JPH0323044A - Method and apparatus for pouring molten steel into tundish in continuous casting - Google Patents

Abstract

PURPOSE:To enable pouring of the whole of molten steel from a ladle by arranging a surrounding weir opened at upper and lower ends in molten steel pouring part in a tundish and surrounding the outside thereof with an outer weir to form a molten steel storing part. CONSTITUTION:The surrounding weir 22 opened upper and lower ends is arranged in the molten steel pouring part 20 in the tundish body 18 from the ladle in the width direction of tundish body 18 and both ends thereof are fixed to the inner walls 18A. The outer weir 24 is arranged at the outside of surrounding weir 22 and the lower ends thereof are fixed to the bottom part wall 18B, and the molten steel pouring part 20 is formed with the surrounding weir 22 and the outer weir 24. The whole of molten steel from the ladle is poured into the surrounding weir 22 arranged in the molten metal pouring part 20. The poured molten steel and slag are allowed to flow to the outer weir 24 from the opening part at the lower part of surrounding weir 22 and further, by making to overflow the outer weir 24, this is stored in the bottom part in tundish body 18. Then, the slag is shut in the surrounding weir 22 and does not flow out to the outside. Therefore, only the molten steel accompanying no slag can be continuously cast in a mold 14.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method and device for pouring molten steel into a tundish in continuous casting, and particularly relates to a method and an apparatus for pouring molten steel into a tundish in continuous casting. An external weir is installed with the lower end fixed to the bottom of the tundish, and even if the entire amount of molten steel in the ladle is poured into the enclosing weir, the siphon type molten steel storage part prevents slag from being mixed in when pouring molten steel into the mold. The molten steel injection method and device are effectively used in the field of continuous steel casting. [Prior art] The conventional technology of continuous casting will be explained with reference to Fig. 4. Molten steel 2 melted in a converter etc. is stored in a ladle 4, but at this time, the entire amount of melted steel is tapped into the ladle 4, so the slag 6
It is difficult to avoid contamination of the slag 6 in the ladle 4, and the slag 6 in the ladle 4 is necessary at a minimum from the standpoint of preventing oxidation of the molten s2. However, in the continuous casting tundish 8, the molten steel 2 in the ladle 4 that is being conveyed is received through the sliding nozzle 10 and long nozzle 12 provided at the bottom of the ladle, but at this time, the slag 6 should not be mixed in as much as possible. Therefore, pouring is stopped with some molten copper 2 remaining in the reserve 4. For example, when collecting 250 tons of coins, the injection into Tanditsh 8 is usually stopped when about 5 tons remain. However, since molten steel is poured into the tundish 8 many times, it is unavoidable to some extent that slag gets mixed in, and the remaining steel left in the ladle 4 has to be discarded as scrap along with the slag 6. This is a huge problem in terms of cost. On the other hand, when pouring from the tundish 8 into the mold 14, casting is performed through the immersion nozzle 16 as shown in FIG. Therefore, in this case as well, Wjll2 from the next ladle 4 is accepted when there is still remaining steel in the tundish 8. There is no problem in the case of continuous casting of the same steel type, but in the case of continuous continuous casting of different steel types (hereinafter referred to as continuous casting), the previous ′! In the situation where the i-steel is in Tanditshu 8, we have no choice but to inject two different types of molten steel for the next time, so a mixed area of the previous steel type and the next different type will occur, and this part will have to be scrapped. However, in this case as well, cost is an important issue. As a method of preventing the slag 6 from entering the tundish 8 from the ladle 4, an inert gas such as Ar is continuously blown from the long nozzle 12 or the sliding nozzle 10 at the end of injection, and the slag is Although methods have been proposed to prevent the mixing of slag 6, there is a period at the end of injection when slag 6 and melt m2 mix and flow out, and the flow of slag 6 during this period cannot be prevented. Note that if the molten steel 2 enters the recess of the sliding nozzle 10 and solidifies, it will not operate, so first fill it with sand, but when the ladle 4 is opened, the sand cannot be prevented from flowing out, and the ladle 4
Due to cracking and melting of the refractory bricks, the flow rate of inert gas,
This method is also not a reliable countermeasure because the pressure changes cause fluctuations and the determination of slag cutout is unstable. As described above, an effective measure to prevent the slag 6 from entering the tundish 8 from the molten steel 4 in continuous casting has not yet been found. Instead of pouring the entire amount, as mentioned above, in a 250-ton ladle, approximately 5 tons of molten steel remains and we have no choice but to dispose of this. [Problems to be Solved by the Invention] The purpose of the present invention is to overcome the conventional technique of not injecting the entire amount of molten steel in the ladle and leaving a small amount of molten steel in order to avoid mixing of slag when pouring molten steel from the ladle into the tundish. An object of the present invention is to provide a method and device for pouring molten steel into a tundish in continuous casting, which solves the above problems and can inject the entire amount of molten steel from a ladle into a tundish. [Means for Solving the Problems] The gist of the method for injecting molten metal into tanditshuha according to the present invention is as follows. (1) A surrounding weir with open upper and lower ends is installed at the molten steel injection part from the ladle of the tanditshu,
Continuous casting characterized in that the outside of the surrounding weir is surrounded by an outer weir whose lower end is fixed to the bottom of the tundish to form a molten steel reservoir, and the entire amount of molten steel in the ladle is injected into the surrounding weir. Method of pouring molten steel into tanditshu. (2)
An enclosing weir with open upper and lower ends is provided from the ladle of the tundish to the molten steel injection part, and the outside of the enclosing weir is surrounded by an outer weir whose lower end is fixed to the bottom of the tundish, forming an enclosing storage area. Continuous casting characterized in that at the time when or immediately before the injected molten steel flows out to the mold side through the tundish nozzle, the next receiving injection of the molten steel of different mesh type is started to perform continuous continuous casting of different steel types. This is a method of injecting molten steel into the tanditshu. The gist of the apparatus for implementing the molten steel injection method according to the present invention is as follows. (3) It is formed by a surrounding weir with open upper and lower ends provided at the molten steel injection part from the ladle of the tundish, and an outer weir provided outside the surrounding weir and having a lower end fixed to the bottom of the tundish. An apparatus for injecting molten steel into a tundish in continuous casting, characterized by having a molten steel storage section. The enclosing weir may be fixed in the width direction on the longitudinal inner wall of the tundish, and may be made of a cylindrical or polygonal cylindrical fireproof member, and supported on the sealing lid of the tundish so that it can rise and fall freely. It may be one that has been Embodiments of the present invention will be described with reference to the attached drawings. First, a device for injecting molten steel into a tundish according to the present invention is shown in Fig. 1 (
This is explained by A) and (B). Tanditshu body 18
The tundish main body 1 is inserted into the molten steel injection part 20 from the ladle 4.
An enclosing weir 22 made of refractory material with open upper and lower ends is provided in the width direction of the tundish body 18, and both ends thereof are fixed to the inner wall 18A of the tundish main body 18 in the longitudinal direction. An outer weir 24 is provided outside the enclosing weir 22 in parallel with the enclosing weir 22, and its lower end is fixed to the bottom ul8B of the tundish main body 18, and the enclosing weir 22 and the outer weir 24 form a molten steel storage section 20. are doing. Another aspect of the device for injecting mei into tandishes according to the present invention will be explained with reference to FIGS. 2(A) and 2(B). In this case, the enclosing weir 22A is as shown in Fig. 2 (A). As shown in the cross-sectional shapes shown in (B) and FIGS. 3(A) and (B), the seal lid 26 is made of a cylindrical or polygonal cylindrical fireproof member and is provided on the seal lid 26 provided on the upper part of the tundish main body 18. It is supported by an annular support 28 and can be raised and lowered via a steering gear [30]. In this case as well, the outer weir 24 has the same structure as that described in FIG. [Operation] The operation of the present invention will be explained using a jFsl diagram. In the present invention, when pouring the molten steel 2 from the ladle 4 into the tundish 8, unlike the conventional method, the entire amount of the molten steel 2 is not poured into the tundish 8 at the end of pouring when there is a risk of the slag 6 flowing out, but a portion is left behind. The entire amount is injected into the surrounding weir 22 provided in the molten steel injection section 20. The molten steel 2 and slag 6 injected into the enclosure weir 22 flow from the open part at the bottom of the enclosure weir 22 to the outer weir 24, overflow the outer weir 24, and are stored at the bottom of the tundish body. In this case, H:: Slag head inside the molten steel injection section 20 HM: Metal head inside the I steel injection section 20 HO&I: Metal head inside the outer weir 24 ρ●: Slag specific gravity p&I: Molten steel specific gravity, then the molten steel of #l44 2. When the entire amount of slag 6 is injected, the static balance between the melt 1l2 and slag 6 in the surrounding weir 22 and the outer weir 24 is maintained as shown in equation (1), and the slag 6
is confined in the enclosure weir 22 and does not flow outside. HoM*ρm=Hs. pm+Hm”/)m”・・”(
1) Thus, when the molten steel 2 is sequentially poured into the tundish 8 from the ladle 4, even if the slag 6 gets mixed in, it is trapped within the enclosure weir 22 and does not flow out to the outside, and only the so-called molten steel 2 overflows the outer weir. Since it is stored at the bottom of the tundish 8, only the molten steel 2 without the slag 6 can be continuously cast into the mold 14 by opening the immersion nozzle 16 at the bottom of the tundish 8. In addition, FIG. 1 shows a tundish 8 for two strands of strands A and B.
According to the present invention shown in FIG. 1, even if the ladle 4 is sequentially changed and the entire amount of molten steel 2 and slag 6 is poured into the tundish 8, as long as the balance of equation (1) is maintained, The slag 6 is confined in the enclosure weir 22 and does not flow out. When the slag 6 accommodated in the B weir 22 reaches its limit, the tundish 8 is carried by the tundish force to the molten steel and slag discharge bit, and the slag 6 is discharged. At this time, a small amount of molten steel 2 stored in the outer weir 24 is also discarded, but compared to the conventional method, the amount is extremely small and the outer weir 2
The molten steel 2 overflowing from the slag 4 and stored at the bottom of the tundish 8 does not contain any slag 6, and can be injected into the mold 14 through the immersion nozzle 16. Next, see Figure 2 (A). The operation of the other embodiment of the present invention shown in (B) will be explained. In this case, the enclosing weir 22A is supported by a pillar 28 erected on the seal [26], and is movable up and down by the parking device [30], so that the enclosing weir 22A of the fixed type shown in FIG.
Compared to 2, it has the following effects. (b) To prevent the slag 6 stored in the enclosure weir 22A from flowing out into the outer weir 24, the depth of immersion of the lower end of the enclosure weir 22A into the melt s2 is changed by raising and lowering the enclosure weir 22A. be able to. (Explanation) The immersion position can be changed by raising and lowering the enclosure weir 22A in response to partial erosion of the enclosure weir 22A. In addition to the above-mentioned functions and effects, the original function is the same as that of the fixed enclosing weir 22 shown in Fig. 1. Next, we will explain the effects of continuous casting of different types. When using the apparatus for injecting molten steel 2 into the tundish 8 according to the present invention shown in FIGS. 1 and 2, the slag 6 is confined within the surrounding weirs 22 and 22A, All of the molten steel 2 of #112 that overflowed the outer weir 24 and was stored at the bottom of the tundish 8 can be injected into the mold 14, so the remaining steel is only that stored in the outer weir 24. Therefore, when successive casting of different steel types is carried out at this stage, even if the entire amount of molten steel 2A of different steel types is injected into the enclosing weir 22.22A together with slag 6A, the slag 6
A is mixed with the previous slag 6 and confined in the surrounding weirs 22 and 22A, and the molten steel 2A of different steel types and the previous molten steel 2 mix only with the molten steel 2 stored in the outer weir 24, so that Compared to the amount of molten steel stored in the entire bottom of Tundish 8, only a very small amount of molten steel is required to be mixed, and the mixing area of slabs that must be discarded can be greatly reduced. Therefore, the previous molten steel 2 remains at the bottom of the tundish 8.
If the next two molten steels of different steel types are injected into the enclosing weirs 22 and 22A at the time of completion of casting the entire amount into the mold 14 or just before that, only a very small mixing area will be generated, and the molten steel of different steel types will be poured into the mold 14. Casting can be carried out. [Effects of the Invention] fI for tanditshu according to the present invention! I-steel injection equipment is equipped with a surrounding weir whose upper and lower ends are open at the part where molten steel is injected from the ladle of the tundish, and an outer weir with the lower end fixed to the bottom of the tundish outside of the weir. By using a method in which a molten steel injection part was formed by using a method in which the entire amount of molten steel in the ladle was injected into the molten steel injection part, the following effects were achieved. (b) Even if the entire amount of molten steel in the ladle is injected into the enclosure weir of the tandish along with slag, the slag will be trapped within the enclosure weir and will not flow toward the outer weir, so there is no outer weir at the bottom of the tandish. When only the overflowing molten steel that does not contain slag is stored and cast into a mold through a submerged nozzle, only molten steel that does not contain slag can be cast, which improves the quality of the manufactured slab. (Note) Since the entire amount of molten steel in the ladle can be poured into the tundish, the amount of waste molten steel is significantly reduced and costs are reduced compared to the conventional method where some molten steel is left in the ladle to avoid contamination with slag. is now possible. (c) When continuously casting different steel types, the amount of previous molten steel #lII remaining in the tundish is only the molten steel in the outer weir, so the amount of mixed molten steel is significantly reduced compared to the conventional method, so the waste mixing The amount of cast slabs in the area was significantly reduced. (2) The enclosing weir can be fixed in the width direction to the longitudinal inner wall of the tundish, and the outer weir can be fixed to the bottom wall of the tundish, and only the enclosing weir can be supported on the seal lid so that it can move up and down. Carrying capacity can be increased. (e) Since it is no longer necessary to manage the amount of remaining steel in ladles, tundishes, etc. during continuous casting operations, operational management has become more important than before.

[Brief explanation of the drawing]

Figure 1 (A). (B) is a sectional view showing the configuration of a device for injecting molten steel into a tundish according to the present invention, and (A)
(B) is a front view showing a two-strand type device of the present invention;
is a plan view, Figure 2 (A). (B) is a sectional view showing another embodiment of the molten steel injection device according to the present invention, in which (A) is a front view and (B) is a plan view. Figure 3 (A), CB) is Figure 2C
B) shows a cross-sectional shape other than the cylindrical enclosing weir,
(A) is a sectional view of a rectangular cylindrical shape, (B) is a sectional view of a hexagonal cylindrical shape, and FIG. 4 is a sectional view showing a conventional continuous casting apparatus. 2... Molten steel 4... Ladle 6... Slag 8... Tundish 10... Sliding nozzle 12... Long nozzle 14... Mold 15...
Slab 16... Immersion nozzle (Tundish nozzle) 8...
・Tandish body 8A...Tandish inner wall 8B...Bottom * 20... Molten steel injection part 2,
22A... Enclosure weir 24... Outer weir 6... Seal lid 28... Support column O... Adjustment device

Claims (5)

[Claims] (1) A surrounding weir with open upper and lower ends is provided in the molten steel injection portion from the ladle of the tundish, and a molten steel storage section is formed by enclosing the outside of the surrounding weir with an outer weir whose lower end is fixed to the bottom of the tundish. A method for pouring molten steel into a tundish in continuous casting, characterized in that the entire amount of molten steel in the ladle is injected into the surrounding weir. (2) providing a surrounding weir with open upper and lower ends in the molten steel injection part from the ladle of the tundish, and forming a molten steel storage section by enclosing the outside of the surrounding weir with an outer weir whose lower end is fixed to the bottom of the tundish; Continuous casting characterized in that the next injection of molten steel of a different steel type is started at the time when or immediately before the molten steel injected previously flows out to the mold side through a tandate nozzle, and continuous continuous casting of different steel types is performed. A method for injecting molten steel into a tandate. (3) It is formed by a surrounding weir with open upper and lower ends provided in the molten steel injection part from the ladle of the tundish, and an outer weir provided outside of the surrounding weir and having a lower end fixed to the bottom of the tundish. 1. An apparatus for injecting molten steel into a tundish in continuous casting, characterized by having a molten steel storage section. (4) The device for injecting molten steel into a tundish in continuous casting according to claim 3, wherein the enclosing weir is fixed in the width direction to the longitudinal inner wall of the tundish. (5) The device for injecting molten steel into a tundish in continuous casting according to claim 3, wherein the enclosing weir is made of a cylindrical or polygonal cylindrical fireproof member and is supported by the seal lid of the tundish so that it can be raised and lowered.