US3703204A

US3703204A - Integrated in-line method of continuously casting metal

Info

Publication number: US3703204A
Application number: US84341A
Authority: US
Inventors: David W Brownstein
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-10-27
Filing date: 1970-10-27
Publication date: 1972-11-21
Anticipated expiration: 1989-11-21

Abstract

Direct casting of molten metal such as steel is accomplished by forming a trough-shaped mold or mold liner of ablative material and by advancing it forwardly past a molten metal feed station and along a casting line. The shaped material is charred with the molten metal and is employed in its charred condition as an immediate trough shaped mold or mold surface for the molten metal being cast. External means is employed for supporting the charred mold-shaped ablative and advancing it horizontally forwardly with the metal being cast therein.

Description

United States Patent Brownstein [54] INTEGRATED IN-LINE METHOD OF CONTINUOUSLY CASTING METAL [72] Inventor: David W. Brownstein, 5437 E11- sworth Avenue, Pittsburgh, Pa. 15232 [22] Filed: Oct.27, 1970 21 Appl. No.: 84,341

[52] U.S. Cl ..164/87, 164/278 [51] Int. Cl. ..B22d 11/06 [58] Field of Search ..164/87, 276, 278, 281, 86; 65/100 [56] References Cited UNITED STATES PATENTS 3,110,941 11/1963 Fagg ..164/278 3,284,859 11/1966 Conlon et al. ..164/276 X 3,343,590 9/1967 Radd ..164/87 [451 Nov. 21, 1972 Radd ..164/87 Rochester et al 1 64/73 Primary Examiner-R. Spencer Annear Attorney-Green, McCallister & Miller [5 7] ABSTRACT Direct casting of molten metal such as steel isaccomplished by forming a trough-shaped mold or mold liner of ablative material and by advancing it forwardly past a molten metal feed station and along a casting-line. The shaped material is charred with the molten metal and is employed in its charred condition asan immediate trough shaped mold or mold surface for the molten metal being cast. External means is employed for supporting the charred mold-shaped ablative and advancing it horizontally forwardly with the metal being cast therein.

12 Claims, 14 Drawing Figures PATENTEDNBVZI I912 3703.204.

SHEET 2 BF 3 INVENTOR. David W Brownsfein 69am H/S ATTORNEYS 7 PA'TENIED um 21 I972 3. 7 O3 2 O4 sum 3 [1F 3 Fig. '.9

rlllllillll'l'llll'l'lliiiz l INVENTOR. David W Brownsfem BY we am. 021% HIS ATTORNEYS.

BACKGROUND OF THE INVENTION 1. Field of Invention This invention relates to the continuous metal casting art and particularly, to improved apparatus and procedure for horizontally continuously casting molten metal. A phase of the invention deals with the use of a charable ablative type of mold means for receiving, retaining and advancing molten metal from a feed or pouring station to and along a solidifying and castin line.

2. Description of the Prior Art The metal industry and particularly the steel industry has adopted continuous vertical casting procedure in larger mills for directly casting slabs, blooms and billets. However, such procedure requires an excessive overhead space in the mill and has tended to produce castings that are porous and have somewhat spongy interiors. Such physicals require additional reheating and rolling with a full complement of rolling equipment to improve the structure of the metal. So far as known to date, attempts to successfully employ production methods in accomplishing a continuous horizontal casting have not met with success, particularly due to the poor quality of the casting arising from contamination and unevenness of the cooling. Water spraying has been used for cooling the metal. It has also been necessary to contend with the problem of employing a segmented or sectioned type of mold means in order that a continuous forward movement may be accomplished and the molds returned for reusage.

SUMMARY OF THE INVENTION The present invention eliminates difficulties heretofore encountered with the continuous use of mold means from the standpoint of high temperature damage thereto, sticking of the cast metal therewith, and the presence of voids or overlaps between mold sections. It represents an entirely different approach in solving the problem presented and makes practical an efficient, low cost, continuous horizontal casting procedure that can be economically, flexibly utilized by a small mill to directly process molten metal. Molten metal produced by any conventional method may be used, whether by electric furnace melting, open hearth melting or oxygen blow melting. It does not require several hundred feet or more of overhead working space in the plant or mill.

At the present time, there are more than thirty small continuous vertical casting plants in the United States with capacities ranging from 50,000 to 400,000 tons per year. Such installations with necessary rolling equipment necessitate a capital expenditure in the neighborhood from 5 million or 6 million up to million dollars or more. In accordance with the present invention, equipment requirements can be met at about one half the above-mentioned minimum cost, and the finished product may be attained much quicker'with improved physicals. Segregation and porosity are minimized, and further rolling will be primarily effected for the purpose of producing different sections or sizes of the finished product. In other words, the need for extensive rolling to reduce porosity, etc. is

eliminated. The cast section can now be made relative- 1y thin as well as thicker, much closer to a desired finished size to substantially reduce rolling time. For example, a steel plate of 1 inch thickness by 86 inches in width may be produced for direct introduction into a regular strip mill to provide strip at the rate of tons per hour or more, eliminating the many roll passes heretofore required.

In accordance with the present invention therefore, a

so-called ablative strip of a suitable material, such as papier-mache, is continuously fed forwardly towards a. feed station while being shaped into a trough-like section. The ablative material as formed into a troughshape is employed as a mold and molten metal is introduced therein producing a charred, protective, insulating layer primarily for base and side faces or walls of the casting. Also, a solidified skin is formed along the- BRIEF DESCRIPTION OF THE DRAWINGS In the drawings,

FIG. 1 is a longitudinal top plan view of a metal casting system or apparatus arrangement constructed and employed in accordance with the invention.

FIG. 2 is a side view in elevation of the system or apparatus of FIG. 1, but additionally showing alternate usage of means for spraying-on ablative material.

FIGS. 3, 4, and 5 are enlarged transverse vertical sections taken respectively along the lines IHIII,-IVIV and V-V of FIG. 1.

FIG. 5A is a somewhat fragmental vertical section on the scale of and taken along the same line as FIG. 5 to illustrate a modified construction. .1

FIG. 6 is a longitudinal view in elevation similar to and on the scale of FIG. 2, but illustrating a modified system or apparatus arrangement employing the invention.

FIG. 7 is a longitudinal view in elevation on the scale of FIG. 6, but illustrating a further embodiment of the invention.

FIG. 8 is a transverse section in elevation on the scale of FIG. 5 and taken along the lines VIIIVIII of FIG. 1.

FIG. 9 is a transverse section in elevation on the scale of FIG. 8 and taken along the line IXIX of FIG. 1.

FIG. 10 is a fragmental transverse section on the scale of FIG. 9 and taken along the line XX of FIG. 2.

FIG. 11 is a transverse section in elevation on the scale of FIG. 10 and taken along the line XI-XI of FIG. 6.

FIG. 12 is a side fragmental section in elevation on the scale of and taken along the line XII, and

FIG. 13 is a transverse section view in elevation on the scale of and taken along the line XIII-XIII of FIG. 7.

' DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring particularly to FIGS. 1 and 2, a continuous, horizontally extending metal casting line or system is shown in accordance with which a continuous strip or length of an ablative material such as papiermache of a suitable thickness of, for example, onefourth inch is supplied from-a reel or roll A to the pass of a pair of motor-driven feed rolls B and upon the upper face of a continuously forwardly advancing upper reach of a heat resistant continuous belt 11 of a conveyor system C. The belt 11 advances over a motor driven tail pulley 17. As shown in FIG. 1, the flat or planar ablative material 10 and belt 11 may have substantially the same transverse width and are advanced at the same rate progressively into and through shaping-guide passes D and D' having pairs of cooperating

troughing rolls

12, 13 and 12', 13'.

As illustrated in FIGS. 1 to 4, inclusive, the lower roll 13 and 13' of each set or pair D and D' has flanged sides to define a substantially spool-shape while the upper roll 12 and 12' is of cylindrical shape and is adapted to fit within the associated lower roll in a complementary manner to progressively fold the sides of the belt 11 and the strip material 10 upwardly. In this connection, as shown in FIG. 3, the first folding operation at station D isaccomplished by bevel-edges 12a of upper roll 12 which cooperate with upwardly outwardly sloped or inclined faces 13a of flanged end portions of the lower roller 13. FIG. 4 shows the construction of cooperating upper and lower rolls 12' and 13' for completing the formation of an upwardly open, hollow or cavity forming, substantially trough-like assembly of substantially rectangular or channel-shaped section of the ablative strip 10 and the conveyor belt 1 1'. In this connection, the upper roller 12' has. rounded convex side edges 12b which cooperate with complementary, rounded concave portions 13b of the lower roll 13' and with adjacent side faces of both rolls 12' and 13' to form the trough shape that is attained before the assembly reaches a starting position as represented by a molten metal feed station, see tundish or molten metal distribution part F. At this time, molten metal may be continuously fed from'an overhead-positioned or suspended means, such as a ladle G whose outflow or feed is controlled by a conventional refractory stopper I5.

Molten metal introduced through a top opening in the tundish F flows forwardly outwardly centrally therefrom into the shaped ablative material or strip 10 as it advances forwardly thereunder to thus fill its open trough-shaped mold section. The material of the belt 11 will be of a suitable heat-resistant type, such as a flexible graphite woven fiber belt, produced and sold by BF. Goodrich Company whichwill withstand temperatures upward of 5,000 F. The thickness of the metal casting may be maintained at any desired value, as controlled by the stopper 15 and influenced also by the speed of forward movement of the mold assembly represented by the members 10 and 11.

When the molten metal from the ladle G and the tundish F flows directly into the upwardly open hollow section of the channel-shaped ablative material 10, it immediately causes the material to burn or char to thus form a somewhat hard protective coating along the base and opposed sides of the molten metal piece or member which is to be formed. This causes a cooling action on the immediately abutting surfaces of the metal to produce a substantially solidified surface film' or skin, but leaves the upper surface of the mold metal 14 .exposed to the ambient atmosphere. As the metal 14 is advanced with the mold body of the charred ablative I material, it progresses from molten through plasticand solidification zones. During the first stages of movement, there is an upward release of gases and other contaminants from the upper surface of the metal length 14. This has been found, with the production of the bottom and side skins to produce a good, solid, non-porous, dense cast metal structure. 7

The speed of the movement can be controlled to maintain substantially the same plastic and solidification zones for casting metal members of different widths, shapes and thicknesses. For example, using a length of stationary slide bedor table E of about thirty feet and a forward speed of about feet per minute, a good cast metal product having a width of 2 inches and a height of 1 to 1% inches can be produced employing a thickness of papier-mache from the roll A of about one-fourth inch; Although the charred strip 10 is hard and somewhat brittle, it is fully retained as a unitary, continuously moving protective mold channel along the full extent of the bed E. It will be noted that a woven graphite belt 11, such as above-mentioned, will provide the necessary strength in its supported relation with respect to the strip 10. Such belts can be provided 7 having strengths of up to 100,000 p.s.i. or more.

may be applied thereto. The trough-shape of the mold structure that is provided lends itself to the use of a slag blanket, with the slag being preferably supplied by a separate source to the tundish F.

In FIG. 2, a modified arrangement is illustrated, see also FIG. 10, in accordance with which a spray unit P is employed for applying ablative material, either as a coating to the surface of the belt material 11, but preferably as an ablative coating to a thin thickness of strip 10. The full lines of FIG. 2" show the feed of the: strip 10 from supply roll or reel A when it isbeing initially used, while the dotted lines show the relationship when the supply of the strip material is nearing exhaustion on the reel.

After the casting and the contoured mold reach the end of the slider bed E, they are shown passing over a tracking roller I of the general construction or shape of the lower roll 13' of roll pass D' of FIG. 4 which in cooperation with the rolls of station D', thru FIG. 4 which in cooperation with the rolls of station D'inclusive avoids any stress or strain on the charred ablative material 10. That, as shown, is the charred ablative mold maintains its unitary, substantially constant or uniform cross-sectional trough-shape during its movement along the full length of the table E. However, when the ablative strip material 10 reaches station J, it is broken up by suitable means, for example, by the flattening of the belt 11 on head pulley 16 of the conveyor C (see FIG. 9). If desired, a brush (not shown) may be located adjacent station I to further the removal of ablative material char 10'. As the belt 11 advances over its head pulley 16, it carries the brokenup ablative material and drops it into a collector or trap bin K to which negative air pressure may be applied to facilitate removal. At the same time, the solidified cast metal member or length 14 is being pushed forwardly upon a roll-out table L. The casting may then be sheared to any suitable length at station M (see FIG. 2) and then taken-off for usage or passed through a reheating furnace N and one or more hot roll stands 0.

The belt conveyor system C (see FIG. 2) in addition to having a motor-driven head pulley 16 is also shown provided with driven tail pulley 17, idler guide rollers or pulleys 18 and 18 and a tensioning of take-up roller or pulley 19. The under or return reaches of the continuous belt 11 are shown subjected to cooling air from air-applying blower means or duct heads H.

In the embodiment of the invention illustrated in FIGS. 6, 11 and 12, stationary table or slide bed E of FIG. 2 is eliminated and a bottom-positioned, continuous, fiat top chain conveyor system Q is provided. Pivotally connected, continuous chain sections 25 and endwise-abutting flat top metal plate elements 26 may be of a so-called steel flat top type, such as made and commercially sold by Link Belt Corporation, see its catalog No. 1050, page 156. However, unlike most commercial conveyors, its plates 26 will preferably have an endwise-abutting rather than a spaced relation with each other. Such a continuous chain conveyor is made up of flat-top, pivoted metal plate segments 26 to give it flexibility during its movement. The continuous belt system C of FIG. 6 is slightly modified with respect to the system C of FIG. 2, in that it has a second driven back-up roller or pulley 19 instead of a second idler pulley or roller 18'. Employing the system of FIG. 6 not only will the ablative material or strip 10 and the continuous supporting belt 11 be moved in synchronism (as in the embodiment of FIGS. 1 and 2), but the flat top chain conveyor Q will also be moved in synchronism therewith. Using such a flat top conveyor system Q, the metal of the chain construction serves as a better heat transfer conductor to the atmosphere than the slider bed E of the continuous belt system C. A bath type tank R containing a cooling medium such as air or a mist of an air and water is shown for cooling the belt 11 during its return movement along lower reaches of the conveyor C.

FIG. 5A illustrates the use of a flexible, metal-carrying and cavity-defining belt 21 that has been preformed with an open cavity shape or section. The pair of side guides 20 of the embodiment of FIG. 5A may thus beomitted. In this embodiment, the belt 21 will retain its formed shape throughout the operation, but will breakup the ablative material 10 at the head pulley 16 where it reverses its direction to move along its under or return flight beneath the stationary slide bed or table E. The belt, itself, may serve as an immediate ablative receiving agency for the molten metal where the operating temperature is relatively low and the belt has an inner face portion of an ablative type of material.

In the embodiment of FIGS. 7 and 13, the continuous belt C has been eliminated and the ablative strip 10 is carried directly by a cooperating group of two spacedapart side-positioned flat-top conveyors S and T and a bottom flat top conveyor Q. It will be noted that continuous flat top conveyors S and T are of the same general construction as Q. In this embodiment, the conveyors S and T take the place of fixed-positioned side guide members 20 (see FIG. 8) of the embodiment of FIGS. 1 and 2. The conveyors Q, S, and T are operated in synchronism to support and advance the charred ablative strip 10 and its metal member length 14. In the embodiment of FIGS. 6, l1 and 12 the side guide members 20 are carried on side-positioned stationaryframe structure, since the table E is eliminated and the section plates 26 are continuously moving forwardly.

In carrying out the process, the ablative 10 may be of various substances or materials. Although a paper type is preferred, it may be metallic or non-metallic pro-' vided it will char in a mold shape, lower the peak temperature of the metal being poured to form a protective skin therealong, and effectively reduce the molten metal deteriorating action on back-up cavity defining means, such as the continuous belt. For example, a paper with a range of about one thirty-second to onequarter of an inch in thickness or greater has been found to be satisfactory, with papier-mache being the optimum, although soft paper such as used for separating sheets and hard paper such as used for wrapping may also be employed. A plastic or resin, such as Teflon, that will char under the temperature of the molten material, having a thickness of up to about oneeighth of an inch may also be used. Representative metals, such as aluminum, lower temperature steel, tin and copper bearing alloys up to about one thirtysecond of an inch in thickness or thicker if of soft metal, may be used. Also, refractory metals such as zirconium and titanium oxides, graphite, charable petroleum products, aluminum or iron powder, may be applied as by a spray application to paper material.

In accordance with the invention, the operation is conducted in such a manner as to receive molten metal being fed or poured-downwardly into an open-top supporting cavity of continuous and unbroken extent, maintain the metal in a quiescent condition and advance it while solidifying it in such a condition along a horizontal, as distinguished from a vertical or inclined plane. It is important to not only provide an ablative for receiving and protecting the metal being poured, but also to limit the supporting mold engagement with the molten metal to three sides only, namely continuously along its bottom and opposed vertical sides, with its upper or top side out of contact with mold or forming means. A quiescent condition of the molten metal is provided during the teeming thereof; the operation also allows a maximum purging action of gaseous impurities, permits vacuum degassing and inert gas protection, and the use of a slag blanket along the upper or exposed side of the metal within the mold.

Heretofore, relatively poor control over metal solidification has been attained and, in this connection, quiescence of the metal has not been attained until the pouring of an ingot has stopped or the strand of a vertical casting has reached a remote distance from the tundish. The action of pouring molten metal, in itself, tends to set up and maintain agitation of the melt. It has been determined that a substantially immediate quiescence of the poured metal is a factor that must be and that is attained in carrying out the present process and that such condition is assured by the use of and the initial charring of the ablative, as furthered by the continuous, free and unbroken movement substantially horizontally endwise forward feeding of the molten metal along and in position within a substantially straight in-lines longitudinally continuous and transversely unbroken mold cavity. I have also discovered that the cooling rate of the metal can be influenced or controlled by modifying the physical or chemical characteristics of the ablative, and that the ablative material, such as paper, may be additionally treated with a wash such as a metal or a chemical wash, to the end of providing a suitable mold film, skin or coating or rate of formation thereof.

An ablative material as employed in accordance with the invention has reference to a material such as paper that, on being surface-abutted by the reception of molten metal being poured or introduced at the upstream end of a continuously forwardly moving mold, and on endeavoring to initially reach a temperature equilibrium with the contacting surfaces of the molten metal being received, will substantially immediately take-up heat from or cool and effectively remove superheat from contacting metal surfaces to form a solidified protective surface skin therealong. During the endeavor of the ablative material to reach a thermal equilibrium with the abutting metal surfaces, both are being advanced along the line and subjected to the cooling action of the ambient atmosphere as well as of the supporting structure of the conveyor. Also, as the ablative material reaches a kindling temperature in accordance with which it is charred, its oxidizing or burning action is slowed or restricted by the close abutting relationship of the metal skin. In any event, heat generated is insufticient or ineffective to again impart a superheat to the skin.

lclaim:

1. In an integrated substantially straight in-line method of continuously cast-forming molten metal along a substantially horizontal processing line into a longitudinally extending solidified metal member of improved characteristics, continuously advancing a length of ablative material forwardly along the line in the form of a substantially constant cross-sectional shape that defines a longitudinal cavity having metalreceiving bottom and opposed side walls therealong, flowing molten metal downwardly and then endwiseforwardly in a quiescent condition in the cavity at an upstream end of the line and supplying it as a continuous stream while progressively advancing the ablative material and substantially filling the cavity to form a continuous length of metal of a desired substantially uniform thickness forwardly along the cavity, at the place of introduction of the molten metal to thecavity removing heat from bottom and opposed side surface portions of the molten metal that are in abutting contact with the bottom and opposed side walls of the ablative material and progressively forming a solidified protective surface skin therealong and progressively charring abutting portions of the ablative material while the molten metal is being supplied, maintaining the metal length in substantially the same cross-sectional shape and supporting the metal length along its thus-formed protective skin while advancing the metal length along the line and purging gaseous impurities therefrom through an exposed upper surface portion thereof, and

while advancing and solidifying the molten metal along the line; and after the metal has been solidified, progressively removing the ablative material from its bottom and opposed side surface portions.

4. In a method as defined in claim 1, employing an ablative material selected from a group consisting of paper, papier-rnache, a resin, and a low temperature metal, all within a thickness range of about one thirtysecond to one-fourth of an inch.

5. In a method as defined in claim 1, employing paper material for the ablative, and preliminarily applying a material selected from the group consisting of zirconium, titanium oxide, graphite, charrable petroleum products, aluminum and iron powders as a spray application to the paper material before introducing the molten metal thereto. 6. In a method as defined in claim 1, feeding the molten metal downwardly in a controlled manner from an overhead-positioned ladle into a cross-extending tundish, then feeding the molten metal endwise-forwardly from the tundish into the cavity of the ablative material from a position in close adjacency with respect thereto, all while progressively advancing the ablative material along the line.

7. In a method as defined in claim 6, advancing the ablative material and the metal being poured forwardly on and in synchronism with and without relative movement with respect to a forwardly advancing continuous supporting conveyor. v

8. In a method as defined in claim 7, removing the ablative material from the cast metal length at a forward end of the line at which the conveyor is starting a return movement along the line.

9. In a method as defined in claim 1, first flowing the molten metal downwardly to a position substantially immediately above the cavity, and thereafter forwardly flowing the molten metal in a direct path substantially endwise into the cavity of the ablative material.

10. In a method as defined in claim 1, advancing th length of ablative material as a continuous strip from a backwardly positioned supply station along the line, forming the strip with a cavity of the defined cross-sectional shape forwardly of the supply station, retaining the ablativein its defined shape while advancing it to a feed station at which the molten metal is introduced into the cavity, thereafter maintaining the length of metal along the line in the defined cross-sectional shape and until the metal reaches a forward station at which it has become fully solidified.

11. In a method as defined in claim 10, at the feed station first flowing the molten metal into a cross-extending tundish and thereafter flowing it forwardly on a substantially horizontal plane endwise into the cavity of the ablative material and to a depth sufficient to subreaches support and advance the ablative material and the metal, moving the conveyor in a return path along its lower reaches backwardly along the line, and progressively scraping-off charred ablative material from the solidified metal at a forward position along the line where the conveyor is moving from its upper reaches towards its lower reaches.

Claims

1. In an integrated substantially straight in-line method of continuously cast-forming molten metal along a substantially horizontal processing line into a longitudinally extending solidified metal member of improved characteristics, continuously advancing a length of ablative material forwardly along the line in the form of a substantially constant cross-sectional shape that defines a longitudinal cavity having metal-receiving bottom and opposed side walls therealong, flowing molten metal downwardly and then endwise-forwardly in a quiescent condition in the cavity at an upstream end of the line and supplying it as a continuous stream while progressively advancing the ablative material and substantially filling the cavity to form a continuous length of metal of a desired substantially uniform thickness forwardly along the cavity, at the pLace of introduction of the molten metal to the cavity removing heat from bottom and opposed side surface portions of the molten metal that are in abutting contact with the bottom and opposed side walls of the ablative material and progressively forming a solidified protective surface skin therealong and progressively charring abutting portions of the ablative material while the molten metal is being supplied, maintaining the metal length in substantially the same cross-sectional shape and supporting the metal length along its thus-formed protective skin while advancing the metal length along the line and purging gaseous impurities therefrom through an exposed upper surface portion thereof, and progressively solidifying the metal length within the skin during its advancing movement along the line without inducing relative movement of the molten metal with respect to the ablative material.

2. In a method as defined in claim 1, employing paper as the ablative material and within a thickness range of about one thirty-second to one-fourth of an inch.

3. In a method as defined in claim 1, supporting the ablative material in its defined constant cross-sectional shape while introducing the molten metal thereto and while advancing and solidifying the molten metal along the line; and after the metal has been solidified, progressively removing the ablative material from its bottom and opposed side surface portions.

4. In a method as defined in claim 1, employing an ablative material selected from a group consisting of paper, papier-mache, a resin, and a low temperature metal, all within a thickness range of about one thirty-second to one-fourth of an inch.

5. In a method as defined in claim 1, employing paper material for the ablative, and preliminarily applying a material selected from the group consisting of zirconium, titanium oxide, graphite, charrable petroleum products, aluminum and iron powders as a spray application to the paper material before introducing the molten metal thereto.

6. In a method as defined in claim 1, feeding the molten metal downwardly in a controlled manner from an overhead-positioned ladle into a cross-extending tundish, then feeding the molten metal endwise-forwardly from the tundish into the cavity of the ablative material from a position in close adjacency with respect thereto, all while progressively advancing the ablative material along the line.

7. In a method as defined in claim 6, advancing the ablative material and the metal being poured forwardly on and in synchronism with and without relative movement with respect to a forwardly advancing continuous supporting conveyor.

10. In a method as defined in claim 1, advancing the length of ablative material as a continuous strip from a backwardly positioned supply station along the line, forming the strip with a cavity of the defined cross-sectional shape forwardly of the supply station, retaining the ablative in its defined shape while advancing it to a feed station at which the molten metal is introduced into the cavity, thereafter maintaining the length of metal along the line in the defined cross-sectional shape and until the metal reaches a forward station at which it has become fully solidified.

11. In a method as defined in claim 10, at the feed station first flowing the molten metal into a cross-extending tundish and thereafter flowing it forwardly on a substantially horizontal plane endwise into the cavity of the ablative material and to a depth sufficient to substantially fill the cross-sectional area of the cavity anD provide a continuous length of the molten metal along the cavity while advancing the ablative material forwardly along the line, and progressively cooling the molten metal as it is advanced along the line and while its upper surface is exposed to the ambient atmosphere.