US3599708A

US3599708A - Bottom pouring apparatus for steel ingots

Info

Publication number: US3599708A
Application number: US749173A
Authority: US
Inventors: Kazuro Suzuki; Mitsuo Oda; Takao Suzuki
Original assignee: Sumitomo Metal Industries Ltd
Current assignee: Nippon Steel Corp
Priority date: 1967-08-04
Filing date: 1968-07-31
Publication date: 1971-08-17
Anticipated expiration: 1988-08-17
Also published as: DE1758761A1; DE1758761C3; DE6600169U; DE1758761B2; GB1231867A

Abstract

Making ingots in steel production, wherein casting molds filled with molten metal are moved on a board the surface of which blocks molten metal for steel ingots, but permits the flow of the metal, said molten metal runner routes being reusable.

Description

United States Patent [72] Inventors Kazuro Suzuki lbargagi-shi;

Mitsuo Oda, Nishinomiya-shi; Takao 249/109 X 249/109 X 164/156 164/155 X I 164/66 X 3,296,665 1/1967 Fenzan 3,353,586 11/1967 Dressel... 3,443,629 5/1969 Ebeling 3,467,167 9/1969 Mahin..............

Suzuki, Nishinomiya-shi, all of, Japan [21] Appl. No. 749,173 [22] Filed July 31, 1968 [45] Patented Aug. 17, 1971 [73] Assignee SumitomoMetal Industries, Ltd.

Osaka, Japa FOREIGN PATENTS 1 Priority l/l873 GreatBritain......... 1

Mr a e m .m m mmmA Mr. .m mu In fl w mm DWI p6 AJG d 934Jm 66 n. 999 a H fl m 9 0 mm X x wE y W 2 am .m0 9 nu PA Aug. 4, 1967 Japan 42/511025 ABSTRACT: Making ingots in steel production, wherein cast- 164/332, 249/109 [51] Int. B22d4l/08 ing molds filled with molten metal are moved on a board the [50] Field of 249/109; surface of which blocks molten metal for steel ingots, but per- 164/154156, 337, 66, 119, 136, 133, 322; mits the flow of the metal, said molten metal runner routes 141/198, 283, 374 being reusable.

PATENTED AUG! 71971 sum 3 [IF 4 IV I v/jlu s I K mm M T m kw VO m kum w mt A MT mu BOTTOM POURING APPARATUS FOR STEEL INGOTS BACKGROUND OF THE INVENTION- The present invention relates'to an economical bottom casting method and the construction of an apparatus for making ingots in steel production.

The bottom casting method for simultaneously making a plurality of steel ingots by means of a guide tube comprises building a'series of molten metal runner routes branching from a guide tube with each route leading to a steel ingot mold. With this method the casting speed is slower than with the top casting method but the molten metal rises up inside the mold smoothly without splashing, so a fine texture is obtained making this method suitable for the mass production of steel ingots. It is a well known fact that, in the bottom casting method, the principal operation is to form the molten metal runner routes, which constitute the main portion of the apparatus.

In the conventional bottom casting method, however, the routes reaching the steel ingot molds 9 positioned on the small board are formed by bonding with mortar miscellaneous kinds refractories such as sprues 1, guide tube bricks 2, center brick 3, runner bricks 4 radially branching from center brick 3 and reaching the sliding board, and board bricks 6 etc. and also connecting them on the board 7. Therefore, so-called mold setting and breaking operations are required. That is, it is necessary to assemble a series of ingot making apparatuses by constructing molten metal guide routes with a plurality of bricks miscellaneous shapes and to break up or separate these runner routes after casting and taking out ingots and steel scraps in the runner routes. These operations require the use of many workers under very hot and severe conditions, and, accordingly, production is lowered. Moreover, refractory consumption is very high, because the refractories in the molten metal guide routes, which make up most of the refractories used in the ingot making apparatus, can be used for only one single casting operation, and then must be scrapped.

Therefore, it is desirable to have reusable molten metal runner routes so the construction and breaking up of runner routes for each charge become unnecessary. It is evident that with reusable runner routes the steel production process would be simplified, the productivity increased and also the consumption of refractory would be remarkably reduced. The purpose of this invention is to realize the above-mentioned advantages by reusing the runner routes.

This invention is based on the inventors observation that it was i the existence of excess molten metal, deposited and solidified in the runner routes after casting, blocking and occupying said runner routes which made it impossible to reuse the molten metal runner routes and the inventors discovery that said excess metal could be removed, without damaging the routes, if in molten condition. This invention was completed after experiments proved that these refractories in the runner routes, even normal quality refractories like for example, chamotte bricks were damaged surprisingly little if the time of contact with molten metal was short.

SUMMARY OF THE INVENTION This invention is characterized in that steel ingots are obtained by pouring molten metal in the casting molds then blocking the molten metal runner bores in the bottom of the molds with the refractories, care being taken to insure that any excess of molten other than that desired in the ingots is thoroughly discharged out of the apparatus prior to its solidification and does not remain in the molten metal runner routes.

The first object of this invention is, therefore, to provide a method for casting steel ingots which makes it possible to use the molten metal runner routes repeatedly and to decrease remarkably the work of mold setting and breaking.

An other object of this invention is to construct the molten metal runner routes so as to be reusable by means of the improved bottom casting method as described above and thereby to decrease the refractory consumption and to decrease remarkably the quantity of refractories required.

Another object of this invention is to collect all the excess molten metal, other than that to be made into steel ingots, in the molten state without degrading the quality and return said excess metal to the furnace to improve the ingot yield.

The other objects, features and advantages of this invention will be made evident by the description and drawings hereunder.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cut front elevation showing the ingot making apparatus of the conventional bottom casting method. FIG. 2, 3, 4, 5, 6, 7, 8, and 9 show the construction of the ingot making apparatus according to the bottom casting method of this invention. FIG. 2 is a partially cut front elevation of the apparatus. FIG. 3 is a side view of the apparatus taken from III-line of FIG. 2. FIG. 4 is a bottom view of the sliding board. FIG. 5 is a partially cut front elevation of the apparatus showing how to block molten metal. FIG. 6 is a perspective view of the other shape of refractory of the sliding board. FIG. 7 is the plan of the sliding board with a different shape. FIG. 8 is a side view showing the cross section taken along VIII-VIiI line of FIG. 7. FIG. 9 is a drawing illustrating the bottom casting apparatus and the automatic operation related thereto of this invention.

DETAILED DESCRIPTION THE PREFERRED EMBODIMENTS The preferred embodiments of the method and apparatus of this invention are described below. It is to be understood that this invention is not limited only to these embodiments.

Now, referring to the attached drawings, an embodiment of the bottom casting method, according to the present invention and the ingot making apparatus thereof will be described. In FIG. 2, 8 is a guide tube, 9 is a steel ingot mold and 10 is a sliding board. The position of these members on the board 7 and also the disposition of the molten metal runner routes, (the conventional small board 10 according to FIG. 1) are similar to those of the conventional method, but the sliding board, runner routes and molten metal discharge section differ in construction from the conventional ones. Namely, in FIGS. 2, 3, 4 and 5 an elliptical or circular sliding board refractory is provided in the center of sliding board 10 with sliding board bore 11 forming the vertical molten metal runner route reaching steel ingot mold 9. Said sliding board bore 11 does not go beyond the center pint on the longer axis on one side of the sliding board refractory 12 of the bottom surface of which is in the same horizontal plane as the bottom surface 13 of sliding board 10. The molten metal runner route in the runner section passing from the sliding board bore 11 to the guide tube 8 is constructed to back up the runner refractory l4, and slopes evenly in the direction of the guide tube. The insulating refractory 16 of the board 7, and also the top surface of the runner refractory 14 forming the runner bore 17, which serves as the molten metal runner route connected to the sliding board 11, and the top surface of said back up refractory 16 are all in the same horizontal plane as the top surface of the board 7. Also in the guide tube 8 the molten metal route is constructed in the same way as mentioned above, with the guide tube refractory l8 and the insulating refractory I6 backing up said surface 18. I

The molten metal discharge section is provided just under the guide tube 8 from which branches a plurality of runner routes. It is comprised of the discharge port 17 and the nozzle brick 20 connected thereto, and the stopper head brick 22 for opening and closing the nozzle 21 by engaging with the lower end of the nozzle brick 20, and the opening and closing device of molten metal discharging port 23 holding the stopper head brick 22, said nozzle brick 20 and stopper head brick 22 both being replaceably secured to the bottom portion of the board 7 and the opening and closing device of discharging port 23.

The same bricks as are commonlyused for the steel making ladle are generally used for the nozzle brick 20 and the stopper head brick 22. The back up refractory 16 is preferably formed by building up or pouring in the refractorymaterial which is adiabatic and withstands the compressive stress. However, the molten metal runner routes may be formed by first assembling series of molten metal runner routes from the guide tube sprue section to the runner bore 17 in the guide tube case or in the board groove by means of resin pipes-or vinyl pipes, then building up or pouring in unshaped refractory material, and finally melting away or burning said pipes after hardening of said material.

Then, to realize the bottom casting method for ingot making according to this invention the mold setting work will be completed by providing the sliding board 10 on the board 7 uniting the runner bore 17 and the sliding board bore 11 by means of the pusher 24, then placing the steel ingot molds in position and at the same time attaching the nozzle brick 20 and stopper head brick 22 and closing the nozzle 21 by means of the discharging port device 23. After completion of casting operation the sliding board 10 loaded with ingot molds 9 filled with molten metal is slide along on the board 7 a distance not less than the diameter of the bore 11 by means of a proper pusher means such as oil pressure, etc. prior to solidifying of molten metal, and remove the lever 25'of the discharging port device in the direction of the arrow to open the nozzle 21 through which all the molten metal filled in the runner routes other than inside of the steel ingot molds 9 is discharged into the molten metal pan (not shown in the drawing) and then collected. I

FIG. shows sliding board 10 after sliding along the board 7 after casting. The molten metal is divided into molten metal a inside the ingot mold and molten metal b inside the runner route on the contacting surface of the sliding board bore 11 and the runner bore 17 by means of the bottom surface 13 of the sliding board refractory 12, said molten metal a and b being retained with the refractories l2 and 16 dividing and blocking them. The molten metal from the upper portion in the runner bore 17 is thermally insulated by the bottom surface 13 of the sliding board refractory as a result of the shifting of the bore 17 to the position shown by the imaginary lines in FIG. 4 so said molten does not cool and solidified. The refractories are not damaged by the weight because the sliding board, including the steel ingots, is supported by the metal portion of the board.

According to this invention, therefore, there is no steel remaining in the runner routes. Thus, it is not necessary to disassemble and destroy the bricks of the runner routes and guide tube which is filled with solidified metal in the conventional method; it is not necessary to forcedly separate and remove solidified excess metal nor to reassemble and reconstruct the molten metal runner routes. In short, with the method of this invention there is a remarkable decrease in the work required in the ingot making operation. Furthur, in the method according to this invention the amount of refractories used is reduced to the minimum because the refractories are in contact with the molten metal only a short time since the molten metal is blocked from contact with the refractories by the pusher after completion of casting and the stopper is released rapidly; accordingly very few refractories are damaged and they can be reused many times, until they must be scrapped because of cracks, wear and tear, and erosion.

Further, in this invention refractories other than those of the sliding board need not be replaced for each charge, and as the nozzle and stopper are of replaceable construction, they can be easily replaced when they are worn out.

The above description explains one embodiment of this invention, but it is needless to say that various modifications may be conceived by those skilled in the art without departing from the spirit of the invention and that all of these modifications are to be included in the scope of this invention. Some of various modifications coming within the scope of the invention are explained below together with the contents of the embodiments in case said modifications are realized.

FIG. 6 shows a modified sliding board refractory 12', the shape of which is concentric with the sliding board bore 12 as illustrated, comprising a circular refractory with a diameter about 2.5 times that of said bore. SAid modification is used in case the direction of the movement of the sliding board is not fixed.

FIG. 7 shows a sliding board 10' simultaneously operating a set of sliding boards by means of a single action of the pusher 24, and the molten metal runner routes 34a are received in a boxlike structure 33 provided under the board 7. The center guide tube and the portions of the board 7 correspond respectively to the runner routes reaching the casting molds, which are provided equidistant from said center guide tube. Also, the casting molds are open. The openings 34 are covered by the cover 35 after the molten metal runner routes are set inside the boxlike structure with these openings. The annular sliding board 10 carrying a plurality of casting molds is provided with bores 29 into each of which a sliding board refractory 12 is inserted at a position corresponding to the open position of the runner bore 17 of the board 7, which construction the molten metal contained in the plurality of casting molds on the sliding board 10' is simultaneously locked by means of the operation of the pusher 24.

The interlocking mechanism which makes it possible to carry out in a short time the operation commencing from the starting motion of the sliding board 10 loaded with casting molds 9 filled with molten metal after completion of casting and ending with the opening of the discharging port device 23 closing the molten metal discharge nozzle 21 is shown in FIG. 9. Namely, the low voltage contacts, casting completion feeler, 27 in the cavity 9 of the mold 9 are connected in series and are guided into fixed positions on the hot top case 26. As the moltenmetal rises up after casting, contact is made and the magnetic switch 28 is actuated to operate the pusher 24 having the oil pressure ram and to move the sliding board 10 so asto block the moltenmetal, thus opening the magnetic valve 31 in the high-pressure line by means of the operation of the limit switch 30, at the time when said sliding board completes the movement by a distance equal to the diameter of the gate to actuate the pneumatic piston 32 so as to open the discharging device 23. By this interlocking mechanism the operation can be completed in, as little as l0 1 5 seconds between finishing the cast and opening the stopper.

By means of the bottom casting apparatus of this invention including eight molds as shown in FIG. 7 and FIG. 8 and the interlocking mechanism shown in FIG. 9 the representative results of casting 2.4 t-carbon steel (O.20.4 percent C.) and 5.6 1 low alloy steel were that the runner bricks 14 and the guide tube bricks 18 could be reused onaverage of 23 times, while the sliding board refractory 12 was replaced after each charge and the stopper head refractory 22 and the nozzle refractory 20 were replaced after several charges.

Referring to the construction of the discharge port switch, that shown in FIG. 2 is manually handled, whereas that shown in FIG. 9 can be electrically operated. Other mechanisms for opening and closing the discharge port by any other advantageous means can be conceived by those skilled in the art, and it is to be constructed that any such mechanism is within the category of this invention.

As to the pusher, FIG. 9 shows an electrically operated one, but any other mechanism which can be conceived by those in the art is to be included within the scope ofthis invention.

We claim:

I. An apparatus for bottom pouring steel ingots comprising, in combination: 1 v

a. a support having a horizontally extending surface and being formed with an upwardly open orifice in said surface;

b. a fountain extending upward beyond said surface;

c. runner means extending from said orifice obliquely downward and connecting said orifice with said fountain;

d. a mold assembly including a bottom plate member slidably supported on said surface, said mold assembly defining a mold cavity, and said plate member being formed with an opening therethrough communicating with said cavity;

e. valve means on the lowermost portion of said runner means downwardly adjacent said fountain for draining the latter and said runner means; and

f. operating means for moving said mold assembly between a position in which said opening and said orifices are aligned for flow of molten metal from said fountain to said cavity and a position in which said opening is sealed by said surfaces.

2. An apparatus as set forth in claim 1, wherein said plate member has a peripheral metal portion and a central portion consisting of refractory material and formed with said opening therein.

3. An apparatus as set forth in claim 2, wherein said mold assembly is moved by said actuating means in a predetermined direction and said central portion is elongated in said direction, said opening being offset from the longitudinal center of said central portion.

4. An apparatus as set forth in claim 1, wherein said mold assembly encloses a second mold cavity, and said plate memberis fonned with a second opening therethrough communicating with said second mold cavity, said support being formed with a second upwardly open orifice, said second orifice and said second opening being aligned in said position of said mold assembly, said runner means connecting said second orifice with said fountain.

5. An apparatus as set forth in claim 4, wherein said support includes a plate-shaped table member, and said runner means include a box extending under said table member and communicating with aid orifices and said fountain.

6. An apparatus as set forth in claim 1, further comprising sensing means for sensing the filling of said cavity with molten metal to a predetermined level, and actuating means operatively interposed between said sensing means and said operating means for causing said mold assembly to be moved away from said position thereof by said operating means in response to the sensing of said filling by said sensing means.

7. An apparatus as set forth in claim 6, further comprising additional sensing means for sensing the completion of movement of said mold assembly away from said position, and valve actuating means operatively interposed between said additional sensing means and said valve means for opening the latter in response to the sensing of said completion by said addition sensing means.

Claims

1. An apparatus for bottom pouring steel ingots comprising, in combination: a. a support having a horizontally extending surface and being formed with an upwardly open orifice in said surface; b. a fountain extending upward beyond said surface; c. runner means extending from said orifice obliquely downward and connecting said orifice with said fountain; d. a mold assembly including a bottom plate member slidably supported on said surface, said mold assembly defining a mold cavity, and said plate member being formed with an opening therethrough communicating with said cavity; e. valve means on the lowermost portion of said runner means downwardly adjacent said fountain for draining the latter and said runner means; and f. operating means for moving said mold assembly between a position in which said opening and said orifices are aligned for flow of molten metal from said fountain to said cavity and a position in which said opening is sealed by said surfaces.

4. An apparatus as set forth in claim 1, wherein said mold assembly encloses a second mold cavity, and said plate member is formed with a second opening therethrough communicating with said second mold cavity, said support being formed with a second upwardly open orifice, said second orifice and said second opening being aligned in said position of said mold assembly, said runner means connecting said second orifice with said fountain.