US2951271A

US2951271A - Metal feed structure for continuous casting apparatus

Info

Publication number: US2951271A
Application number: US763931A
Authority: US
Inventors: Alfred H Tessmann
Original assignee: Ind Res And Dev Corp
Current assignee: Industrial Research and Development Corp
Priority date: 1958-09-29
Filing date: 1958-09-29
Publication date: 1960-09-06
Anticipated expiration: 1977-09-06

Description

Sept. 6, 1960 A. H. TESSMANN 2,951,271

METAL FEED STRUCTURE FOR CONTINUOUS CASTING APPARATUS Filed Sept. 29. 1958 Fa .l

VACUUM WATER OIL INVENTOR. AlFred H. Tessma nn BY I wu adhua 7 M 9 A Alf orneqs United States PatentO METAL FEED STRUCTURE FOR CONTINUOUS CASTING APPARATUS Filed Sept. 29, 1958, Ser. No. 763,931

2 Claims. (Cl. 22-57.2)

This invention relates to metal feed structure for continuous casting apparatus and more particularly to such structure and apparatus in which atmosphere or lubricant, or both, enter the inlet end of a continuous casting mold adjacent a nozzle through which metal is fed to the mold.

The structure herein disclosed is related to, and constitutes an improvement of structure of the type shown and described in my United States Letters Patent No. 2,837,791, issued June 10, 1958, for Method and Apparatus For Continuous Casting.

In a structure and apparatus of the type herein disclosed, and in apparatus of the type shown in my afore mentioned patent, molten metal enters the cavity of a continuous casting mold through a nozzle which extends into the inlet end of the mold. In order to prevent sticking of the metal to the mold surface, to facilitate movement of the metal through the mold, and to improve the surface finish of the cast metal, a controlled amount of lubricant may be introduced at the inlet end of the inner mold surface, between the nozzle and mold surfaces, from whence it moves into and through the mold. Also, by reducing the atmospheric pressure at the outlet end of the mold, advantageous results are produced, which include the removal of gas and air from the mold cavity and the production of a flow of atmosphere through the mold from the inlet to the outlet end which removes heat from the, cast metal and aids the flow and distribution of lubricant along the mold surface.

'.To provide for even distribution of the flow of either lubricant or atmosphere around the periphery of the inner surface of the. mold, as it passes into the mold from around the nozzle, it is desirable to have the nozzle concentric with the inner surface of the mold, with flow space provided around the inner end of the nozzle for described which are resistant to wear, so that the desired spacing relationships are maintained over long periods of use.

These and other objects and features of this invention will become apparent from the following description when taken together with the accompanying drawings in which:

Fig. 1 is a fragmentary side elevational view of continuous casting apparatus of a type in which the metal feed structure of this application is adapted to use;

Fig. 2 is a fragmentary side sectional View illustrating the adaptation of a preferred embodiment of my metal feed structure to continuous casting apparatus of the type depicted in Fig. 1; and

Fig. 3 is a fragmentary end sectional view taken substantially at the position indicated by a line 3-3 and accompanying arrows in Fig. 2, and drawn to a larger scale than that used in Fig. 2.

Although not necessarily limited thereto, the illustrative embodiment of my invention which is shown in the accompanying drawings is depicted in an adaptation to continuous casting apparatus in which the casting mold is horizontally disposed. Considered generally, the illustrated continuous casting apparatus embodies a mold assembly 10 carried on

supports

12 and 13 from a base 14. The mold assembly includes a tubular horizontally disposed mold 15 having a mold cavity 16 open at its opposite ends, and is surrounded from end to end by a water jacket 17. Desirably, the mold is made of a highlyheat conductive metal, such as copper, and has the inner surface thereof coated with a wear resistant metal,

such as chromium, which latter metal is highly polished to provided a smooth surface. The water jacket 17 encloses the outer periphery of the mold and is spaced therefrom to provide for the circulation of a coolant, such as water,

over the outer surface of the mold during casting. Such the passage of lubricant tor atmosphere or both longitudinally into the mold.

.In horizontally disposed casting apparatus, such as that disclosed, gravitational forces are opposed to the desired concentric relationship between the nozzle and mold surfaces, and the spacing between the nozzle and mold surfaces must be sufiiciently close to prevent the flow of molten metal from within the mold to the space between the nozzle and mold. Such factors complicate the problem of accomplishing the desired concentric relationship, while providing for the uniform peripheral flow distribution of atmosphere or lubricant or both to the mold surface. s

It is thus an object of this invention to provide coacting parts in a nozzle and mold structure for continuous casting apparatus which effect and maintain substantial concentricity and closely spaced relationship between the end of the nozzle and the adjacent inner surface of the mold, while providing for substantial peripheral uniformity of flow of atmosphere or lubricant or both past the end of the nozzle and into the inlet end of the mold.

Another object of my invention is to provide coacting parts in a nozzle and mold structure of the type herein coolant enters the water jacket through a conduit 18, and may be drained from the bottom of the water jacket.

In the disclosed apparatus, provision is made for the reduction of air pressure at the outlet end of the mold. For this purpose, a jacket 19, having an opening therethrough for the movement of cast metal, such as. 20, is connected to pressure reducing apparatus, such as a vacuum pump, through a conduit 22. Water enters the jacket 19 through a conduit 23 to provide a seal, as well, as to afford direct cooling of the cast metal as it emerges from the mold.

Molten metal which is to be cast flows into the inlet end of the mold from an auxiliary reservoir 24 through a nozzle 25. The molten metal supply for the auxiliary reservoir 24 is provided by an adjacent holding furnace, from which the flow may be regulated either mechanically or manually to maintain a level in the auxiliary reservoir 24 which will keep the mold cavity 16 filled continuously during the operation of the apparatus. The auxiliary reservoir is movably supported adjacent the inlet end of the mold by supports, such as 26.

f In apparatus of the type illustrated, the metal must be cooled sufliciently during its progress through the casting mold that an outer solid metal shell will form which is at least sufficiently thick to retain any molten metal which may still remain at the core of the cast piece. In order to aid in the avoidance of adhesion or sticking of the metal being cast to the inner surface of the mold, a controlled amount of lubricant is introduced into the mold through a conduit 27 and a passage 28 in a flanged insert 29, which flanged insert surrounds a portion of the nozzle 25 at the inlet end of the mold. The reduction of the atmospheric Patented Sept. 6, 1960 in inducing a flow of the lubricant through the mold beof lubricant through the mold shall be as evenly dis tributed as possible over the periphery of the mold cavity. Thus, it is desirable that the nozzle 25 through which the molten metal flows to the mold shall not only be spaced from the mold to afford clearancefor' the passage of atmosphere and lubricant, but the spacing of the nozzle from the mold should be substantially uniform and should be maintained by means which affords space for the passage of the atmosphere and lubricant without causing uneven distribution of the flow peripherally of the nozzle.

In the disclosed structure, the nozzle 25, as shown in Fig. 2, has an opening 30 therethrough for the flow of molten metal to the mold cavity 16; A peripheral rim 32 at the end of the nozzle which is within the mold cavity is in closely spaced relationship to the inner surface of the mold and is substantially uniformly spaced from the mold surface or surfaces. That is, this rim portion of the nozzle is desirably spaced uniformly from the interior of the mold by an amount in the order of a few thousandths of an inch.

To provide support for the nozzle the mold which will maintain the desired uniform spacing of the inner end portion and rim 3-2 of the nozzle from the inner surface of the mold, I have provided a series of relatively narrow peripherally spaced elements in the nature of splines 33 on the outer surface of the nozzle. The splines extend axially of the nozzle and are narrower circum ferentially of the nozzle than the spaces which intervene therebetween. The outer peripheral surfaces of the splines 33 are accurately ground to fit snugly into a bore 34 in a sleeve portion 35 of theflanged insert 29, which sleeve portion is secured in the inlet end of the mold 15, in a recess 36, by means such as threads 37. The sleeve portion 35 of the insert 2-9 is concentric with the mold cavity and flush with the inner surface of the mold, as well as having a close fit with the outer surfaces of the splines 33. The flanged insert 29 is made of wear resistant metal and is preferably hardened after being machined, so that the accurate support of the nozzle will be maintained through long periods of use.

During use, the nozzle is inserted into the mold to an extent such that the rim 32 is spaced inwardly of the mold from the sleeve portion 35 of the insert, so that molten metal fed into the mold through the nozzle does not contact the metal of the sleeve portion 35. The diameter of the nozzle adjacent the rim 32 and between the splines 3-3 is smaller than the external diameter of the rim 32, and the splines 33 terminate at their inner ends in spaced relationship to the rim 32. A peripheral groove 38 is provided internally of the insert 29, which groove is in communication with the passage 28 for distribution of the lubricant from the passage peripherally of the nozzle. Also, a sealing ring 39 is mounted in a peripheral recess 40 in the outer end of the flanged insert 29' and held in place by a ring 42 secured to the end surf e f h i sort by fastening means such as screws 43. This ring minimizes the escape of lubricant at the inlet end of the mold, but does not prevent the movement of atmosphere into the mold as a result of the reduced atmospheric pressure at the outlet end of the mold. Also, a water seal is provided between themold 15, the flanged insert 29 and the water jacket 17 by a sealing ring 44- secured in place by a metal ring 45. I

With the disclosed structure, it may be understood that lubricant flowing into the mold cavity through the passage 28 and peripherally distributed through the groove 38 may readily pass longitudinally of the nozzle and into the mold cavity through the spaces between the splines 33. The spacing of the inner ends of the'splines from the rim 32 serves to reestablish the peripheral continuity of the lubricant flow resulting from the presence of the splines. Also, the difference in diameter between the rim 32 and the portion of the nozzle between the and the inner ends of the splines serves additionally to accomplish peripheral continuity and even distribution of the lubricant as it passes across the rim 32 and into the mold cavity. It is to be recalled, of course, that the reduced atmospheric pressure at the outlet end of the mold aids in the inducement of the flow of lubricant and atmosphere through the mold from the inlet to the'outlet end thereof.

Having thus described my invention, what I claim as" new and desire to secure by 'Letters Patent of 'the' United" States is: i

1. In metal feeding structure for continuous casting end thereof within the mold which projects radially out wardly from said outer surface and is in closely spaced relationship to the mold, and means including elements spaced peripherally of the nozzle within the mold and having surfaces peripheral to the nozzle whose sectional dimension is greater than that of said rim portion at the end of the nozzle, said elements being located longitudinally of the nozzle between said rim portion at the end of the nozzle and the inlet end of the mold and in spaced relationship to said rim portion for supporting the nozzle within the mold at a position in which said rim portion at the end of the nozzle is substantially uni-- formly spaced from the mold.

. 2. In metal feeding structure for continuous casting apparatus as defined in claim 1, the combination being further characterized by an insert secured in the inlet end of the mold at a position normally spaced toward the inlet end of the mold from said rim portion at .the end of the nozzle and having a surface substantiallyflush with the inner surface of the mold and engaging said elements to provide a bearing support therefor. I

References Cited in the file of this patent UNITEDSTATES PATENTS 2,187,720 Williams Jan. 23, 1940