US3451465A

US3451465A - Method and arrangement for introducing lubricating material into a stationary chill for continuous casting of metal

Info

Publication number: US3451465A
Application number: US566602A
Authority: US
Inventors: Guenther Moritz
Original assignee: Vereinigte Aluminium Werke AG
Current assignee: Vereinigte Aluminium Werke AG
Priority date: 1965-07-24
Filing date: 1966-07-20
Publication date: 1969-06-24
Anticipated expiration: 1986-06-24
Also published as: CH451416A; AT264739B; BE683753A; LU51619A1; NL6609859A; SE318371B; NO116685B; GB1144208A

Description

INVENTOR( Gum M k #d ff ker ATTORNEY m M //////////////H\\ June 4, 1969 G. MORITZ METHOD AND ARRANGEMENT FOR INTRODUCING LUBRICATING MATERIAL INTO A STATIONARY CHILL FOR CONTINUOUS CASTING OF METAL Filed July 20. l956 United States Patent O F Int. c. nz'zd 11/10 U.S. Cl. 164-268 6 Claims ABSTRACT OF THE DISCLOSURE An arrangement for lubricating a strand of molten metal during casting thereof in which lubricating material passes by capillary action through a porous member at the inlet opening of a chill heated by the molten metal continuously fed through the inlet opening so that the lubricating material will condense on the cooled passage surface of the chill and form a lubricating film between the metal moving through the passage and the surface of the latter.

The present invention relates to a method and arrangement for introducing lubricating material during continuous casting of metals in a stationary chill, in which the lubricating material is introduced through a porous Wall portion of the chill.

In known methods of this type the lubricating material is introduced through a wall portion of the chill in the region in which the molten metal enters the chill, which wall portion is in this region formed from porous material, as for instance graphite or sintered Copper. The introduction of the lubricating material in this case is performed by means of a pump which pumps the lubricating material through the noncooled porous wall portion of the chill into a passage through the latter through which the molten material passes to be cooled and solidified. The lubricating material in this known process is fed in substantally liquid form into the passage of the chill, whereby, when the amount of lubricating material introduced by the pump is not correctly adjusted or during operating troubles, not properly formed metal strands or even an interruption of the casting process may occur due to sudden evaporation of introduced excess lubricating material. In order to assure with this method a trouble-free operation of the chill the use of an expensive precision pump is necessary, and even with such a pump a trouble free operation will not be assured under all circumstances.

It is an object of the present invention to overcome these disadvantages of methods and arrangements known in the art for introducing lubricating material into a chill for continuous casting of metal.

With this object in View, the method according to the present invention, for introducing lubricating material into a cooled passage of a chill for continuous casting of metal, mainly comprises the steps of continuously feeding molten metal through an opening in a porous heat-resistant member having a cross section smaller than the cooled passage into the latter so that at the junction of said opening and the passage an annular space 'will be formed about the stream of molten metal entering the passage, providing a supply of substantially liquid lubricating material closely adjacent to the aforementioned space in contact with the porous member so that the lubricating material will be transferred by capillary 3,451,465 Patented June 24, 1969 action through a portion of the member into the aforementioned space and be evaporated therein, and continuously withdrawing the lubricating material from the aforementioned space by the stream of metal passing through the passage, whereby the lubricating material will condense on the cooled surface of the passage and form a film of lubricating material between the metal passing through the passage and the surface of the latter.

The arrangement for carrying out the aforementioned method mainly comprises a chill having wall means forming a passage therethrough and means for continuously cooling the wall means forming the passage. The passage has an inlet end of given cross section, and the arrangement includes further a member of porous heat-resistant material abutting against the Wall means of the chill in the region of the inlet end of the passage and being formed with an opening therethrough substantially aligned 'with the inlet end of the passage and having a cross section smaller than the latter, and means for continuously feeding molten metal through the opening in the member into the passage, whereby at the junction of the opening and the passage an annular space fre-e of metal will be formed. Channel means are formed in the wall means in the region of the inlet end of the aforementioned passage and closely adjacent to the aforementioned annular space, which passage means are open toward the porous member. 'Ihe channel means are filled with lubricating material, so that the lubricating material will pass by capillary action through the porous member into the forementioned space to be evaporated in the latter and to be taken along by the stream of metal passing through the passage to be condensed on the cooled surface of the passage so as to provide a lubricating film between the metal and the surface definng the passage.

A pump is not necessary in this arrangement and the transfer of the lubricating material from the aforementioned channel means into the passage through which the molten metal is introduced will be provided only by capillary action so that an overpressure in the aforementioned passage which could lead to a detachment of the metal strand from the wall of the chill forming the passage and thereby to a disturbance in the casting process, is postively avoided.

The novel features which are considered as characteristic for the invention are set forth in particular in the appende'd claims. The invention itself, however, both as to its Construction and its method of operation, together With additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. l is a partial cross sectional view of an arrangement 'for carrying out the process of the present invention in which the passage through the chill is horizontally arranged; and

FIG. 2 is a partial cross sectional view of a similar arrangement in which the passage through the chill is vertically arranged.

Refering now to the drawing, and more specifically to FIG. l of the same, it will be seen that the arrangement according to the present invention, comprises a mold or chill 1 formed with an elongated passage la therethrough, only partially shown in FIG. 1, which, in tlhe embodiment shown in FIG. l, extends in substantially horizontal direction. The 'Wall of the chill, and especially the passage la therethrough, is cooled by a water jacket 2, also only partly sho wn in FIG. 1, surrounding the passage la and through w hich cooling Water is circulated in a 'known manner. The inlet end, that is the right end of the passage la, as Viewed in FIG. 1, is closed by a plate 5 abutting against the right end 'wall of the chill 1 and formed -with an opening 4 therethrough having a cross section smaller than the cross section of the passage la and substantially aligned with the latter. Molten metal to be cast in the chill is continuously fed in a manner known per se [from a container 6 arranged to the right side of the plate 5, as viewed in `F IG. 1, so that the metal passes through the opening 4 in the plate into the passage la. As the molten metal enters the cooled passage la, it forms an outer shell 7 of solidified material and a liquid core 8 of molten metal, and the transverse cross section of the outer shell 7 increases while that of the core 8 decreases as the metal passes longitudinally through the passage la so that when the metal leaves the outlet end of the chill, not shown in the drawing, a substantially completely solidified strand of metal is produced which is continuously withdrawn from the chill by means not shown in the drawing. Due to the surface tension of the liquid metal and due to the fact that the cross section of the opening 4 in the plate is smaller than the cross section of the passage la, an outer space 9 free of metal will be formed at the junction of the opening 4 with the passage la, as shown in FIG. 1. Channel means 10 are formed spaced a few millimeters from the space 9 in the end wall of the chill against which the plate 5 abuts. The channel means 10 are open towards the plate 5 and supplied with lubricating material from a reservor of lubricating material, not shown in the drawing, by passages likewise not indicated in FIG. 1. The plate 5 is Lforrned from heat resistant porous material so that the lubricating material in the channel means 10 passes by capillary action into the plate 5 and also to a portion of the latter which borders the space 9. This portion of the plate 5 is heated by the hot liquid metal so that the lubricating material at the surface of this plate portion Will be evaporated. The evaporated lubricating material passes into the space 9 and condenses by contact with the cooled surface of the wall of the chill, The thus condensed lubricating material is taken along by the metal continuously passing through the passage la of the chill so as to form a lubricating film between the metal and the surface of the wall defining the passage la, while additional lubricating material is continuously fed through capillary action from the channel means 10 into the space 9.

The plate 5 is preferably divided into two sections Sa and 5b which are coextensive with each other and between which a foil 11, for instance of aluminum, which is imprevious to the lubricating material, is sandwiched so that the lubricating material is confined to the plate section Sa.

While FIG. 1 illustrates an arrangement for continuous casting of metal in horizontal direction, BIG. 2 illustrates an arrangement in which the metal is continuously cast in vertical `direction and in which the passage la' through the chill 1' extends therefore in vertically downward direction. The wall of the chill 1' -forming the passage la' therethrough is again cooled by an outer water jacket 2' and in the arrangement shown in F IG. 2 an annular member 5' of porous heat resistant material is arranged at the inlet or upper end of the passage 1' through which molten metal to be cast is continuously fed in a manner known per se into the passage la' of the chill. 'Ihe cross section of the opening defined by the annular member 5' is again slightly smaller than the cross section of the passage la' so that at the junction of the bottom end of the member 5' with the passage la' an annular space 9' free of metal will be formed for the reasons stated above. Channel means 10' are formed closely adjacent to the aforementioned space 9' in the inner wall of the chill 1' and the passage means 10' are filled with lubricating material in the manner as described above, which lubricating material will be transferred into the space 9' by capillary action through a portion o f the porous member 5' to form a lubricating film between the outer solidified portion 7' of the cast metal and the inner sur- .4 face of the wall of the chill defining the passage la' to facilitate downward movement of the solidified outer portion 7' of the metal, while the inner liquid core 8' of the same gradually solidifies during the passage through the elongated chill.

The plate 5 and the annular member 5' may be formed from Marinite.

The following materials may be used as lubricating material: Vegetable oils such as peanut oil.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of methods and arrangements for lubricating a strand of metal during continuous casting thereof in a chill difiering from the types described above.

While the invention has been illustrated and described as embodied in a method and arrangement for lubricating a strand of metal during continuous casting thereof in a stationary chill, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristcs of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be Secured by Letters Patent is:

1. An arrangement for lubricating a strand of metal during continuous casting thereof, comprising, in combination, a chill having wall means forming a passage through said chill and means for cooling the wall means forming the passage, said passage having an inlet end of a given cross section; a member of porous heat resistant material abutting against the wall means of said chill in the region of the inlet end of said passage and being formed with an opening therethrough substantially aligned with said inlet end of said passage and having a cross section smaller than the latter; means for continuously feeding molten metal through said opening in said member into said passage, whereby at the junction of said opening and said passage an annular space free of metal will be formed; channel means formed in said wall means in the region of said inlet end of said passage closely adjacent to said annular space, said channel means being open towards said porous member and closed toward said passage and being adapted to be filled with lubricating material, so that the lubricating material will pass by capillary action through said porous member into said space to be evaporated in the latter and to be taken along by the stream of metal passing through said passage to be condensed on the cooled surface of said passage so as to provide a lubricating film between the metal and the surface defining said passage.

2. An arrangement as set forth in claim 1, wherein said channel means extend about said inlet opening of said passage.

3. An arrangement as set forth in claim 1, wherein said passage extends in substantially horizontal direction from a substantially vertical end wall of the chill, and wherein said porous member comprises a plate of porous heatresistant material abutting against an outer face of said end wall and being formed with said opening therethrough, said channel means being formed in said end wall and being open towards said plate.

4. An arrangement as set forth in claim 3, wherein said plate has a pair of parallel coextensive plate sections, one of which abuts against said end wall, and a foil of material impervious to the lubricating material sandwiched between said plate sections and extencling over said channel means for preventing lubricating material to pass from 5 said one into the other of said pair of plate sections.

5. An arrangement as set forth in claim 4, wherein said foil is made from alumnum.

6. An arrangement as set forth in claim 1, whercin said passage means extends in substantially vertical direction, and wheren said member of porous heat resistant material is an annular member located at said inlet end of said passage, said channel means being formed in said wall means about the lower end of said annular member.

References Citeil UNITED STATES PATENTS 2,747,244 5/ 1956 Goss 164-268 3,381,741 5/1968 Gardner 164-283 2,690,600 10/ 1954 Tarmann et al. 164-268 10 J. SPENCER F OREIGN PATENTS 3/1962 France. 12/ 1953 Germany.

OVERHOLSER, P''nay Exam'ner.

R. S. ANNEAR, Assistant Examie'.

U.S. Cl. X.R.