US3151200A - Ladle lining apparatus - Google Patents

Description

Sept. 29, 1964 D. B. SPENCER 3,151,200

LADLE LINING APPARATUS Filed May 7, 1962 2 Shams-Sheet 1 INVENTOR. n' W 42 ac Jain?! 3 DONALD B. 5pm,

Sept. 29, 1964 D. a. SPENCER 3,151,200

LADLE LINING APPARATUS Filed May 7, 1962 2 Sheets-Sheet 2 M I l INVENTOR. DONALD 8. SPENCER Attorney United States Patent 3,151,200 LADLE LINING APPARATUS Donald B. Spencer, Portland, Greg, assignor to Guy F.

Atkinson Company, San Francisco, Calif., a corporation of Nevada Filed May 7, 1962, Ser. No. 192,867 16 Claims. (Cl. 26643) This invention relates to an improved apparatus for lining ladies and the like used in handling molten metal.

The present apparatus comprises a chill form having an exterior shape corresponding roughly to the interior contour of the conventional refractory brick lining in a ladle but slightly smaller than the ladle cavity to leave a small space between the exterior surface of the chill form and the interior surface of the brick lining. In the use of the apparatus the chill form is inserted into the ladle cavity and a suitable molten refractory material such as slag is poured into the space between the chill form and the brick, the slag being frozen in place by the cooling effect of water circulated through the chill form. When the molten slag has solidified, the chill form is removed leaving a cavity in the ladle of the same shape and contour as the chill form. Such a slag lining may be applied to new ladles or new brick linings to provide an interior surface of slag rather than brick and it may also be applied as a repair to brick or slag linings which have been eroded away in service.

This method of lining ladles is described and claimed in my prior Patent No. 2,894,739, issued July 14, 1959. The present invention involves improvements in the apparatus in order to produce a better lining and to reduce the cost of lining ladles.

While the present invention is not limited to ladles used in the handling of certain metals, it is of particular advantage in the steel industry and especially in the production of ferro alloys which subject the ladle lining not only to ordinary mechanical erosion but also chemically attack all surfaces of the lining which they touch.

The chill form itself is also especially subject to deterioration in the pour areas on its upper side where the molten slag is poured over the chill form in lining a ladle since the slag is at a temperature in the range between 2400 F. and 3200 F. In fact, experience shows that the life of the chill form is limited only by the life of the surface areas where the incoming molten slag impinges and flows down the side of the contoured mold. The high thermal gradient and extremely rapid ternperature changes experienced by the metal in these areas induce changes in its crystalline structure. The fine grain of the original steel in the chill form is transformed after many uses to a coarse grain structure and upsetting of the crystalline structure in the direction of the thermal gradient also occurs. As a result the inter-granular tightness of fit gradually diminishes and actual fissures open up at the crystal grain boundaries.

The general object of the present invention is to provide apparatus which will reduce the ladle lining cost per ton of metal produced.

In order to achieve the foregoing general object, important ancillary objects are to provide apparatus which will produce a ladle lining with a longer service life than the linings heretofore provided and to increase the life of the chill forms used.

Other objects are to provide apparatus which will produce a slag lining in a more desirable condition for resistance to the destructive effects of high temperature and mechanical and chemical erosion, a slag lining having a glass smooth surface, a slag lining having a line grained crystalline or amorphous texture, a high cooling rate in the molten slag, a high rate of heat transfer "ice through the wall of the chill form, an improved chill form of steel plate of uniform thickness, and an improved water circulation within the chill form to produce a high velocity sheet-like liquid flow along the inner wall surfaces which wipes the surfaces clean of any film of gas.

The present water cooling system makes possible the fabrication of the chill form from relatively thin steel plate of uniform thickness at lower cost than a cast steel chill form. This, in turn, provides a maximum rate of heat transfer through the chill form for rapid cooling of the slag. When the slag is cooled rapidly in this manner it has a glass smooth surface with a fine grained crystalline texture to considerable depth. This condition of the slag imparts greatly improved resistance to chemical as well as mechanical erosion whereby the ladle lining has a long life.

Notwithstanding the thin wall form of construction, the improved cooling results in a much longer life for the present chill form than can be achieved with a more expensive and thick walled cast chill form without the present cooling arrangement. The chill form preferably has four supporting arms to impart adequate strength and stability to the structure. This arrangement also provides four different pouring areas between the supporting arms whereby the wearing effects of the poured slag may be distributed uniformly over the whole top of the chill form in order to obtain the maximum useful life of the chill form. Although the chill form illustrated herein is circular in shape, it may be made in various other shapes to conform to different ladles. The present apparatus is of particular advantage for use in ladles where highly reactive metallurgical reductions are performed in the ladle itself.

The foregoing and other objects and advantages will become apparent and the invention will be better understood from the following detailed description of certain preferred embodiments of the invention illustrated in the accompanying drawings. Various changes may be made, however, in the construction and arrangement of parts and all such modifications Within the scope of the appended claims are included in the invention.

In the drawings:

FIGURE 1 is a side elevation view with parts in section, showing the present apparatus in a ladle after a molten refractory lining has been poured;

FIGURE 2 is a fragmentary View taken on the line 2-2 of FIGURE 1;

FIGURE 3 is a top plan view of the chill form;

FIGURE 4 is a sectional view of the chill form taken on the line 44 of FIGURE 3, showing one form 0 water distributing means;

FIGURE 5 is an enlarged fragmentary view taken on the line 5-5 of FIGURE 4;

FIGURE 6 is an enlarged sectional view of the water distributing cone shown in FIGURES 4 and 5;

FIGURE 7 is a sectional view of a modification;

FIGURE 8 is an enlarged sectional view of the bottom portion of FIGURE 7; and

FIGURE 9 is a fragmentary sectional view showing slightly different shape of chill form.

FIGURE 1 shows a chill form 10 embodying the principles of the invention applied to a typical ladle 11 used in the manufacture of steel. The ladle 11 comprises a metal outer casing 12 containing a brick lining 13. The ladle is conventional except for the addition of a riser member 14 at the top and centering lugs 15 on the usual lifting trunnions 16 in order to accommodate the chill form. The ladle also has the usual pouring lip 17. In the present illustration the brick lining 13 is in new condition with an outer layer of insulation brick and inner layers or courses of refractory brick.

In the use of such ladles the brick lining is rather rapidly worn away by the combined effects of mechanical erosion and chemical action as previously explained, whereby frequent repair becomes necessary. It is desirable to use molten slag for the repair of badly eroded linings since this slag is always available as a waste product at the steel or ferro alloy producing smelters and can be installed quickly and at low cost by the present apparatus. The use of molten slag or other suitable molten refractory is not limited to the repair of badly eroded linings, but also, as shown in FIGURE 1, can be applied as'an auxiliary or inner lining or backing on a new brick lining. The chill form is accordingly made to a shape corresponding to the shape of the usable cavity in the ladle and having suitable dimensions to allow a space all around the chill form for the introduction of the molten slag 20. In this manner the brick lining is protected by a thinner layer of material which is more resistant to both mechanical and chemical erosion. Also, if desired, the brick lining may be omitted and the entire lining formed of slag or other suitable molten refractory.

For use in a circular ladle the present chill form is of pear shape as shown in FIGURE 4. It has a flat, or approximately flat, bottom wall 25, a rounded bottom corner 26, and a conical side wall 27 rising somewhat beyond its mid height. The conical wall 27 may extend to the outward and downward sloping annular conical wall portion 3t) which surrounds the central fiat wall portion 29. If desired, a wall portion 28, with a taper less than wall 27, can be interposed between wall 27 and wall portion 39. The simpler form shown in FIGURE 7 9, in which wall portion 27a extends to wall 3%, is preferred. These wall portions are preferably fabricated by welding together sections of rolled steel plate of uniform thickness to form a closed hollow shell. It is, of course, understood that the shape of the chill form is dictated by the shape of the ladle. For use in an oval ladle, for example, the chill form would be oval instead of circular in cross section but it would still be generally pear-shape.

The hollow chill form just described is supported in depending position Within the ladle by an overhead bracket or frame assembly generally indicated at The frame forms a spider having in this instance four hollow radial arms 36'as shown in FIGURE 3. Each arm 36 is connected with the conical top portion 36) by a pair of vertical radial gusset plates 37. Theouter ends of two of the arms. are equipped with an upright 38 braced to the arm by means of a pair of vertical gusset plates 39. The upper end of each upright 38 is equipped with an eye '40 to receive a lifting bail from an overhead crane.

The outer end of each arm 36 is also equipped with a downwardly projecting bifurcated locating guide 41 having a pair of divergent fingers 42 to straddle the centering lug 1 5 on the ladle. Preferably, the ladle is equipped with four centering lugs 15 and the supporting bracket 35 has a locating guide 41' for each centering lug.

The centering lugs may be mounted between the lifting trunnions 16, if desired, in order to orient the arms 36 I to the most convenient positions. Thus, the arms 36 are adapted to rest on the annular spacer or riser 14 which can be made of a channel and which locates the chill form properly in a vertical direction while the locating guides 41.center the chill form laterally in the ladle. For this purpose the guides 41. are located so as to have only a small clearance space outside of riser 14 which corresponds to the widest dimension at the top of the tapered ladle. Riser 14 may be attached to the top of the ladle or it may merely rest on the ladle during a lining operation, In some casesthe riser is not used, the gusset plates 37 being made shorter so that arms 36 will rest directly on-top of the ladle. with water the form as a whole has sutlicient weight so 1 that it is not buo'yantj in molten slag, or other suitable molten refractory20.

When chill form shell it; isfilled.

Each hollow arm 36 contains therewithin a water inlet pipe 45 and a water outlet pipe 46. The projecting ends of these pipes are threaded, the pipes in three of the arms being provided with caps 47. When slag is being poured to line or re-line a ladle it is preferably poured into a zone corresponding to a single quadrant on one side of the ladle between two adjacent arms 36. This quadrant of the sloping top wall portion 30 then becomes a pouring area between the two web plates 37, the molten slag running off this area and into the space between the chill form and the ladle lining. The'caps 47 are left on the pipes in the arms adjacent to the pouring area, and the caps are removed from the pipes in one of the op-. posite arms. The uncapped pipes are then connected with an external water supply source and water disposal means whereby the external connections and their associated conduits are out of the way of the slag pouring operation. Each time the chill form is used, two of the caps 47 are shifted from capped pipes to uncapped pipes, and the external water connections are made at the newly uncapped pipes. Thus, the uncapped pipes will designate the quadrant which received the last slag pour whereby the pour may be shifted from quadrant to quadrant around the chill form to distribute the wear on the top wall portion 39, this being the portion of the chill form receiving the greatest wear in the use of the apparatus.

The four inlet pipes 45 are connected to a vertical pipe 5t which projects through the top center wall 29 of the chill form. The four outlet pipes 46 communicate through the top wall 29 but do not. project below this wall in order to avoid trapping air in the top of the chill form. Thus, there are four separate outlets 51 in the top of the chill form, only one of which is effective in any given operation by reason of the fact that the other three pipes 46 are capped at 4'7.

The vertical portions of pipes 46 and 50 above top. shell plate 29 are enclosed and protected against slag pour by a vertical cylindrical plate 7%. Central top and bottomhorizontal plates 71 and 72 connect the four arms together to stiffen the supporting frame and provide suspension means for a single central lifting eye 73'. The eye '73 may be provided in addition to lifting eyes 49 or either one of these lifting means may be omitted, if desired.

In order to accommodate expansion and contraction strains in the chill form shell the inlet pipe 50 is provided with a lateral U-bend 52. The lower end of pipe 5f projects into a generally conical inverted cup 55 which 7 forms a distributing head, the upper end of this cone or cup being welded to the pipe at 56. Within the cone 55 the pipe 50 is provided with a plurality of outlet openings 57. The lower edge or rim of cone 55 is welded at 53 on top of a plurality of spacing rods or bars 59 which are in turn welded to the bottom plate 25 of the chill form. This arrangement leaves a narrow annular openslot 69 of considerable length around the periphery of the lower end of cone 55 to distribute the incoming water in a thin sheet equally in all radial directions to the side wall of the chill form, the cone being located in the center of the bottom plate.

In operationthe cooling water is introduced with sufficientvelocity to produce a sheet-like flow that is circumferentially and uniformly distributed over a zone which extends outwardly over the rounded bottom corner 26 and up along the inner surface of. the sloping side wall 27, and also continuing along the surface 28 as in- V dicated by arrows 61. This sheet-like flow has sufficient velocity to remove and, in fact, to prevent the formation of, insulating gas bubbles on the inside surface of the chill form which would impede efiicient heat transfer through the steel plate wall. Care is taken to impose no back pressure or other restriction on the outlet stream which would tend to reduce the velocity of flow.

In order to, avoid excessive temperature difference between the inside and outside surfaces. of the shellwalL'the water is preferably introduced into the chill form at a temperature between 70 F. and 140 F. In this temperature range the steel plate is maintained above its transition temperature to provide conditions for the ductile behavior of the plate under the shock of the high temperature slag as distinguished from a brittle behavior which would occur with the use of colder water.

FIGURES 7 and 8 illustrate a modification in which the chill form 3% is the same as that shown in FIGURE 4 except that it lacks the elongated inlet pipe 50 and water distributing cone 55. Instead, there is provided an interior thin walled shell $1 which is maintained at a uniform distance from the inside surface of the outer shell by means of a plurality of spacers 82. Preferably, the inner shell 81 is fabricated from sections of steel plate in the same general manner as the outer shell, the spacers 82 being welded in place between the two shells as the fabrication proceeds. The space between the outer and inner shells, indicated at 83, may be, for example, in the order of one inch. The shape of the shells may be simplified by omitting the intermediate conical section 28 as shown in FIGURE 9.

The four outlet pipes 46 are connected as previously described to provide four outlet openings 51 in the top plate 29 of outer shell 35). The inlet pipe 50a continues through the inner shell 81 and terminates just inside the top wall thereof. Thus, the inner shell is maintained full of water with the water escaping through a central bottom outlet opening 84.

The water escaping from outlet 84 flows radially in all directions from this central point across the bottom 25, up along the side walls 27 and 23 and then returns inwardly across sloping top Wall portion 30 to the outlet opening 51 which is available to carry off the water. in this way the sheet-like how is maintained along all portions of the inside surface of the outer shell and also across the pour areas of top wall portion 36. Inner shell 81 forms a water distributor maintaining this regimen of flow for maximum heat transfer and minimum turbulence. During its travel through the narrow space 83 this flow of cooling water receives heat from the molten slag in the ladle and carries the heat away in the outlet stream.

When the cooling water is distributed for sheet-like flow as above described, the molten slag in contact with the outside surface of the chill form is cooled and solidified quickly to produce a smooth glassy surface which aliords the best resistance against thermal, mechanical and chemical attack from molten steel. Moreover, the crystalline grain structure of the slag beneath the glassy surface is of very fine texture as a result of rapid cooling, which enhances the durability and long life of the whole thickness of the slag lining.

At the same time, the efficient cooling of the relatively thin shell walls prevents rapid deterioration of the crystal line grain structure of the steel plate. For example, in a chill form shell eight feet high and six feet in large diameter, the steel plate wall in contact with the molten slag is only three-fourths of an inch thick. On the top of the shell the radial gusset plates confine each slag pour to a bounded area so that by progressively shifting the pour area from quadrant to quadrant all top areas will receive equal wear for the longest possible service for the apparatus.

Having now described my invention and in What manner the same may be used, what 1 claim as new and desire to protect by Letters Patent is:

1. A ladle lining apparatus comprising a tapered hollow shell having top and bottom walls and a sloping side Wall with a rounded transition between said bottom and side walls, means to suspend said shell in centered position in a ladle containing molten slag and the like, a Water outlet in the top of said shell, a water inlet pipe extending through the top of said shell, and water distributing means comprising a wall extending over at least the central portion of said shell bottom wall in spaced relation thereabove, said inlet pipe being arranged to introduce cooling water into said space between said walls and said distributor wall being arranged to direct a thin sheet-like flow of water in all radial directions outwardly from the bottom center portion of said shell and sweeping upwardly along the side wall of the shell toward said top outlet so that said bottom and side Walls of the shell are cooled by a high rate of heat transfer directly to said sheet-like flow of water from said inlet pipe.

2. Apparatus as in claim 1, in which said water distn'buting means comprises a hollow inverted cup, the base edge of said cup being spaced a short distance above the bottom of said shell to form a narrow annular slot-like orifice and the upper portion of said cup being connected With said water inlet pipe.

3. Apparatus as in claim 2, including a plurality of spacer blocks under said base edge of said cup defining the width of said orifice, said spacer blocks being welded to said base edge of said cup and to the bottom of said shell.

4-. Apparatus as in claim 1, in which said water distributing means comprises a hollow shell spaced within said first shell to confine said sheet-like flow against the inner surface of said first shell.

5. Apparatus as in claim 4, in which the top of said inner shell is connected with said inlet pipe and the bottom of said inner shell has a bottom outlet opening communicating with the space between said shells.

6. Ladle lining apparatus comprising a tapered hollow shell having top and bottom walls and a sloping side Wall with a rounded transition between said bottom and side walls, a support for said shell comprising a plurality of radial arms connected with the top of the shell and adapted to be supported on the rim of a ladle and to suspend said shell within a ladle containing molten slag and the like, water inlet and outlet pipes extending along said arms, the inner ends of said outlet pipes communicating with the interior of said shell at the top thereof to provide outlet means in said shell, water distributing means extending over at least the central portion of said shell bottom wall and arranged to direct a thin sheet-like flow of water in all radial directions outwardly from the bottom center portion of said shell and sweeping upward along the side wall of the shell to said top outlet means so that said bottom and side walls of the shell are cooled by a high rate of heat transfer directly to said sheet-like fiow of water from said inlet pipe.

7. Ladle lining apparatus comprising a generally pearshaped hollow shell for molding molten slag and the like in a ladle, a plurality of hollow radial supporting arms, vertical radial gusset plates connecting said arms with the top end of said shell, cooling water inlet and outlet pipes in said arms for circulating water through said shell, and water distributing means in the bottom of said shell connected with said inlet pipes, said distributing means extending over at least the central portion of the bottom of the shell forming a narrow annular slot-like discharge orifice arranged to direct a thin sheet-like non-turbulent flow in all radial directions outwardly from the bottom center of said shell and sweeping upwardly along the side wall of the shell so that said bottom and side Walls of the shell are cooled by a high rate of heat transfer directly to said sheet-like flow of water from said inlet pipe.

8. A chill form ladle liner for molding molten slag and the like in a ladle comprising a generally pear-shaped hollow shell, a plurality of hollow radial supporting arms, vertical radial gusset plates connecting said arms with the top end of said shell, cooling water inlet and outlet pipes in said arms for circulating water through said shell, a water distributing inverted cup in the bottom of said shell connected to said inlet pipes, and means securing the rim of said cup spaced slightly above the bottom of said shell to provide a narrow annular slot-like discharge orifice for the water.

9. A chill form ladle liner for molding molten slag and the-like in a ladle comprising a generally pear-shaped hollow shell; said shell comprising a fiat central top plate anda flat bottom plate, an annular conical top plate surrounding said central'top plate, and a conical side wall plate; water outlet means in the top of said shell, and cooling water inlet and distributing means Within said shell extending over at least the central portion of said shell bottom plate and arranged to direct a thin sheet-like flow in all radial directions outwardly from the bottom center portion of said shell and sweeping upwardly along the side wall of the shell so that said bottom and side Walls of the shell are cooled by a high rate of heat transfer directly to said sheet-like flow of water from said inlet pipe.

10. A chill form ladle liner comprising a hollow outer shell, means to suspend said shell in centered position in a ladle containing molten slag and the like, a hollow inner References Cited in the file of this patent UNITED STATES PATENTS 813,405 Cook et al Feb. 27, 1906 1,017,969 Harris Feb. 20, 1912 2,894,739 Spencer July 14, 1959 FOREIGN PATENTS 946,233 France Mar. 3, 1947

Claims (1)

1. 7. LADLE LINING APPARATUS COMPRISING A GENERALLY PEARSHAPED HOLLOW SHELL FOR MOLDING MOLTEN SLAG AND THE LIKE IN A LADLE, A PLURALITY OF HOLLOW RADIAL SUPPORTING ARMS, VERTICAL RADIAL GUSSET PLATES CONNECTING SAID ARMS WITH THE TOP END OF SAID SHELL, COOLING WATER INLET AND OUTLET PIPES IN SAID ARMS FOR CIRCULATING WATER THROUGH SAID SHELL, AND WATER DISTRIBUTING MEANS IN THE BOTTOM OF SAID SHELL CONNECTED WITH SAID INLET PIPES, SAID DISTRIBUTING MEANS EXTENDING OVER AT LEAST THE CENTRAL PORTION OF THE BOTTOM OF THE SHELL FORMING A NARROW ANNULAR SLOT-LIKE DISCHARGE ORIFICE ARRANGED TO DIRECT A THIN SHEET-LIKE NON-TURBULENT FLOW IN ALL RADIAL DIRECTIONS OUTWARDLY FROM THE BOTTOM CENTER OF SAID SHELL AND SWEEPING UPWARDLY ALONG THE SIDE WALL OF THE SHELL SO THAT SAID BOTTOM AND SIDE WALLS OF THE SHELL ARE COOLED BY A HIGH RATE OF HEAT TRANSFER DIRECTLY TO SAID SHEET-LIKE FLOW OF WATER FROM SAID INLET PIPE.

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