Tundish for horizontal continuous casting

Abstract

 A tundish (10) for a horizontal continuous casting having a feed nozzle (18) being fixed to a first side wall (12a) of the tundish (10) and supplying molten metal (14) to a horizontal mold (16), comprising: a discharging nozzle (26) fixed to a confronting position at a lower portion of a second side wall (12b) of said tundish (10) on the opposite side of said first side wall (12a) and having a discharging bore (28) flaring outwardly out of said tundish (10), for discharging a part of the molten metal (14) remaining in said tundish (10); a plug (30) mating with said discharging bore (28) and being releasedly inserted from the outside of said tundish (10) into said discharging bore (28), so as to be able to be fitted to and taken out of the discharging bore (28); and a runner pipe (22) having an opening (24) through which molten metal (14) flows in said runner (22) from said tundish (10) above said runner pipe (22) and connecting said feed nozzle (18) to said discharging nozzle (26).

Description

[0001] The present invention relates to a tundish for a horizontal continuous casting, and more particularly, to a discharging mechanism for molten metal remaining in a tundish at the end of the horizontal continuous casting.

[0002] A continuous horizontal casting apparatus is provided with a mold mounted horizontally at a lower portion of a side wall of a tundish. The mold is adjoining to the tundish through a feed nozzle. A billet is pulled out through the mold in the horizontal direction and thus the billet is continuously cast. At the end of the horizontal continuous casting,molten metal remaining in the tundish is discharged through a discharging bore provided at the bottom of the tundish. As a prior art of the discharging mechanism, US Patent No.4,298,147 is mentioned.

[0003] In this prior art, a discharging mechanism for molten metal and slag is disclosed, which comprises :
a tundish having at least one feed nozzle ;
a discharging nozzle having a discharging bore flaring outwardly and downwardly, for discharging molten metal and slag remaining in said tundish, said discharging nozzle being fixed to a bottom wall of said tundish substantially in the center of said tundish ;
a plug mating with said discharging bore and being releasedly inserted from the outside of said bottom wall into said discharging bore, so as to be able to be fitted to and taken out of said discharging bore and ;
a plug fitting fixed to the lower end of said plug ; and
a engaging means, connected to said plug fitting, for selectively inserting said plug into said discharging bore, holding said plug in said discharging bore and withdrawing said plug from said discharging bore.

[0004] In this prior art, however, molten metal flows outwardly in the direction of the feed nozzle, a temperature of a side wall confronting to another side wall having the feed nozzle fixed thereto and a bottom wall portion near the former side wall is lowered, and the molten metal solidifies and adheres to the former side wall and the bottom wall. Therefore, this method have been disadvantageous in that the molten metal does not flow out even if the plug is pulled out, or that the plug is hard to pull out because of being torn off.

[0005] It is an object of the present invention to provide a constitution of a tundish for a horizontal continuous casting capable of easily discharging molten metal remaining in the tundish.

[0006] In accordance with the present invention, a tundish for a horizontal continuous casting comprising :
a feed nozzle being fixed to a first side wall of a tundish and supplying molten metal to a horizontal mold ;
a discharging nozzle fixed to a confronting position at a lower portion of a second side wall of said tundish on the opposite side of said first side wall and having a discharging bore flaring outwardly out of said tundish, for discharging a part of the molten metal remaining in said tundish ;
a plug mating with said discharging bore and being releasedly inserted from the outside of said tundish into said discharging bore, so as to be able to be fitted to and taken out of the discharging bore; and
a runner pipe having an opening through which molten metal flows in said runner pipe from said tundish above said runner pipe and connecting said feed nozzle to said discharging nozzle.

[0007] Other features and advantages of the present invention will be apparent from the detailed description to follow, taken in conjunction with the accompanying drawings wherein:

Fig.1 is a cross sectional view illustrating a tundish for a horizontal continuous casting of the present invention ;

Fig.2 is a vertical section view of the tundish for the horizontal continuous casting, taken on line I-I′ of Fig.1.; and

Fig.3 is a plan view of the tundish for the horizontal continuous casting, taken on line II-II′ of Fig. 1.

[0008] Referring specifically to Figs 1, 2 and 3 of the drawings, the present invention will be now described. Fig.1 illustrates a cross section view of a tundish for a horizontal continuous casting of the present invention. Fig.2 illustrates a vertical section view of the tundish for the horizontal continuous casting, taken on line I-I′ of Fig.1. Fig. 3 also illustrates a plan view of the tundish for a horizontal continuous casting, taken on lin II-II′ of Fig. 1.

[0009] Feed nozzle 18 is fixed at a lower portion of a first side wall 12a of tundish 10, supplying molten metal 14 to a horizontal mold 16. Discharging nozzle 26 is fixed to a confronting position at a lower portion of a second side wall 12b of the tundish on the opposite side of the first side wall, and is used for discharging a part of the molten metal remaining in tundish 10. Discharging nozzle 26 has discharging bore 28 which flares outwardly through the second side wall. Plug 30 mating with the discharging bore is inserted into discharging bore 28 from the outside of tundish 10 so releasedly as to be able to be fitted to or taken out of the discharging bore. Runner pipe 22 is arranged at bottom wall 20 of tundish 10, having opening 24 through which molten metal 14 flows in runner pipe 22 from the tundish above the runner pipe and connecting feed nozzle 18 to discharging nozzle 26.

[0010] Runner pipe 22 is made from refractory. The refractory is preferably selected as any one from the group consisting of zircon, magnesia, alumina-graphite and magnesia-graphite which have property of corrosion resistance and spalling resistance against molten metal 14.

[0011] It is preferable that diameter D₁ of a circle corresponding to a section area of the runner pipe is 0.5 to 2.0 of diameter D of a circle corresponding to a section area of mold 16, provided, however, that D₁ is preferably 80 mm or more, where a diameter of circle corresponding to a section area equals to a diameter when the section shape of the runner pipe is a circle and it equals to a length computed by the formula of ˝(2/√π)x(a length of a side)˝ when the section shape of the runner pipe is a square.

[0012] Opening 24 of runner pipe 22 is preferably arranged closely by discharging nozzle 26. A distance from discharging nozzle 26 to the center of opening 24 is preferably determined to be diameter D₁ of runner pipe 22 or less.

[0013] Diameter D₂ of a circle corresponding to a section area of opening 24 is preferably 0.7 to 1.2 of diameter D₁ of a circle corresponding to a section area of runner pipe 22,provided,however, the minimum of the diameter D₂ is preferably 80 mm or more.

[0014] Plug 30 mating with discharging bore 28 is made from refractory. The refractory is preferably selected an any one from the group consisting of zircon,magnesia, alumina-graphite and magnesia-graphite which have property of corrosion resistance and spalling resistance against molten metal 14.

[0015] Next, an actual operation of a tundish of the present invention will be described. An inside of tundish 10 is preheated by fuel to 1200 to 1300 ° C before molten metal 14 is charged. After the preheting of the tundish, molten metal 14 is poured onto bottom wall 20 of tundish 10 from a ladle ( not shown ). The molten metal introduced into the tundish flows into runner pipe 22 through opening 24 and the runner pipe is full of molten metal 14. When molten metal 14 increases to a certain level of the inside of the tundish,a drawer ( not shown ) set in mold 16 begins to work and a billet to be made from the molten metal is drawn out. Molten metal 14 in runner pipe 22 moves into mold 16 through feed nozzle 18. Since molten metal 14 in tundish 10 flows closely by discharging bore 28, second side wall 12b and a portion of bottom wall 20 neighboring with a lower portion of the second side wall are kept at a high temperature and there is no fear that molten metal 14 solidifies and adheres to walls of the tundish. Consequently, when molten metal 14 becomes as high as an upper side level of runner pipe 22 at the end of the casting operation, molten metal 14 flows out promptly through discharging bore 28 upon drawing out plug 30 inserted in discharging nozzle 26. Comparison of ratio of success in discharging molten metal 14 of the present invention with that of a prior art tundish is shown in Table 1. When a tundish of the present invention was used, molten metal 14 flowed out successfully all out of 25 times of the discharging upon drawing out plug 30. The ratio of success was 100 %. But, when a prior art tundish was used, the molten metal failed to be discharged at 8 of 37 times of the operation upon drawing out plug 30. Thus, the present invention improves greatly the success ratio of discharging molten metal at the end of the horizontal continuous casting.

Table 1

	N	SUCCESS	FAILURE
PRESENT INVENTION	25	25	0
PRIOR ART	37	29	8

Claims

1. A tundish for a horizontal continuous casting having a feed nozzle (18) being fixed to a first side wall (12a) of a tundish and supplying molten metal (14) a horizontal mold (16), characterized by comprising:
a discharging nozzle (26) fixed to a confronting position at a lower portion of a second side wall (12b) of said tundish (10) on the opposite side of said first side wall (12a) and having a discharging bore (28) flaring outwardly out of said tundish (10), for discharging a part of the molten metal (14) remaining in said tundish (10);
a plug (30) mating with said discharging bore (28) and being releasedly inserted from the outside of said tundish (10) into said discharging bore (28), so as to be able to be fitted to and taken out of the discharging bore (28); and
a runner pipe (22) having an opening (24) through which molten metal (14) flows in said runner pipe (22) from said tundish (10) above said runner pipe (22) and connecting said feed nozzle (18) to said discharging nozzle (26).

2. The tundish of claim 1, characterized in that said opening (24) of said runner pipe (22) includes an opening (24) being arranged closely by said discharging bore (28).

3. The tundish of claim 1, characterised in that said opening (24) of said runner pipe (22) includes an opening (24) having a diameter D₂ which is 0.7 to 1.2 of a diameter D₁ and the diameter D₂ is 80 mm or more, where the diameter D₂ is a diameter of a circle corresponding to a section area of the opening (24) and the diameter D₁ is a diameter of a circle corresponding to a section area of the runner pipe (22).

4. The tundish of claim 1, characterised in that said runner pipe (22) includes a runner pipe (22) having a diameter D₁ which is 0.5 to 2.0 of a diameter D and the diameter D₁ is 80 mm or more, where the diameter D₁ is a diameter of a circle corresponding to a section area of the runner pipe (22) and the diameter D is a diameter of a circle corresponding to a section area of the mold (16).

5. The tundish of claim 1, characterized in that said runner (22) includes being made from any one selected from the group consisting of zircon, magnesia, alumina-graphite and magnesia-graphite.

6. The tundish of claim 1, characterized in that said plug (30) includes being made from any one selected from the group consisting of zircon, magnesia, alumina-graphite and magnesia-graphite.

Drawing