US3754590A

US3754590A - Method of making and using a continuous casting chill basket

Info

Publication number: US3754590A
Application number: US00245230A
Authority: US
Inventors: R Cashdollar
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-04-18
Filing date: 1972-04-18
Publication date: 1973-08-28
Anticipated expiration: 1990-08-28

Abstract

There is disclosed a chill basket for the chill mold of a continuous casting line and a method of making a chill basket. The chill basket is formed of like L-shaped perforated sheets, each sheet having a lip at the end of its foot. The chill basket is formed at the site of the line, or partly or wholly in the mold, by securing the lip of each sheet with a nut and bolt or Dzus fastener or kindred fasteners to the end of the leg of the other sheet. The fasteners are inserted through the end of the leg of each sheet in the direction towards the lip of the other sheet and away from the wall of the chill mold so that the end of the fastener does not protrude towards the mold wall presenting the hazard that it may perforate the wall and permit the cooling water to penetrate into the molten steel.

Description

Elite States Patent [191 Cashdollar, Sr.

[ 1 Aug. 28, 1973 [22] Filed:

[ METHOD OF MAKING AND USING A CONTINUOUS CASTING CHILL BASKET [52] 11.8. C1 164/1, 164/82, 164/274 [51] Int. Cl B2211 11/08 [58] Field of Search 164/1, 82, 137, 274,

Primary Examiner-R. Spencer Annear Attorney-Hymen Diamond et al.

[57] ABSTRACT There is disclosed a chill basket for the chill mold of a continuous casting line and a method of making a chill basket. The chill basket is formed of like L-shaped perforated sheets, each sheet having a lip at the end of its foot. The chill basket is formed at the site of the line, or partly or wholly in the mold, by securing the lip of each sheet with a nut and bolt or Dzus fastener or kindred fasteners to the end of the leg of the other sheet. The fasteners are inserted through the end of the leg of Illlllll/ [56] References Cited each sheet in the direction towards the lip of the other UNITED STATES PATENTS sheet and away from the wall of the chill mold so that 3,266,104 8/1966 Foldessy et a1. 164/274 the gnd of the fastener does not protrude towards the mold wall presenting the hazard that it may perforate au er ac 3,612,150 10/ 1971 Rossi 164/82 the cooling water to penetrae ""0 3,692,091 9/1972 Saxer 249/206 X 4 Claims, 6 Drawing Flgures n I 4 7 7 57 is 5 OQOQOOOQQO )OO (i i i 00 ()OQOOOO ()0 5| l 600109 90600 00 l OOOICDGOOOG 0G0 I 1 I I I PATENIEU M8828 I975 SHEEI 1 BF 2 FIG.20

FIG.2b

METHOD OF MAKING AND USING A CONTINUOUS CASTING CHILL BASKET BACKGROUND OF THE INVENTION This invention relates to steel making and has particular relationship to the chilling of molten steel after it is poured in continuous casting. The molten steel is poured from a ladle into a copper water-cooled chill mold where it is progressively converted into a solidifled mass that is moved by rolls along the continuouscasting line and is converted or cut into ingots or slabs. To prevent the mold from being damaged by the sudden impact of a mass of molten steel at the start of a casting operation, a chill basket is inserted in the mold. The chill basket also accelerates the solidification of the molten steel and as a coupling for the mechanism which pulls strips through the rolls. This basket has the form of a rectangular box open along the path of the molten steel-at the top and bottom where the steel flows vertically-and having perforated walls. When the steel is first poured a pool builds up in a chill pan at the bottom of the basket; thereafter, the steel flows through the holes into the adjacent space between the basket and the walls of the mold and then fills the basket. Once the steel is solidified, the steel is moved as strip with the basket and the steel solidified around it in the lead. The basket is ultimately cut off along with the entire starting head. A chill basket is required at the start of each casting operation.

In accordance with the teachings of the prior art, the chill basket is a welded box. Typically this box is between and 6 feet long, twenty inches high and between 5 and 6 inches wide. The labor and material cost of producing such a welded box is high. In addition, this structure, because of its bulk (about five cubic feet), is difficult and very costly to ship and to store, requiring unreasonably large shipping volume and warehousing space. The structure is difficult to load for shipment and to unload from the shipping facilities. Indeed, becuase of its awkward dimensions, the prior-art box frequently collapses during shipment under the load of other boxes and because of its length is bent and broken during handling so that an excessively high percentage of the boxes must be scrapped. At times a prior-art basket which has been flexed or bent or has partly collapsed is inserted in a mold in its flexed or collapsed condition with the result that the mold may be damaged and the casting line must be restarted.

It is an object of this invention to overcome the above-described disadvantages of the prior-art chill basket and to provide a chill basket which shall lend itself to fabrication at reduced cost in labor and material, shall be readily loaded for shipment and shipped to, and stored at, the site where it is to be used, shall not be subject to damage during shipment and warehousing, shall not present the hazard of being inserted in a chill mold in damaged or deformed condition and, in general, shall not cause losses from useless or damaged units.

SUMMARY OF THE INVENTION In accordance with this invention, each chill basket is formed from a pair of like members of L section which are combined into a box-like structure at the site of the continuous-casting line. Typically there are a number of L-shaped sheets, for example pairs, on the floor of the shop near the continuous casting line from which baskets are assembled as needed. A lip extends from the foot of each member and the basket is formed by securing with a fastener, that may be readily manipulated, such as a nut and bolt or Dzus fastener or kindred fasteners, the lip of one member to the end of the leg, remote from its foot, of the other member. The basket may indeed be assembled within the chill mold or the assembly may be carried out partly near the mold and completed in the mold; this avoids damage in handling from a point, outside of the mold, where the basket may be formed before being placed into the chill mold. To preclude damage to the wall of the copper mold by the end of fasteners protruding from the corners of a chill basket, each fastener is inserted into the lip and contiguous corner in the direction away from the wall of the mold. Thus, if the fastener is a nut and bolt, Dzus fastener or kindred fasteners, the head of the fastener, rather than its protruding end, faces the directly opposite wall of the mold.

One hundred pairs of L-shaped sheets can be stored on four pallets in the same warehouse space as six of the prior-art baskets. During loading and unloading twenty-five pairs of L-shaped sheets (one pallet) are moved by each lift as compared to only six prior-art baskets.

BRIEF DESCRIPTION OF THE DRAWINGS I For a better understanding of this invention, both as to its organization and as to its method of operation, together with additional objects and advantages thereof, reference is made to the following description, taken in connection with the accompanying drawings in which:

FIG. 1 is a view in perspective of the part of a continuous-casting system which involves this invention;

FIGS. 2a and b are respectively views in end elevation and in side elevation of an assembled chill basket in accordance with this invention;

FIG. 3 is a plan view showing the chill mold with the chill basket positioned therein prior to the pouring of the molten steel;

FIG. 4 is a view in section taken along line IV-IV of FIG. 3; and

FIG. 5 is a plan view of the mold chill pan.

DETAILED DESCRIPTION OF INVENTION The apparatus shown in FIG. 1 is the pertinent portion of a continuous casting system 11. This apparatus includes a chill-mold 13 into which molten steel is poured from a ladle 15 through a tundish 17.

The ladle l5 typically containing about 200 tons more or less of molten steel is delivered from the basic oxygen furnace shop to the casting apparatus 11. To maintain the casting line in continuous operation, one large ladle 15 or two ladles 15 in rotation are typically delivered. Each ladle 15 may be subjected to degassing by vacuum degassing units (not shown) and is then lifted by a hoist (not shown) onto a bracket 19 in a ladle-positioning car 21. The ladle 15 is positioned in the car 21 in pouring position over the tundish 17 which is also carried by the car 21 to the position over the mold 13. Where one ladle 15 is used the line is usually started anew for each ladle; where two ladles in rotation are used the line runs continuously until the operation is stopped. The former practice usually demands more chill baskets than the latter.

The chill mold 13 (FIGS. 3 and 4) is composed of copper and is of generally rectangular horizontal section. The mold 13 has hollow walls 23 through which a cooling fluid (water) flows. The mold 13 has a cavity 25 into which the molten steel is poured. At the start of a casting operation the mold 13 is sealed at the bottorn by a chill pan 31 which is engaged by a sealing mechanism (not shown). Coupling units 33 are sealed through the chill pan 31. Each unit 33 includes an attenuated member 35 which extends into the cavity 25 and serves as chill rod and a coupling member 37 which is grasped by a coupling device (not shown) and advanced to pinch rolls 39 which move the solidified steel strip 41 at the desired casting rate.

Within the cavity 25 there is a chill basket 45. The basket 45 is formed of like, or identical, L-shaped members 47. Each member has a leg 49 and a foot 51. A lip 53 extends from each foot 51 generally parallel to the leg 49 and in a direction away from the leg. The leg and foot have holes 55. The lip 53 and the end of the leg 49 have facilities for receiving a fastener 57. The basket 13 is formed by securing, by means of fastener 57, the lip 53 of each member 47 to the end of the leg 49, which is remote from the foot 51, of the other member. The fastener 57 may be a nut 61 and bolt 63 or Dzus fastener or kindred fastener. The fastener 57 is of a material which is not melted by the heat from the molten steel.

The basket 45 is inserted, and may in fact be partly or wholly assembled, in the cavity 25. Where the basket 45 is partly assembled in the cavity, the lips 57 are secured to the legs 49 by the lower fasteners 57. Then the partly assembled unit is inserted in the cavity 25 and the lips 57 and legs 49 are secured by the upper fasteners 57. The basket 45 rests in the chill pan 31. Typically the ends of the basket 45 (the feet 51) may be spaced about 2 inches from the end walls 23e (FIG. 3) of the mold l3 and the sides of the basket 45 (the legs 49) about inch to an inch from the side walls 23:: of the mold 13. To preclude perforation of the side walls 23s of the mold 13 by the protruding ends 67 of the bolts 63, for example by the impact of the molten steel, the bolts are inserted in the end of the leg 49 and the lip 53 in a direction away from the side walls 23s.

When the molten steel is first poured into the mold 13, it forms a pool in the chill pan 31 at the bottom of the chill basket 45. As the level of the pool rises the basket 45 prevents the whole mass of metal from being thrust against the walls 53 of the mold 13 and damaging the mold. The metal in limited quantities flows through the holes 55 into the space between the basket 45 and the wall 23. After this space is filled the molten steel is confined to the basket. When the metal in the mold reaches a plastic condition the movement of the mass of metal is started by engagement of rolls (not shown) with the coupling members 37. The plastic metal then passes to the pinch rolls 39 where it is advanced at the desired speed. Along the line, the end of the strip 41 including the basket 45 which has been fused into the plastic mass is cut off by a traveling cut-off torch. Thereafter, the strip is cut into slabs.

While a preferred embodiment and mode of practice of this invention has been disclosed herein, many modifications thereof are feasible. This invention is not to be restricted except insofar as is necessitated by the spirit of the prior art.

I claim:

1. The method of providing a chill basket for a chill mold of a continuous casting line, the said method comprising, making like perforated members, each member being of generally L section with a lip at the end of the foot of the L, joining said members near the site of said line by connecting by means of a fastener the lip of each to that end of the leg of the other which is remote from the foot to form an open rectangular box with the sides of the box perforated, and inserting said box into said mold so that the open faces of the box are in the path of the steel.

2. The method of claim 1 wherein the members are secured together by fasteners passing through the respective lips and ends, the fasteners being inserted from the side of the joint remote from the lip to preclude damage to the mold by protruding ends of fastenrs.

3. The method of providing a chill basket for a chill mold of a continuous casting line, the said method comprising, making like perforated members, each member being of generally L section with a lip at the end of the foot of the L, inserting a pair of said members in a mold with the lip of one member contiguous to the end of the leg, remote from its foot, of the other member, and joining the members of said pair within the mold by connecting, by means of a readily manipulable fastener, the lip of each member of the pair to the contiguous end of the leg of the other member of the pair.

4. The method of claim 3 wherein the pair of members are inserted in the mold partly formed into a basket with those fasteners joining the lips and ends which are in regions of the lips and ends which are relatively inaccessible within the mold and the remainder of the fasteners are secured and the basket is completed while the partly formed basket is within the mold.