US3467284A - Distributor for continuous casting machine - Google Patents

Description

Sept. 16, 1969 D. M. KONCSICS ETAL 3,467,284

DISTRIBUTOR FOR CONTINUOUS CASTING MACHINE Filed May 24, 1967 lull United States Patent 3,467,284 DISTRIBUTOR FOR CONTINUOUS CASTING MACHINE David M. Koncsics, Allentown, and Bruce C. Whitmore,

Bethlehem, Pa., assignors to Bethlehem Steel Corporation, a corporation of Delaware Filed May 24, 1967, Ser. No. 640,899 Int. Cl. B67d /64 US. Cl. 222166 2 Claims ABSTRACT OF THE DISCLOSURE A distributor for introducing molten metal into a continuous casting machine. The molten metal after being allowed to flow through two interconnected metal holding compartments, one below the other, is introduced into the continuous casting machine through a series of substantially V-shaped channels or weirs.

BACKGROUND OF THE INVENTION The invention relates to apparatus for the continuous casting of metals and more particularly to a distributor for introducing the molten metal into a continuous casting machine. It is especially suitable for use with continuous casting machines in which the metal is cast into a slab between a pair of moving endless belts, such as shown in US. Patent No. 3,03 6,348 to Hazelett et al.

It has long been recognized that in order to continuously cast a uniform product, the molten metal should be introduced into the continuous casting machine at a uniform rate. Previous distributors have used stopper rods, gate valves, float valves, pumps, siphons, tubes and other devices in an attempt to control the flow of molten metal into the continuous casting machine. In practice, such devices have frequently caused the flow rate to vary during the cast due to clogging, wear or being subject to a varying head of metal in the distributor. Furthermore, many of the known devices are only suitable for relatively low flow rates thereby limiting the casting or production rate of the continuous casting machine.

A number of the known distributors depend on the altertness and skill of an operator to maintain a uniform flow rate.

Many of the known distributors make no provision for treating or otherwise conditioning the molten metal immediately prior to its introduction into the casting machine.

It has also been observed that known distributors frequently do not permit rapid, precise adjustment of the metal stream relative to the casting machine nor do they make provisions for a quick positive interruption of the stream in the event of an emergency or at the end of the cast.

SUMMARY OF THE INVENTION It is therefore an object of this invention top rovide a distributor for introducing molten metal into a continuous casting machine at a rapid but substantially uniform rate.

It is a further object of this invention to provide a distributor which does not rely upon the alertness and skill of an operator, permits conditioning of the molten metal immediately prior to its introduction into the casting machine and provides precise, positive control of the metal stream.

Other and further objects of this invention will become apparent from the following description and the accompanying drawings and claims.

It has been discovered that the foregoing objects can be attained by a distributor mounted on a tiltable carriage 3,467,284 Patented Sept. 16, 1969 and comprising two interconnected covered metal holding compartments, one below the other and joined by an upstoppered metering nozzle, and having a plurality of substantially V-shaped channels or weirs through which the metal flows from the lower compartment into the continuous machine as a freely falling stream.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the figures and in particular to FIGURE 1, the distributor 1 is shown in conjunction with a conventional internal stopper ladle 2 and a continuous casting machine 3 of the type wherein metal is cast into a slab or billet 4 between a pair of water-cooled, moving endless belts 5. The distributor 1 is also suitable and easily adapted to other well-known types of continuous casting machines such as the type which utilizes a rectangular, open-ended, water-cooled mold.

The distributor 1 comprises two molten metal holding compartments, a tundish 6 and a Weir box 7 both constructed of steel plate lined with a suitable refractory. As shown in FIGURE 1, the tundish 6 has a separate refractory lined steel lid 8 provided with a teeming port or orifice 9 for the introduction of molten metal from ladle 2. The interior of tundish 6 is lined with refractory so as to provide a shallow portion 11 immediately under the teeming port 9 and a deeper portion or well 12. A perforated ring-like conduit 13 connected to a source of non-oxidizing gas under pressure, is embedded in the refractory lining of the lid 8.

The tundish 6 is supported by trunnions 14 on a pair of arms 15 which are free to pivot about points 20 of a carriage 16. The carriage 16 runs on tracks 17 in the floor of the pouring platform 18 immediately adjacent to the continuous casting machine 3.

The weir box 7 is provided with a cover 10 which is attached to the bottom of the tundish 6 so that weir box 7 is suspended from the bottom of tundish 6 as shown in FIGURE 1. An unstoppered refractory metering nozzle 19 having an unrestricted orifice connects the bottom of the well 12 of tundish 6 with the interior of weir box 7. The orifice is of a predetermined size to permit the metal to flow into weir box 7 at a substantially uniform given rate of flow.

The Weir box '7 has a shallow well 21 immediately under nozzle 19. A plurality of substantially V-shaped channels or weirs 22 extend from the well 21 towards the continuous casting machine 3 and terminate in a lip 23. As shown in FIGURES 1, 2 and 3, the cover 10 extends over most of the length of the weirs 22.

A refractory barrier or slag dam 24 propects towardly from the cover 10 of weir box 7 at the entrance to the weirs 22. A perforated, ring-like conduit 25 connected to a source of non-oxidizing gas under pressure, is embedded in the refractory lining of cover 10 of weir box 7.

An open refractory lined steel box 26 is mounted on the base of carriage 16 below and slightly to the rear of weir box 7. A hydraulic jack or similar lifting device 27 supports arm 15 in a substantially horizontal position when casting. A counterweight 28 is positioned at the rear of the carriage 16 to stabilize the carriage whenever the distributor 1 is full of molten metal.

Both the lid 8 of the tundish 6 and the rear wall of weir box 7 are equipped with ports 9 and 29 into which removable burners (not shown) are placed to preheat the refractory linings and weirs 22 of the distributor 1 prior to casting.

Prior to casting, the distributor 1 is preheated to a proper temperature by removable burners (not shown) inserted into ports 9 and 29 of the tundish 6 and weir box 7. The hot gases are exhausted through weirs 22 thereby also preheating the discharge portion of the distributor 1 to a suitable temperature. Immediately prior to casting, the burners are shut off and removed from ports 9 and 29 and the distributor 1 and carriage 16 are positioned immediately adjacent the continuous casting machine 3 as shown in FIGURE 1.

Molten metal from a melting furnace is brought to the pouring platform 18 in a conventional internal stopper ladle 2 by a crane. The molten metal is introduced into the tundish 6 from the ladle 2 through the teeming port 9 in the lid 8 and fills the tundish 6 to the level shown. Molten metal is added to tundish 6 from ladle 2 as required, in order to keep the level of the molten metal in the tundish well 12 substantially constant.

The molten metal fiows freely and unrestrictedly through the orifice of metering nozzle 19 filling the well 21 of weir box 7 to the level shown in FIGURE 1. This sized but otherwise unrestricted, unstoppered metering nozzle 19 eliminates the need for any stopper or valves between the tundish 6 and the weir box 7 which might require the services of an operator and which frequently have a tendency to clog or erode and thereby alter the flow of molten metal being delivered to the continuous casting machine 3. The molten metal flows from well 21 under slag dam 24 and through weirs 22 until it is finally discharged over lip 23 into the continuous casting machine 3 as a freely falling stream. Once the casting has commenced, a shallow pool of molten metal is maintained between the moving belts as shown in FIGURE 1.

If desired, gas may be injected into the tundish 6 and the weir box 7 above the surface of the molten metal through the perforated, ring-like conduits 13 and .25 as a means, depending on the nature of the gas selected, to either prevent oxidation of the molten metal or to further treat or condition the molten metal immediately prior to casting. Likewise, alloys or other solid additives may be added to the molten metal in the distributor 1 through ports 9 and 29 or ports specially designed for this purpose.

At the conclusion of the cast, ladle 2 is removed and jacking device 27 is lowered, permitting the arms to pivot about points and thereby tilting the entire distributor 1 downwardly and rearwardly. This immediately stops any further flow of molten metal over lip 23 of the weirs 22 and into the continuous casting machine 3. The molten metal and slag remaining in the tundish 6 and weir box 7 drain out the rear of distributor 1 into the open box 26 through port 29. As a result very little skull remains in the distributor 1 at the conclusion of the cast.

The channels or weirs 22 preferably have a cross sectional shape in which the sidewalls downwardly converge toward each other, preferably in the form of a V with the roots of all the V-shaped weirs 22 lying in a horizontal plane during casting..FIGURES 2 and 3 illustrate three such weirs 22 being used with the outer two weirs diverging slightly away from the center weir. A greater or lesser number of such weirs 22 may be used depending on the size of the product being cast.

A substantially V-shaped weir 22 is preferred since for a given head of metal in well 21 back of the weirs, one can obtain a relatively high velocity stream of molten metal. This high velocity plus the fact that the roots of the V-shaped weirs all lie in a horizontal plane, insures that the freely falling stream, after passing over lip 23, will project as far back into the area between belts 5 of the casting machine 3 as possible. Not only does this practice prevent possible damage to the belts 5 but it also permits the same distributor to be used for the casting of a variety of different sized products. Furthermore, the V-shape weirs, because of their inherent high fiow rate to exposed surface area ratio, reduces heat losses from the molten metal to a minimum.

We claim:

1. Apparatus for introducing molten metal into a continuous casting machine comprising a covered refractory lined tundish and a covered refractory lined weir box attached to and positioned beneath the bottom of said tundish, wherein the improvement comprises a stopperfree metering nozzle having a vertically aligned orifice connecting the interior of said tundish to the interior of said weir box and a plurality of channel-like weirs having downwardly converging sidewalls for delivering molten metal from the weir box to the continuous casting machine as a freely falling stream.

2. Apparatus for introducing molten metal into a continuous casting machine as a freely falling stream comprising a covered refractory lined tundish, a covered refractory lined weir box attached to and positioned beneath the bottom of said tundish wherein the improvement comprises a stopper-free metering nozzle having a vertically aligned orifice connecting the interior of said tundish to the interior of said weir box and a plurality of substantially V-shaped channel-like weirs, and adjustable means for positioning the roots of said V-shaped weirs in a common horizontal plane.

References Cited UNITED STATES PATENTS 1,690,749 11/1928 Moyer 164259 2,329,049 9/1943 Hulme 222-152 2,571,033 10/ 1951 Harter et al. 222166 3,036,348 5/1962 Hazelett et al. 164-278 3,080,627 3/1963 Hoteko 164278 X 3,221,379 12/1965 Shearman 222-164 3,315,323 4/1967 Speith et al 164-82 FOREIGN PATENTS 3,841 1886 Great Britain. 750,647 6/1956 Great Britain.

ROBERT B. REEVES, Primary Examiner

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