US2450989A - Method and mold for casting blastfurnace salamanders - Google Patents

Description

w. J. REES 2,450,9

METHOD AND HOLD FOR CASTING BLAST-FURNACE SALAMANDERS Gct. 12, 1948.

2 Shets-Sheet 1 Filed June 19, 1944 I" I INVENTOR k MOW/607d Rees File d June 19, 1944 Oct; v v w. J. REES 2,450,989

METHOD AND MOLD FOR CASTING BLAST-FURNACE SALAMANDERS 2 Sheets-Sheet 2 MOW/29m Rees E INVENTOR wmbu Patented Oct. 12, .1948

METHOD AND MOLD FOR CASTING BLAST- FURNACE SALAMANDERS William J.

Rees, Trenton, Mich, asslgnor to National Steel Corporation, a corporation of "Delaware Application June 19, 1944, Serial No. 541,05 8

This invention relates to the disposition of the salamander or pool of metal accumulating at the base of a blast furnace over the period of its 'use.. This pool of metal is generally removed from the furnace when it is taken out of blast as for the purpose of rebuilding the lining.

It 'has been found to be desirable to remove the salamander =by draining it from the base of the furnace while it is 'still molten because of the resultant saving in time and labor as compared with the previous practice of permitting the salamanderto freeze and then blasting it out. The disposition of the metal comprising the salamander, however, still presents a serious problem since it may amount to as much as 1000 tons which is several times the amount withdrawn from the iron notch at each tapping of the furnace while it is in normal operation. It has been proposed heretofore to collect the metal in refractory lined containers fabricated from steel plate and equipped with water-cooled refractory-covered studs, but, even where this practice is followed, it is necessary to blast the metal from these containers after it freezes and the containers are destroyed in the process, thus making it quite costly. The prevailing practice 3 Claims. (01. 22-131) is to drain the salamander into sand molds'of such size, say 2' square and 8" deep, that the blocks molded therein may be readily handled and charged as scrap into the doors of openhearth furnaces. of metal involved and the limit on the size of the blocks formed in this practice, considerable ground area (which is always at a premium around a blast furnace) is required to provide a bed having the required number of molds. Much of the area of the bed is taken up by the mold walls which are fairly thick, tapering in a given case from about 15" wide at the base to about 7"at the top. This practice also involves the construction of large footage of such walls consuming much time and labor.

I have invented a novel method for disposing of the salamander which-materially reduces the ground area required as well as the time and labor necessary for constructing the mold walls. In a preferred practice, I provide a bed of molds of a size several times that of the largest piece of scrap which can be conveniently charged into an open-hearth furnace. In a. particular in-.

stance, the molds were made about 8' square and 15" deep. The molds are preferably made in the ground and the walls or partitions therebetween built of sand. In the-molds I dispose upstanding cores in spaced relation, adapted to Because of the large amount readily :be broken by a skull cracker into pieces which can be easily handled and charged into open-hearth furnace doors of conventional size. Further details, novel features and advantages of the invention will be pointed out during the following complete description and explanation which refer to the accompanying drawings illustrating a bed of molds constructed in. accordance with the invention. In the drawings,

Figure l is-a horizontal section through the hearth of a' blast furnace, showing in plan a grid orbed of molds appropriately positioned to re-, solve the metal composing the salamander;

Figure 2 is a partial section taken generaily along the plane of line 11-11 of Figure 1;

Figure 3 is a partial section showing a. portion of Figure 2 to enlarged scale;

Figure 4 is a partial section through a plurality of molds taken along the plane of line IV-IV of Figure l;-

Figure 5 is a transverse section through the mold bed taken along the plane of line V-V' of Figure '1;

Figure 6 is a partial section taken transversely of the runner or. trough distributing the hot metal among the several molds taken along the plane of line VI-VI of Figure l;

Figure 7 is a partial section taken along the planes of line VII-VII of Figure 1, showing a conduit between the blast furnace and the runner;

Figure 8 is a partial section taken alongith'e plane of line VIII-VIII of Figure 7; g I t Figure 9 is a plan view of one of the blocks cast in the molds; and, Figure 10' is a similar view showing a block havinga modified form of core.

Referring in detail to the drawings, a blast-furnace hearth indicated at H) rests on a suitable foundation II which also carries columns l2 supporting the super-structure. The metal composing the salamander l3 accumulates on the hearth during the operation of the furnace, below the iron notch from which the day-to-day output of the furnace is tapped. A passage l4 extending downwardly and radially from the center of the hearth permits the salamander to be removed while still molten, when the furnace is taken out of blast for any reason, such as the necessity for rebuilding the lining. The passage l4 may be provided when the furnace lining is originally constructed and closed by a suitable plug. If such a passage has not been provided in the construction of the original lining, it is drilled into the hearth from the exterior of the foundation. The passage l4 discharges molten metal from the furnace int-o a conduit l5 defined by spaced walls I6 and a refractory-lined bottom I1.

In order to accommodate the molten metal forming the salamander, I form a bed or grid of molds i 8 preferably located side by side in two spaced rows so they may be conveniently supplied with metal from a central runner I8. The molds and runner are formed in the ground by building up sand walls 20 and 2|. The walls 2| are provided with vent holes 2la. spaced therealong, as shown in Figure 6. The mold bed may be located in the bottom of the slag pit customarily provided in close proximity to the furnace, any accumulation of slag deposited therein being removed to permit the formation of the molds and runner. The bottom of the slag pit is located well below the bottom of the furnace hearth and thus permits the mold bed and runner to be formed with an appropriate downward slope, as shown in Figure 2. The walls of the runner are notched adjacent each mold as at 22 to permit flow of metal from the runner into the molds.

Gates 23 are disposed adjacent the notches on the lower side. These gates are composed of a piece of plate cut to suitable size and shape provided with a bar 24 welded thereto adapted to 'erve as a handle. Each gate is supported by a crossbar 25 embedded in the walls of the runner and has a layer of sand 26 protecting its surface from contact with the hot metal. A wire 21 welded to the bar 24 of each gate is carried off to one side of the bed, as shown in Figure 2, and preferably over the wall 28 of the slag pit. By means of these wires, the gates 23 may be successively removed from a distance as the several pairs of molds are filled.

The molds l8 are of substantial size, approximately 8 square and about 15" deep. In order to facilitate breakage of blocks of iron of this size, I place upstanding cores 29 in spaced relation in each mold.' These cores may be simply hollow stakes, i. e., lengths of scrap pipe driven into the ground in spaced relation and then filled with sand. The holes in the cast blocks formed by the cores 29 permit them to be broken by a skull cracker into pieces of convenient size for handling and charging into an open-hearth furnace.

It will be understood that the mold bed and runner are made ready for receiving the salamander before the passage [4 is drilled through the bottom of the furnace hearth, or if it already exists, before breaking through the closure which prevents leakage during the normal operation of the furnace. The salamander, of course, must be maintained in molten condition until the mold bed has been prepared. Upon completion of the passage I4 or on breaking through its sealing plug, the metal quickly fiows through the passage and the conduit l5 and thence into the runner l9. As each pair of molds I8 is filled with metal to the desired depth, the adjacent gate 23 is removed, permitting the metal to flow on down the runner and divide between the next two molds.

The total area of the mold bed, of course, willbe made of sufiicient size to accommodate the maximum tonnage of metal which may have accumulated in the salamander.

When the salamander has been cast and the metal cooled sufficiently, the resulting slabs, such as that indicated at 30, are removed and subjected to heavy impact blows as by means of a skull cracker. The holes 3| formed in the slabs 30 by the cores 29 provide preferred cleavage planes so that the slabs may be easily broken into fragments of a size suitable for handling and charging into the open hearth as before stated. Figure 9 illustrates roughly the fragmentation of a slab under the blows of a skull cracker.

Figure 10 illustrates a block cast by a slight modification of the practice described above. The slab 30 has cores 32 therein composed of lengths of angles welded together forming tubes of square cross section. Such tubes form holes with sharp comers and thus facilitate the breakage of the slabs even more than the round holes formed by cores made of scrap pipe.

It will be apparent that by casting the salamander into slabs of a size as large as approximately 8' square, I am able to reduce materially the number of walls between the molds and also to eliminate any feeder runners branching from the main stream. The advantage of this is twofold, as already indicated. In the first place, the elimination of intermediate partitions reduces the total casting area required to accommodate the entire mass of a salamander. In the second place, there is the saving of time and labor required to construct these intermediate partitions. The cost of providing the cores 29 is very small since they are composed of scrap material which would eventually reach the open-hearth furnace in any case, and the labor involved in driving them and filling them with sand is slight.

Although I have illustrated and described but a preferred arrangement of the mold bed and the practice of casting the salamander, it will be understood that changes in the construction or procedure described may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. In a method of disposing of a blast-furnace salamander, the steps including preparing a bed of sand molds each of which is of a size larger than that desired in pieces of scrap, driving lengths of pipe into the bottoms of the molds in spaced relation, filling the pipe lengths with sand, running the metal composing the salamander into said molds, thereby forming blocks susceptible to breakage into pieces of a size suited for easy charging as scrap, and breaking the blocks into such pieces by impact blows.

2. In a method of disposing of blast-furnace salamander, the steps including preparing a bed of sand molds each of which is of a size larger than that desired in pieces of scrap, driving hollow stakes into the ground in said molds in spaced relation to provide upstanding hole-forming cores, filling the stakes with sand, running the metal composing the salamander into said molds, thereby forming blocks susceptible to breakage into pieces of a size suited for easy charging as scrap, and breaking the blocks into such pieces by impact blows.

3. A mold adapted to accommodate the metal constituting a blast-furnace salamander, comprising a bed at a level below the bottom of the furnace hearth, spaced wallsbuilt up on the bed, said walls forming a plurality Qf separate molds, a

runner alongside the molds, hollow stakes ex tending upwardly from the bed in spaced relation within said molds, and a sand filling in said 5 stakes to provide cores for forming holes extending through the blocks cast in the molds.

vrnzrlulilr J. REES.

REFERENCES CITED The following references are of record. in the file of this patent:

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