includes an outer shell 2, a permanent refractory 3, a wear refractory 4, and a tuyere 5.
The outer shell 2 is an iron shell, and is a container having a substantially cylindrical side wall portion 21 and a bottom portion 22 that covers an opening at the lower end of the side wall portion 21 (the lower end with respect to the paper surface of FIG. 2).
The permanent refractory 3 is a refractory having a predetermined thickness and is lined inside the outer shell 2 excluding the position of the tuyere 5. The permanent refractory 3 may be formed of a regular refractory or may be formed of an indeterminate (castable) refractory.

The wear refractory 4 is lined inside the permanent refractory 3 and includes a wall portion 41, a laying portion 42, and a slag line portion 43.
The wall portion 41 is formed of an irregular refractory, and is lined with a predetermined thickness on the permanent refractory 3 provided on the side wall portion 21 except for the upper end side of the side wall portion 21. The wall portion 41 is formed from the permanent refractory 3 provided on the bottom portion 22. Further, as shown in FIG. 1, the wall portion 41 has an inclined portion 411 formed so as to fall from the side wall portion 21 toward the tuyere 5 near the tuyere 5. Details of the position where the inclined portion 411 is formed will be described later.

  The laying part 42 is formed of an irregular refractory, and is lined with a predetermined thickness on the permanent refractory 3 provided on the bottom part 22. The laying part 42 is formed inside the wall part 41 so as to cover the opening at the lower end of the wall part 41. Furthermore, the upper surface of the laying portion 42 is inclined so that the height of the upper surface (the upper surface with respect to the paper surface of FIG. 2) where the tuyere 5 is provided is relatively low on the upper surface of the laying portion 42. Provided. In the present embodiment, the slope of the laying portion 42 is formed so that the height of the upper surface decreases along the x-axis direction of FIG. Note that the x-axis direction and the y-axis direction in FIG. 1 are horizontal directions orthogonal to each other.

  Here, the position in the vicinity of the tuyere 5 where the inclined portion 411 of the wall portion 41 is formed will be described in detail. As described above, when the molten steel is cast using the molten steel pan 1 having the bottom portion 22 provided with the slope on the upper surface, the height of the upper surface of the bottom portion 22 is low as shown in FIG. Molten steel accumulates on the x-axis negative direction side. Although it is possible to reduce the amount of remaining steel only with the configuration in which the upper surface is provided with an inclination, an additional inclination is provided in a region where the height of the upper surface is equal to or lower than the position where the tuyere 5 is provided. Thus, the amount of remaining steel can be further reduced. Such a region is a region on the x-axis negative direction side from the tuyere 5 shown in FIG. 1 or a region on the y-axis negative direction side where the positions of the tuyere 5 and the x-axis direction are approximately the same. In the present embodiment, such a region is referred to as the vicinity of the tuyere 5. In the present embodiment, the amount of remaining steel can be reduced by forming the inclined portion 411 at a position including such a region.

The slag line portion 43 is formed of a regular refractory and is lined on the upper side of the wall portion 41 of the permanent refractory 3 provided on the side wall portion 21.
The tuyere 5 is a hollow cylindrical shaped refractory. Further, an upper nozzle, a sliding nozzle, and the like are provided on the outer surface side (lower surface side) of the bottom portion 22. Molten steel accommodated in the molten steel pan 1 is discharged through the tuyere 5.

<Construction method of molten steel pan>
Next, the construction method of the molten steel pan 1 which concerns on one Embodiment of this invention is demonstrated. First, prior to the construction method of the present embodiment, a conventional molten steel ladle 1a and its construction method will be described with reference to FIGS.
As shown in FIG. 3, a conventional molten steel ladle 1a includes an outer shell 2a, a permanent refractory 3a, a wear refractory 4a, a tuyere 5a, and an inclined portion 6. Among these, the outer shell 2a, the permanent refractory 3a, and the tuyere 5a have the same configuration as the molten steel pan 1 in the present embodiment.

  The wear refractory 4a is lined inside the permanent refractory 3a, and includes a wall portion 41a, a laying portion 42a, and a slag line portion 43a. The laying part 42a is formed of an irregular refractory, and is formed so as to cover the permanent refractory 3a provided on the bottom 22a. Moreover, the inclination is formed in the upper surface of the wear refractory 4a similarly to the molten steel pan 1 in this embodiment. The wall 41a is formed of an irregular refractory, and is lined with a predetermined thickness on the permanent refractory 3 provided on the side wall 21a except for the upper end side of the side wall 21a. Moreover, the wall part 41 is formed from the laying part 42a. In addition, unlike the molten steel ladle 1 of this embodiment, the inclined part 411 is not formed in the side wall part 21a. The slag line portion 43a is formed of a regular refractory material and is lined on the upper side of the wall portion 41a of the permanent refractory material 3a provided on the side wall portion 21a, similarly to the molten steel pan 1 of the present embodiment.

  Although the inclination part 6 is the inclination provided in the same position as the inclination part 411 of the molten steel pan 1 in this embodiment, the inclination with respect to a horizontal direction is formed gently. Moreover, in the molten steel pan 1 in this embodiment, although the inclined part 411 is comprised integrally with the wall part 41 of the wear refractory 4, in the conventional molten steel pan 1, it spreads on the spread part 42a of the wear refractory 4a. It is formed in a state of being cold jointed with the portion 42a.

In such a molten steel ladle 1a, the wear refractory 4a is lined in the steps shown in FIGS. 4 (A) to 4 (D). First, as shown in FIG. 4A, the state where the permanent refractory 3a is lined on the inner surface of the outer shell 2a is the state before construction.
Next, as shown in FIG. 4 (B), an unshaped refractory serving as a laying portion 42a of the wear refractory 4a is poured onto the permanent refractory 3a on the bottom 22a side, and then the laying portion is cured by drying. 42a is lined. At this time, the bottom 22a is inclined so that the height of the upper surface on the tuyere 5a side is lowered. Then, after the laying portion 42a is lined, the tuyere 5a is provided.

  Further, as shown in FIG. 4C, a mold 7a is provided inside the outer shell 2a and the permanent refractory 3a. Then, an irregular refractory material that becomes the wall portion 41a of the wear refractory material 4a is poured between the mold 7a and the permanent refractory material 3a, and then the wall portion 41a is lined by being cured by drying. The mold 7a has a substantially cylindrical shape extending from the laying portion 42a of the wear refractory 4a in the height direction of the outer shell 2 (upward with respect to the paper surface of FIG. 4). The mold 7a includes a material such as metal so that it can withstand the weight of the amorphous refractory to be poured. The formwork 7a may be provided with a beam (not shown) inside, and may be provided with a foamed plastic on the surface so that it can be easily removed from the hardened amorphous refractory.

  Thereafter, as shown in FIG. 4D, the mold 7a is removed. And the slug line part 43a is respectively lined on the permanent refractory 3a in which the inclination part 6 and the side wall part 21a of the upper end side are not formed in the bottom part 22a near the tuyere 5a. The inclined portion 6 is lined by providing an irregular refractory by hand so as to have a predetermined inclination, and then curing by drying.

The wear refractory 4a of the molten steel ladle 1a is constructed through the steps shown in FIGS. 4 (A) to 4 (D).
Next, with reference to FIG. 5 (A)-FIG. 5 (D), the construction method of the molten steel pan 1 which concerns on this embodiment is demonstrated. First, as shown in FIG. 5A, the state in which the permanent refractory 3 is lined on the inner surface of the outer shell 2 is the state before construction, as in the prior art.

  Next, as shown in FIG. 5B, a mold 7 is provided inside the outer shell 2 and the permanent refractory 3. Then, an amorphous refractory serving as the wall 41 of the wear refractory 4 is poured between the mold 7 and the permanent refractory 3, and then the wall 41 is lined by curing by drying. The mold 7 has a substantially cylindrical shape extending from the bottom 22 in the height direction of the outer shell 2. Moreover, the notch part 71 is formed in the side surface of the lower end side used as the bottom part 22 side in the state in which the formwork 7 was provided in the inner side of the outer shell 2 and the permanent refractory 3. The notch portion 71 is formed so as to fall from the side wall portion 21 of the outer shell 2 toward a position where the tuyere 5 of the bottom portion 22 is provided. Furthermore, the mold 7 has a vibration device 72 that vibrates the mold 7 on the inner peripheral surface. The configuration of the mold 7 other than the above, such as the presence or absence of beams, is the same as that of the conventional mold 7a. In this embodiment, it is preferable to vibrate the mold 7 by driving the vibration device 72 when the amorphous refractory is poured between the mold 7 and the permanent refractory 3. As a result, the irregular refractory is surely filled up to the space on the notch portion 71 side, so that the inclined portion 411 can be reliably formed.

Further, as shown in FIG. 5 (C), the mold 7 is removed. Then, on the permanent refractory 3 on the bottom 22 side, an irregular refractory serving as a laying portion 42 of the wear refractory 4 is poured, and then the laying portion 42 is lined by curing by drying. At this time, the bottom portion 22 is inclined as in the conventional method of FIG. After the laying part 42 is lined, the tuyere 5 is provided.
Thereafter, as shown in FIG. 5D, the slag line portion 43 is lined on the permanent refractory 3 on which the side wall portion 21 on the upper end side is not formed.
The wear refractory 4 of the molten steel pan 1 is constructed through the steps shown in FIGS. 5 (A) to 5 (D).

<Modification>
Although the present invention has been described above with reference to specific embodiments, it is not intended that the present invention be limited by these descriptions. From the description of the invention, other embodiments of the invention will be apparent to persons skilled in the art, along with various variations of the disclosed embodiments. Therefore, it is to be understood that the claims encompass these modifications and embodiments that fall within the scope and spirit of the present invention.

  For example, in the above embodiment, the vibration device 72 is provided on the mold 7, but the present invention is not limited to such an example. For example, if the irregular refractory serving as the wall portion 41 is reliably filled between the mold 7 and the permanent refractory 3, the vibration device 72 is not necessarily provided. In addition, as long as the mold 7 can be vibrated, the vibration device 72 may be provided on a portion other than the inner peripheral surface of the mold 7. Further, when the vibration device 72 is provided between the mold 7 and the permanent refractory 3, and when the amorphous refractory is poured between the mold 7 and the permanent refractory 3, the amorphous refractory is poured while vibrating. It may be a configuration.

  Moreover, in the said embodiment, although the laying part 42 of the wear refractory 4 was set as the structure which an upper surface inclined, this invention is not limited to this example. For example, as shown in FIG. 6, in the equipment capable of inclining the molten steel pan 1 itself during casting, the upper surface of the laying portion 42 may be formed horizontally. In FIG. 6, the z axis is a vertical direction orthogonal to the x axis and the y axis. Reference numeral 8 indicates molten steel, and reference numeral 9 indicates slag. Thus, when the molten steel pan 1 itself can be inclined during casting, the inclined portion 411 is formed so that the upper surface of the laying portion 42 is lower than the tuyere 5 in the state during casting. .

  Furthermore, in addition to the above-described embodiment, as shown in FIGS. 7 and 8, at least one recess 412 may be formed on the inner peripheral surface of the end of the wall 41 on the bottom 22 side. For example, in the example shown in FIG. 7, three concave portions 412 are formed in an arc shape on the inner peripheral surface of the wall portion 41 on the side where the inclined portion 411 is not formed. And it becomes the shape where the circumferential direction edge part of the laying part 42 protruded so that the recessed part 412 might be fitted. Such a recess 412 is easily formed by pouring an amorphous refractory in a state shown in FIG. 5B with a foam plastic or the like easily attached to the lower end side of the mold 7. be able to.

  Furthermore, in the said embodiment, although it was set as the structure which the inclination part 411 inclines in one step as shown in FIG. 2, this invention is not limited to this example. For example, as illustrated in FIG. 9, the inclined portion 411 may be configured to be inclined in two steps in a cross-sectional view perpendicular to the height direction. Moreover, the structure which inclines to two or more steps | paragraphs may be sufficient.

Furthermore, in the said embodiment, although the formwork 7 was set as the substantially cylindrical shape, this invention is not limited to this example. The mold 7 may be cylindrical, and if the wall 41 of the ware refractory 4 is formed by pouring an amorphous refractory between the mold 7 and the permanent refractory 3, The shape (for example, solid cylindrical shape) other than embodiment may be sufficient.
Furthermore, in the said embodiment, although the amorphous refractory was used for the laying part 42 of the wear refractory 4, the present invention is not limited to this example. For example, a part of the laying part 42 may be a regular refractory.

<Effect of embodiment>
(1) The mold 7 of the molten steel pan 1 according to one aspect of the present invention is a mold 7 used when lining the ware refractory 4 inside the molten steel pan 1, and the bottom of the molten steel pan 1 (outside An inclined portion of the molten steel pan 1 that falls toward the side wall portion (side wall portion 21 of the outer shell 2) of the molten steel pan 1 in the vicinity of the tuyere 5 of the molten steel pan 1 on the side surface on the lower end side that becomes the bottom portion 22) of the shell 2 The notch part 71 which forms 411 is provided.

  According to the configuration of (1) above, the inclined portion formed at the bottom of the molten steel pan 1 provided for reducing the remaining steel can be formed integrally with the wall portion 41 of the wear refractory 4. For this reason, after constructing the wear refractory 4, compared with the conventional construction method in which the inclined portion 6 is separately provided, the bonding strength between the inclined portion 411 and the wall portion 41 (the conventional inclined portion 6 and the laying portion 42 are Bonding strength) can be improved. Thereby, the inclined portion 411 is less likely to be worn away and the amount of remaining steel can be reduced over a long period of time.

  In addition, since the conventional inclined portion 6 is lined by hand coating, it is difficult to increase the height of the inclined portion 6 or to make the inclination angle steep. However, according to the configuration of (1), the inclined portion 411 is lined while being restrained by the mold 7, so that the inclined portion 411 having a high height and a sharp inclination angle can be formed. For this reason, the residual steel amount reduction effect by the inclination part 6 can be improved. Moreover, since the height of the inclined portion 6 can be kept high even if it is melted and worn out, the amount of remaining steel can be reduced over a long period of time. For example, when the wall portion 41 and the laying portion 42 are formed of a general alumina / spinel refractory material, it is difficult to form the inclined portion 6 with a thickness of 100 mm or more with respect to the laying portion 42a by the conventional method. Met. However, according to the configuration of (1) above, the height of the inclined portion 411 with respect to the laying portion 42 can be set to 100 mm or more (for example, 150 mm).

(2) In the configuration of (1), a vibration device 72 is further provided inside.
According to the configuration of (2) above, since the amorphous refractory is easily filled up to the space on the notch portion 71 side, the inclined portion 411 can be reliably formed.
(3) The construction method of the molten steel pan 1 according to one aspect of the present invention has a cylindrical shape extending in the height direction of the molten steel pan 1 when lining the wear refractory 4 inside the molten steel pan 1. A side wall portion of the molten steel pan 1 (a side wall portion of the outer shell 2), using a mold 7 having a notch portion 71 on the side surface on the lower end side which is the bottom portion of the molten steel pan 1 (the bottom portion 22 of the outer shell 2). 21) lining the wall portion 41 of the wear refractory 4 having the inclined portion 411 falling toward the tuyere 5, and after lining the wall portion 41, the laying portion of the wear refractory 4 inside the wall portion 41 42 is lined.
According to the configuration of (3) above, the same effect as the configuration of (1) can be obtained.

(4) In the configuration of the above (3), when lining the wall 41 of the wear refractory 4, the inner peripheral surface of the end of the wall 41 of the wear refractory 4 on the side of the wall 41 (the bottom 22 of the outer shell 2). The recess 412 is formed.
According to the configuration of the above (4), even when molten steel is inserted between the laying part 42 and the permanent refractory 3, the floating of the laying part 42 from the permanent refractory 3 can be prevented, and the molten steel pan Leakage from steel can be prevented.

(5) A molten steel pan 1 according to one aspect of the present invention includes a bottomed cylindrical outer shell 2, a wear refractory 4 lined inside the outer shell 2, and a wing provided on the bottom 22 of the outer shell 2. The wear refractory 4 includes a wall portion 41 that is lined on the side wall portion 21 of the outer shell 2, and a laying portion 42 that is lined inward of the wall portion 41 in the bottom portion 22 of the outer shell 2. The wall portion 41 is formed integrally with the wall portion 41, and has an inclined portion 411 that falls from the side wall portion 21 toward the tuyere 5 near the tuyere 5.
According to the configuration of (5) above, the same effects as the configurations of (1) and (3) can be obtained.

Examples performed by the present inventors will be described. In the examples, using the construction method of the molten steel ladle 1 according to the above embodiment shown in FIG. 5, the molten steel pan 1 shown in FIGS. 1 and 2 is constructed and used until the life of the refractory is reached. The shape of the part 411 was measured.
In the examples, the constructed molten steel ladle 1 received 135 charges (times) and molten steel, which became the refractory life. When the inclined part 411 after use was measured, there was no peeling and it was confirmed that the original size was maintained even after use. Moreover, also about the amount of remaining steel after casting, it confirmed that the high residual steel amount reduction effect was acquired irrespective of the frequency | count of use. That is, according to the molten steel ladle 1 constructed using the mold 7 and construction method of the molten steel ladle 1 according to the above embodiment, it was confirmed that the amount of remaining steel can be reduced over a long period of time.

DESCRIPTION OF SYMBOLS 1,1a Molten steel pan 2,2a Outer shell 21,21a Side wall part 22,22a Bottom part 3,3a Permanent refractory 4,4a Wear refractory 41,41a Wall part 411 Inclined part 412 Recess 42,42a Laying part 43,43a Slag Line part 5, 5a Tuyere 6 Inclined part 7, 7a Formwork 71 Notch part 72 Vibration device

Claims (5)

A formwork used for lining ware refractories inside a molten steel pan,
It has a cylindrical shape extending in the height direction of the molten steel pan,
The notch part which forms the sloping part of the said molten steel pan which falls toward the said tuyere from the side wall part of the said molten steel pan in the vicinity of the tuyere of the said molten steel pan on the side surface of the lower end side used as the bottom part side of the said molten steel pan A form of a molten steel pan characterized by comprising:   The mold for a molten steel pan according to claim 1, further comprising a vibration device inside. When lining ware refractories inside the molten steel pan,
From the side wall of the molten steel pan, using a mold having a cylindrical shape extending in the height direction of the molten steel pan, and having a notch on the side surface on the lower end side that is the bottom side of the molten steel pan. Lining the wall portion of the wear refractory having an inclined portion that falls toward the tuyere,
A method for constructing a molten steel pan, characterized in that after lining the wall portion, a laying portion of the wear refractory is lined inside the wall portion.   The method for constructing a molten steel pan according to claim 3, wherein when the wall portion is lined, a concave portion is formed on an inner peripheral surface of the end portion on the bottom side of the wall portion. A bottomed cylindrical outer shell,
A wear refractory lined inside the outer shell;
A tuyere provided at the bottom of the outer shell,
The wear refractory has a wall portion lined on a side wall portion of the outer shell, and a floor portion lined inward of the wall portion at the bottom portion of the outer shell,
The said wall part is integrally formed with this wall part, and has the inclination part which falls toward the said tuyere from the said side wall part in the vicinity of the said tuyere, The molten steel pan characterized by the above-mentioned.

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