US2276657A

US2276657A - Continuous casting process

Info

Publication number: US2276657A
Application number: US257222A
Authority: US
Inventors: Junghans Siegfried
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-02-18
Filing date: 1939-02-18
Publication date: 1942-03-17
Anticipated expiration: 1959-03-17

Description

March 17, 1942. s. JUNGHANS CONTINUOUS CASTING PROCESS Filed Feb. 18, 1939 W h u r Jw f. A da% .8 lh L Patented Mar. 17, 1942 CONTINUOUS CASTING PROCESS Siegfried Junghans, Stuttgart, Germany, assignor to Irving Rossi, New York, N. Y.

Application February 18, 1939, Serial No. 257,222 In Germany February 18, 1938 10 Claims.

The continuous casting processes which have been developed recently enable endless castings to be produced in one uninterrupted continuous operation, i. e. without interrupting the casting process. These castings may be in form of round rods or bars, squares, or plates of rectangular cross section. A proposal has also been made to produce similar hollow bodies by the continuous casting process.

It is the object of the present invention to produce such endless castings with varying cross sections in a continuous casting process, so-that one and the same endless casting possesses different cross sections at various points throughout its length. These changes in the cross section may be made according to requirements either abruptly so as to form sharp shoulders or the change may be gradualin the manner of a cone. Various practicable methods are required according to the variation in cross section it is desired to obtain and these methods will be described hereinafter.

The accompanying drawing illustrates by way of example suitable devices according to the invention in which:

Figure 1 illustrates the arrangement of several moulds for casting castings having stepped cylindrical cross sections,

Figure 2 illustrates another arrangement of the mould for obtaining castings according to the device illustrated in Figure 1,

Figure 3 illustrates an arrangement of the mould for casting endless conical castings,

Figure 4 illustrates an arrangement for producing castings according to Figure 3 as used in a continuous casting process, wherein the mould carries out a continuous up and down movement during the casting process.

Figure 5 illustrates an arrangement of the mould whereby two castings can be cast simultaneously, one surface of each casting extending parallel to the direction of feed thereof whilst the other surface is conical.

Figure 6 illustrates a mould arrangement according to Figure 5 for a casting process wherein themculd is continuously moved up and down during the casting process.

In all the figures a is the nozzle used in continuous casting processes for c nveying the molten mass into the mould. The end of this nozzle is designat d by b and it is intended that this end sheuld always be immersed in the liquid head of the casting being produced in the mould.

According to the device illustrated with reference to Figure 1, various moulds, c, d, e, j .are provided, these being arranged in the manner of telescopic tube at the beginning of the casting process. As will be seen the mould possesses a number of difi'erent cross sections, each individual section being arranged so that it may be separately removed in the downward direction. The arrangement may also however, be such that each section can be separately removed in the upward direction. The inlet and outlet pipes for conveying cooling medium to the mould are designated by g h, i, k. The upper ends of each section of the mould are internally bevelled, so that the transition from one cross section to the next cross section of the mould extends along the said bevelled edges.

The casting process by means of the arrangement according to Figure 1 is as follows:

At the beginning of the casting process the lower end I) of the filler nozzle a extends into the inner mould f a depth such that when the mould is filled and the casting plant has been adjusted to correct position said lower end I: is constantly located within the liquid head in the mould f. Any desired length of casting may then be cast by means of this mould j the setting metal being withdrawn in the downward direction as is known in continuous casting processes. When the desired length of casting having the cross section of the mould f has been cast, the mould is pulled downwardly while the casting process continues. During the withdrawal of the mould f, the liquid head, the height of which is preferably maintained at a constant level, gradually fills the bevelled portion of the mould ,f and when the latter has been completely removed the liquid head reaches'the wall of the mould e. The desired length of casting having the cross section of e is then cast in the cast in the mould c. When it is desired to proceed to the cross section d the mould e is pulled downwardly and the same procedure is followed as when proceeding from the mould f to the mould e. The procedure is the same when the casting is to be enlarged to the cross section of the mould c. and. so on, and finally a casting is produced having various cross sections f, e, d, a, each cross section extending over any desired length of the casting.

In this method of casting the nozzle a is constantly located with its end b at a fixed point. However, the method may also be such that in addition to the downward movement of the mould the nozzle is simultaneously moved in the opposite direction, i. e. upwardly, thus efiecting a more rapid transition from one cross section to liquid head. As soon as a suflicient length of casting'having the cross section f has been obtained, the nozzle is withdrawn upwardly until I it. is again just within the liquid head in the mould e after the mould f has been removed, for exampleto the point marked l. During the upward movement of the nozzle or alternatively when the latter has reached point I, the mould f is removed downwardly. As in the meantime the space corresponding to the bevelling has been filled with molten mass and this has solidified, the solidified end downwardly moving casting pushes the mould f in the downward direction as soon as the devices retaining said mould have been released. The same method is followed in the case of the moulds e, d and c, the nozzle being raised in the meantime first to point 2, then to point 3 and so on upwardly.

According to Figure 2 means are provided for casting a casting having various cross sections arranged in steps, consisting of one single mould the internal wall of which possesses the cross sections to be cast. The internal wall of the cooled mould c is divided into a number of cross sections dq. The height of each individual cross section is so proportioned as to always be slightly larger than the appertaining liquid head, so as to ensure satisfactory casting and solidifying.

The casting process according to this embodiment is as follows:

The nozzle a is located with its lower end b in the largest cross section at so that the nozzle end b is constantly located within the liquid head having the cross section d. The casting process is continued with this cross section until the desired length of casting has been reached. The end b of the nozzle a is then raised so far into the cross section e that it is located just within the liquid head in the latter cross section. Casting is then carried on in this cross section until the desired length of casting has been obtained, whereupon the end b of the nozzle is raised into the next cross section 1. The process is continued until casting has taken place in all the cross sections for the required lengths so that finally the end b of the nozzle (1 is located in the cross section q.

The same result can of course be obtained when the nozzle a is stationary and the mould c is moved downwardly according to the length required for each different cross section.

As a further alternative, both the nozzle and the mould may be moved simultaneously in opposite directions.

In the hereinbefore described devices illustrated in Figures 1 and 2, the transition from one cross section to another is efiected step by step at intervals and consequently a casting is produced having cross sections; which vary step by step.

The arrangement according to Figure 3 now proceeds from the step by step casting method to the casting of conical castings. Also in this case is the cooled mould, having internal surfaces tapering toward the top. The length of the wall of the mould and the conicity correspond to the ratio of length to the conicity of the casting s to be produced. The shape of the interior of the mould thus corresponds to a smaller scale of the shape of the casting to be produced. The casting process is as follows:

The nozzle :1 is at first located with its end b in the cylindrical or rectangular portion of the cross-section of the mould c. The mould is filled and the plant is set in motion as soon as the end b is within the liquid head in the cylindrical or rectangular portion. At the same time a mechanism is set-in motion for raising the nozzle upwardly at a pre-determined speed. The operator in attention must take care during the whole of the casting process to see that the end b of the nozzle remains at a constant level within the liquid head. The conical casting is thus automatically produced, the length and conicity of which depends upon the speed at which the nozzle is raised. The greater the speed the greater will be the conicity and the shorter will be the casting, and vice-versa.

It is understood that the upward movement of the nozzle can also be arrested for a certain period during the casting, so that during this period there will be produced a portion of casting which is not conical. As soon as the nozzle is again set in motion the shape of the casting will again be made conical. The same result can be obtained when the nozzle is stationary and the mould is moved or when both nozzle and mould are moved simultaneously. The movement of the mould and of the nozzle is best eflected automatically by the aid of well known mechanical means.

In these processes it is also possible to cast in the reversed sequence, for example in such a manner that when the nozzle a reaches its uppermost position the process can be continued by slowly moving the nozzle downwardly again. In this manner a casting is produced which is conically tapering towards both ends.

In many continuous casting processes the mould carries out in addition an up and down movement in order that a uniform structure may be obtained in the casting. For this purpose the arrangements according to Figures 1 and 2 but not the arrangement in Figure 3, are suitable. During this continuous up and down movement of the mould the infiowing liquid metal would flow between the solidified endless casting and the wall of the mould.

In such cases where a reciprocatory movement is required the casting process must be carried out with the aid of an arrangement according to Figure 4. The process itself is the same as in the case of the device according to Figure 3 with the exception that the interior wall of the mould c is so arranged that the necessary to and fro movement is not efiected in the direction indicated by the arrow :1: but in the direction of the arrow y. This to and fro movement is effected by means of plates arranged adjacent the wall of the mould.

By the aid of the device according to Figure 5 castings are produced which are vertical on one side and have a conical surface of the other side (with respect to the direction of feed of the endless castings). In this case two castings are produced simultaneously; a and a are the two nozzles havingthe lower ends I) and D The outer cooled mould having plane inner walls is designated by the letter 0 whilst d is the inner mould having the conical outer walls. e is the water inlet pipe for the inner mould d.

The casting process is the same aswith the device .in Figure 3. The outer ;muld can in this case be moved to and fro during the casting process whilst the inner mould must remain stationary. When however an up and down movement of the inner mould d is also required the outer walls of the said inner mould' (1 must be arranged so as to be movable in the direction of the arrow y as in the process according to Figure 4 and the device as in'Figure 6. The casting process is then carried out in the manner described with reference to the device according to Figure 3.

The processes described with reference to Figures 1 to 6 illustrate by way of example a few methods and means for obtaining in a continuous working operation castings having different cross sections.

It is of course possible to produce not only the cross sections illustrated in the drawing and described in the foregoing but also entirely different cross sections in one and the same casting, for example the casting may have a circular cross section which goes over into a rectangular or square or hexagonal cross section.

The methods and devices described are intended to show merely the principles on which various cross sections can be obtained in a continuous process in one and the same casting. The invention of course comprises all possible constructional forms which fall within the principles disclosed.

Having now particularly described andascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. A mold for continuous string casting, comprising an open ended casting mold having its inner. wall enclosing a hollow chamber decreasing materially in size from the bottom to the top, and a tube extending into the mold to convey the metal therein and being movable in the direction of the axis of the mold in relation to the mold.

2. A mold for continuous string casting, comprising an open ended casting mold having its inner wall enclosing the hollow chamber decreasing in size from the bottom to the top, a tube extending into the mold to convey the metal therein, and plates arranged adjacent the inner wall of the mold which are movable along the inner wall.

3. A method for casting continuously produced cast articles whose cross section at various planes of the article have different diameters, comprising applying a molten metal to an open-ended mold, the internal wall of which is formed as step like deposits whereby the step of larger diameter is arranged the lowest in the mold, maintaining the height of the upper surface of the cast metal constant in the mold during the casting of each particular diameter, and raising this upper surface step-wise when the diameter of the casting is to be altered.

4. A method of continuous string casting having varying cross sections at different places, comprising introducing a molten metal by means of a tube into an open-ended mold which at various planes along its height has various cross sections, which decrease from the bottomto the top, maintaining the height of the upper surface of the cast metal relative to the mold constant during the casting of each cross sectional configuration, casting the metal and changing the height of the upper surface of the metal relative to the mold as soon as one casting is to be cast into another cross section.

5. A method of continuous stringcasting having varying cross sections at different places, comprising introducing a molten metal by means of a tube into an open-ended mold which at various planes along its height has various cross sections, which decrease from the bottom to the top, and continuously changing, the height of the upper surface of the cast metal relative to the mold from the bottom to the top of each cross sectional configuration.

6. A method for casing continuously produced cast articles whose cross section at various planes of the article have different diameters, comprising applying a molten metal to an openended mold, the internal wall of which is formed as step like deposits whereby the step of larger diameter 'is arranged the lowest in the mold, maintaining the height of the upper surface of the cast metal constant in the mold during the casting of each particular diameter, and raising this upper surface continuously when the diameter of thecasting is to be altered.

7. A mould for continuous string casting, comprising an open ended casting mold having its inner wall shaped as stepped sections each of the sections having a materially larger diameter than the section above it, and a tube extending into the mold to convey the metal therein, and being movable in the direction of the axis of the mold in relation to the mold.

8. A mold for continuous string casting, comprising an open ended casting mold having its inner wall enclosing a hollow chamber decreasing materially in size from the bottom to the top, and a tube extending into the mold to convey the metal therein, said tube and mold being movable relative to each other.

9. A method according to claim 3, in which the rais'ng of the upper surface of the cast metal when the diameter of the casting is to be altered,

is carried out by increasing the flow of the molten metal above that which is required to produce the casting.

10. A method according to claim 4, in which lower outlet opening of the tube is maintained at a constant distance below the level of the upper surface of the cast metal.

TSIEGFRIED JUNGHANS.