JPS6130259A - Method and device for continuously casting metallic pipe andproduct thereof - Google Patents

Abstract

Dense, homogeneous tubular metal products (33) such as pipe is cast in long lengths continuously by introducing liquid metal (32) into the lower portion of an annular-shaped casting vessel (11). The liquid metal (32) is withdrawn in the presence of at least one elongated upwardly travelling alternating electromagnetic levitation field and a second inner electromagnetic containment field for maintaining the tubular liquid metal column (26) in a substantially weightless and pressureless condition while solidifying. The resulting solidified tubular metal product (33) is withdrawn from the upper portion of the field, cooled and further processed to result in a desired end product.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a new and improved method and apparatus for continuously manufacturing tubular metal products (e.g. pipes) and the products obtained thereby.

More specifically, the present invention provides a method for reducing gravity and friction acting on a molten tubular metal product while maintaining the highest degree of effective heat transfer between a heat exchanger and a tubular molten metal column forming the tubular metal product upon solidification. The present invention relates to the continuous production of long tubular metal products (e.g. pipes) by casting in the presence of a levitation electromagnetic field to minimize forces and adhesion.

Prior Art Tubular metal products such as pipes have traditionally been manufactured by various methods, including casting.
They are described in detail in the literature relevant to the art. For example, U.S. Patent N. dated June 23, 1981
The description of the prior art found in columns 1 and 2 of Memorandum No. 4274/1.70 contains a number of prior patents and technical papers describing electromagnetic casting apparatus suitable for manufacturing tubular metal products such as pipes. are enumerated and the drawbacks of these known conventional methods are devised. Examples of such prior patents include U.S. Pat. No. 3,467,166 to Q etselev et al.;
eV), US Pat. No. 3,605,865, Carlson (
Karlson, U.S. Pat. No. 3,735,799; Getselev, U.S. Pat. No. 4,014.
No. 379 and Getselev US Pat. No. 4,126,175, both of which describe the use of electromagnetic molds. Such an electric 1m type confines the molten metal pool moving downward within a specified size range, and plows the laterally expanding outer portion of the pool to solidify within it. In this size, the build-up of solidified metal occurs longitudinally and the molten metal is fed semi-continuously or continuously by gravity flow to the upper end of the descending pool forming the solidified ingot. One of the minor drawbacks of this method is the lack of the "fail-safe" characteristics of the previously known ascending casting technique.

Therefore, in the event of an unexpected power system failure, etc., molten metal can spill out of the downwardly moving molten metal pool, rather than simply flowing back as in ascending casting systems. be. On top of that,
Because of the potential for molten metal overflow and escape in these known downward casting techniques, it is necessary to constantly and closely control both the molten metal feed rate and the solidified ingot withdrawal rate. These speeds are severely limited by heat exchange problems, which reduces the commercial utility of this continuous casting process.

Both are from Finland's Outokunpo Oi (OutO).
kUmDOoy) Transferred to Lohi]Suki (Loh
Ikoski et al., U.S. Pat. No. 3,746,017 and Lohikoski, U.S. Pat.
No. 872,913 describes an ascending casting technique in which freshly formed molten metal is forced up by hydraulic pressure or sucked up by vacuum into a vertically oriented open mechanical mold. According to this method, the cooled cast product is intermittently released from physical contact with the top of a mechanical mold into which molten metal is continuously introduced.

In such a system, the desirable "fail-safe" properties of ascending casting techniques are achieved, but considerable wear on the outer contact mold is inevitable. In fact, during continuous or semi-continuous operation of such systems,
The mold wears out in an unacceptably short amount of time. Therefore, there is a current need for an improved continuous casting system for tubular metal products that overcomes the deficiencies of previously known electromagnetic casting systems.

SUMMARY OF THE INVENTION It is, therefore, a principal object of the present invention to provide a long tubular metal product (
The object of the present invention is to provide a new and improved continuous casting method and apparatus for producing pipes.

According to one of the features of the invention, it minimizes gravitational, frictional and adhesion forces acting on the tubular metal product while maintaining the highest degree of effective heat transfer between the tubular metal product and the heat exchanger during solidification. An improved method and apparatus for continuous manufacturing of elongated tubular metal products (e.g., pipes) by casting in the presence of an upwardly traveling levitation electromagnetic field is provided.

In carrying out the method of the present invention for manufacturing long tubular metal products, an elongated alternating levitation electromagnetic field traveling upward is generated inside an annular casting container; An apparatus is provided that includes means for generating a first confinement electromagnetic field component extending at right angles and extending over the same extent. The apparatus is also for generating a second confinement electromagnetic field component for generating at least a second confinement electromagnetic field component that opposes the first confinement electromagnetic field component in the center of the annular casting vessel. It also includes second electromagnetic field generating means. A tubular molten metal column is formed by introducing molten metal into the annular casting vessel and the bottom of the electromagnetic field. The value of the levitation electromagnetic field acting on the tubular molten metal column is determined by appropriate means such that the levitation electromagnetic field acts on the tubular molten metal column while maintaining a predetermined dimensional relationship between the inner and outer surfaces of the tubular molten metal column and the opposing surrounding surfaces of the annular casting vessel. It is set to reduce the hydrostatic head of the column to a minimum. The electromagnetic field acting on the tubular molten metal column is also such that the cross-sectional dimensions of the tubular molten metal column provide substantial pressure-free contact between the inner and outer surfaces of the tubular molten metal column and the opposing surrounding surfaces of the annular casting vessel. The dimensions are such that no gaps form, thereby achieving pressure-free contact and the highest degree of heat transfer between the tubular molten metal column and the annular "casting vessel, while at the same time minimizing the forces of gravity, friction, and adhesion." In this way, the tubular molten metal column rises within the annular casting vessel while undergoing flotation and solidification within the solidification zone surrounded by the heat exchanger, and the solidified The tubular metal product is removed from the top of the annular casting vessel.

During operation of the continuous casting method, molten metal is continuously introduced into the lower part of the annular casting vessel, and solidified tubular metal products are continuously taken out from the upper part of the annular casting vessel. The production rate of the tubular metal product in that case is determined by controlling the rate of removal of the solidified tubular metal product from the upper part of the annular casting vessel and the corresponding rate of introduction of molten metal into the lower part of the annular casting vessel. Ru.

According to a preferred embodiment of the present invention, the second electromagnetic field generating means is disposed within the center opening of the annular container and generates a levitating electromagnetic field that travels upward. is configured.

To start up the process of the invention, a starting metal tube is joined to a tubular molten metal column that rises in a levitation field. For this purpose, the upper end of the tubular molten metal column in the electromagnetic field may be cooled and solidified while being brought into contact with the lower end of the starting metal tube within the solidification zone.

Also provided is first means for removing the starting metal tube and the solidified tubular metal product attached thereto at a rate that determines the production rate of the tubular metal product. Immediately after the extracted tubular metal product is removed from the upper part of the annular casting vessel, it is pre-cooled, and then optionally rolled to the desired finish state,
It is then cooled to room temperature. Alternatively, if the tubular metal product is cast to the desired dimensions from scratch, it is precooled immediately after leaving the top of the annular casting vessel, then cooled to room temperature and stored.

These and other objects, features, and many of their attendant advantages of the present invention will become readily apparent upon reading the following detailed description in conjunction with the accompanying drawings. In the drawings, like parts are designated by the same reference numerals.

DETAILED DESCRIPTION OF THE INVENTION General Electric Company (Qenera)
1 entitled ``Continuous Metal Casting Methods, Apparatus and Products'' assigned to the Electric Company.
Huqh R. Lowry and Robert T. Frost, November 8, 983.
U.S. Pat. A novel continuous metal casting method, apparatus and product for casting hollow metal rods is disclosed. The present invention is disclosed in U.S. Pat. No. 4,414.
No. 285, an improvement on the '285 patent, extends the principles described therein to disclose a method and apparatus for manufacturing tubular metal products such as pipes and the like.

FIG. 1 is a schematic functional diagram of an improved apparatus suitable for continuously manufacturing elongated tubular metal products in accordance with the present invention using the principles described in U.S. Pat. No. 4,414,285. The apparatus shown in FIG. 1 includes an annular molten metal reservoir 10 into which molten metal from which pipes or other tubular metal products are made is supplied.

It goes without saying that the molten metal reservoir 10 is equipped with suitable refractory liner insulation and heating elements to maintain the molten metal contained therein in a molten state.

At the upper end of the molten metal reservoir 10 is an annular casting container/heat exchanger 1.
1 is arranged, the annular internal passage of which is aligned with and communicates with a correspondingly shaped opening provided in the upper part of the molten metal reservoir 10.

The annular casting vessel and heat exchanger 11 includes a cylindrical outer ceramic liner 12 projecting and supported within an annular passage provided at the top of the molten metal reservoir 10. Also,
An inner ceramic liner 13 is disposed in an inverted state above a central opening 14 formed at the center of the annular molten metal reservoir 10. The side walls of the inner ceramic liner 13, together with the outer ceramic liner 12, define a long-barred annular casting vessel for solidifying the molten metal in the molten metal reservoir 10 into the desired tubular metal product.

In the area immediately above the molten metal reservoir 10, an annular external heat exchanger 15 is arranged around the outer ceramic liner 12. Such an external heat exchanger 15 may be constructed and operated similarly to the heat exchanger described in connection with FIG. 3 of U.S. Pat. No. 44''14285. The disclosures of this book are hereby incorporated by reference into this specification.External heat exchanger 1
At 5, the cold W from the inlet indicated by arrow 16
Water is supplied while hot water is discharged from the outlet indicated by arrow 17. In order to remove heat from the inverted cup-shaped inner ceramic liner 13, an annular internal heat exchanger 18 is provided adjacent to the inner surface of the inner ceramic liner 13.
is physically located. The internal heat exchanger 18 includes an upper header section 18A that contacts the bottom surface of the inverted cup-shaped inner ceramic liner 13 and supplies cooling water to downwardly extending side sections 18B. The downwardly extending lateral portion 18B contacts the downwardly extending lateral portion of the inverted pot-shaped inner ceramic liner 13 which together with the cylindrical outer ceramic liner 12 defines an annular casting vessel for forming a tubular metal product. and then remove the heat. Cooling water is indicated by arrows 19 and 2.
1, it is fed through a central inlet pipe 18C to header section 18A, then branches before passing through downwardly extending side sections 18B of internal heat exchanger 18. The entire structure is secured to a central opening 1 of an annular molten metal reservoir 10 by means of suitable physical supports (not shown).
Physically supported within 4.

Cooling water is thus supplied to the internal heat exchanger 18 through the central inlet pipe 18G, as shown by the arrow 19, through the header portion 18A and the downwardly extending side portions 1.
8B and then exits as indicated by arrow 21 through outlet 1118D.

The outer periphery of the external heat exchanger 15 is surrounded by external multiple windings 22 as shown in FIG.

Such external multiple windings 22 may, for example, be arranged around the outer ceramic liner 12 such that the plane defined by the windings is substantially perpendicular to the central axis of the outer ceramic liner 12.
It can be made up of 12 coils stacked vertically around the periphery of the coil. As described in more detail in the aforementioned U.S. Pat. No. 4,414,285, particularly with reference to FIG. 3 thereof, each coil of external multiplex winding 22 has a 3F! They are connected in sets of 11 to successive phases of a multiphase power supply (FIG. 2), thereby generating an upwardly traveling levitation field.

Similarly, an internal multiple winding 23 is provided consisting of a plurality of coils located in a plane perpendicular to the central axis of the inverted cup-shaped inner ceramic liner 13. Each coil of the internal multiplex winding 23 is wound in the circumferential direction along the inner surface of the side portion 18B of the inverted cup-shaped internal heat exchanger 18. The internal multiplex winding 23 has a conductor 2
Power supply current is supplied via 4. Preferably, the internal multiplex winding 23 is energized with a multiphase power source to generate the second upwardly traveling electromagnetic field, but as explained in more detail in the notes, such internal multiplex winding is combined with a single phase winding. It is also possible to configure it as However, in accordance with a preferred embodiment of the invention, internal multiplex winding 23 is connected as a multiphase winding and multiphase current is supplied via conductors 24.

As a result, an upwardly traveling levitation field is generated that is substantially in phase with the upwardly traveling levitation field generated by the external multiplex winding 22.

The levitation field also has a confinement field component extending in a direction not perpendicular to the upwardly traveling levitation field and acting in a direction opposite to the confinement field component generated by the external multiple windings 22. There is.

FIG. 2 shows the external multiplex winding 1j122 connected to the multiphase power supply/controller 25. In FIG. The polyphase power supply/controller 25 can also independently receive frequency control by a frequency controller 26 of a known type and output level control by an output controller 27 of a known type. Similarly, the internal multiplex winding 23 of FIG. 1 is connected via a conductor 24 to an internal coil power supply and controller 28. The internal coil power supply and controller 28 also includes an independent frequency controller 29 and an independent output controller 3 for controlling the frequency and intensity (output) of the current supplied thereby to the internal multiplex winding 23.
1. As previously mentioned, the internal multiplex winding 23 may consist of a multiphase winding similar to the external multiplex winding 22. In that case, the current supplied from the internal coil power supply and controller 28 via the conductor 24 is a polyphase power supply capable of generating an upwardly traveling levitation field. Preferably, such levitation field is substantially in phase with the upwardly traveling levitation field generated by external multiple windings 22. The levitation field also has a confinement field component extending in a direction substantially perpendicular to the upwardly traveling levitation field and acting in an opposite direction to the confinement field component generated by the external multiple windings 22. are doing.

During operation, molten metal prepared in a furnace (not shown) is supplied to the molten metal reservoir 10 through the feed pipe 10A. The molten metal then rises from the molten metal reservoir 10;
It then enters the lower part of the annular casting vessel defined by the inner surface of the outer ceramic liner 12 and the opposing outer surface of the inverted pot-shaped inner ceramic liner 13. In that case, a molten metal column 32 rising in an annular casting vessel defined between ceramic liners 12 and 13 under gravity flow or by pressurization of an inert gas coating causes the outer multiple winding 22 and the inner multiple winding 23 to It is configured to reach the liquid level just above the lower end.

During continuous operation, in order to maintain this initial liquid level of molten metal in the annular casting vessel 12.13, the holding furnace intermittently or continuously delivers molten metal to the molten metal sump 10 as necessary. Enter. The molten metal at the above initial liquid level will be under the influence of an upwardly traveling levitation field generated by the external multiplex winding 22 and an electromagnetic field generated by the internal multiplex winding 23.

This applies also if the electromagnetic field generated by the internal multiplex winding 23 is a confining field acting only in the horizontal direction, or alternatively if the confining field component of the levitation field generated by the external multiplex winding 22 This also applies to the case of an upwardly traveling levitation field with a confinement field component acting in the opposite direction.

At the start of operation, a starting lifting tubular member (not shown) is introduced from the upper end of the annular casting vessel 12.13, and the lower end of it lifts the tubular melt formed by the molten metal rising into the annular casting vessel 12.13. It is brought into contact with the top end of the metal column. When the cooling water is flowed at full speed through each of the heat exchangers 15 and 18, the upper part of the tubular molten metal column shown at 26 solidifies while contacting the starting lifting tubular member. Then, by means of a suitable take-off roll as shown in FIG.
The starting lifting tubular member and the tubular metal column 26 attached thereto are removed upwardly from the annular casting vessel 12.13.

The withdrawal rate of the starting lift tubular member and the tubular metal column 26 attached thereto is determined by the solid metal formation rate, and the withdrawal rate determines the production rate of the continuous casting system.

Upon coagulation within a coagulation zone essentially defined by the lengths of multiple windings 22 and 23, the above-mentioned U.S. Pat.
As explained in more detail in No. 414,285, the molten and solidified metal columns are maintained in a substantially weightless to pressureless state by an upwardly traveling levitation electromagnetic field.

In operation, the tubular molten metal column within the solidification zone subjected to such flotation effects exhibits unique and unexpected self-regulating properties. Based on this self-adjusting property, when the tubular molten metal column is accelerated upwards because the buoyancy force is greater than the gravitational force acting on it, a reduction in its cross-sectional area occurs.

In that case, a large buoyancy force does not result and the buoyancy force is automatically reduced as a result of the reduction in the cross-sectional area of the tubular molten metal column.

As a result, the system stabilizes and exhibits self-regulating properties since the rise of the tubular molten metal column is automatically slowed down. The same can be said for the reverse case. That is,
When the tubular molten metal column is decelerated due to the reduction of buoyancy force,
An increase in its cross-sectional area results. As a result, the buoyancy force acting on the tubular molten metal column increases, thereby accelerating the ascent of the tubular molten metal column. Thus, within the levitation zone (i.e., the area where the upwardly traveling levitation electromagnetic field acts on the tubular metal column in the molten or solidified state), the tubular molten metal column that solidifies within the solidification zone is substantially The system is found to be essentially self-regulating once it starts operating in a zero-gravity, zero-pressure, buoyant state.

Although most of the length of the molten and solidified tubular metal columns located within the solidification zone are completely affected by the levitation field (the average levitation force is approximately 1/2 compared to the central part of the solidification zone),
The tubular metal column at the lower end and the second end of the solidification zone (no more than 2) has a pressure head applied to raise the molten metal to the initial liquid level and the above-mentioned starting lifting tubular member. each supported by the lift exerted by the As a result, immediately after the formation of the tubular molten metal column, only a small upward acceleration force is exerted by the levitation force in the lower end region, but as the tubular molten metal column rises and reaches the central part of the levitation area, the tubular molten metal column A magnetic field of sufficient strength will be encountered to maintain the metal column in an essentially weightless condition and its contact with the side walls 12 and 13 of the annular casting vessel to be substantially pressure-free. Here, "no pressure J" refers to the inner and outer surfaces of the tubular molten metal column and the annular casting container 1.
2.13 means that there is substantially no continuous pressure contact with the surrounding surface. As a result, a tubular molten metal column within a critical solidification region has no substantial hydrostatic head, and within such a critical solidification region, gravitational, frictional, and adhesion forces acting on a solidifying tubular molten metal column are reduced to a minimum. descend.

The inner diameter of the outer ceramic liner 12 and the outer diameter of the side portions of the inner ceramic liner 13 are such that a small annular gap is formed between the inner and outer surfaces of the tubular molten metal column 32 and the opposing surfaces of the ceramic liners 12 and 13. It is set as follows. This gap is.

Actually, rather than gaps, they are spaces irregularly scattered between the inner and outer surfaces of the tubular molten metal column 32 and the annular casting container, and are too small to be illustrated.

In order to achieve good heat transfer, it is important to keep the dimensions of such gaps to a very small value. Incidentally, in FIGS. 2 and 3 of the above-mentioned US Pat. No. 4,414,285, an attempt is made to illustrate the locations where such gaps exist. However, it should be noted that such illustrations are only schematic and do not truly represent the location or size of the gap. However, such gaps do exist, albeit irregularly scattered, and their presence is evidenced by the shiny, wavy appearance of the surface of the solidified tubular metal product. If the gap becomes too large by increasing the confinement component of the levitating electromagnetic field traveling in the L direction, effective heat transfer between the tubular molten metal column and the opposing inner surfaces of ceramic liners 12 and 13 will be significantly impaired. Sometimes. It is known that a highly inverse relationship exists between electromagnetic field strength and heat transfer rate.

The strength of the levitation field should therefore be set at the beginning of the casting operation to achieve the desired pressure-free contact as defined above while maintaining a small gap that provides good heat transfer. . The electromagnetic field strength should be maintained at this set value during the casting operation, and should not be changed even if the rate at which the tubular molten metal column leaves the solidification zone (linear velocity) changes.

Next, referring to FIG. 2, the solidified tubular metal product taken out from the upper end of the annular casting container is introduced into a precooling chamber 34, passed through take-out rolls 35 and 36, and then passed through two straight tubes. It passes through hot rolling steps 37 and 38 arranged in the roller 14, and finally is cooled in a coiling step 39 and then wound into a coil. Alternatively, if the solidified tubular metal product has a diameter and finish suitable for use as cast, the tubular metal product is removed from the precooling chamber 34 by take-off rolls 35 and 36 and then IM' for further processing? j
It is cooled without any problem and wound up into a coil.

In operation, the casting speed (i.e. the linear velocity of the tubular molten metal column passing through the annular casting vessel and heat exchanger 11) is determined by the drive motors for the take-off rolls 35 and 36 synchronized with the rolling mills 37 and 38 and the coiling mechanism 39. should be regulated by controlling the The strength and excitation frequency of the levitation field should be set at values calculated to allow for levitation ratios in the range of 75-200%, depending on the dimensions and resistivity of the tubular metal product to be cast. In an actual system utilizing the present invention, it is desirable to start operation at a lower than normal linear velocity and a higher than normal float ratio in order to achieve a reliable start. (2~3
After steady-state operating conditions (within 1 minute) are obtained, the molten metal to tubular metal product is The casting speed expressed in conversion tonnage may be adjusted so as to reach around the maximum value. The system is then maintained at this set point throughout the operating time. Usually,
It is desirable to monitor the temperature of solidified tubular metal products to ensure good production performance. For this purpose, the tubular metal product immediately after leaving the annular casting vessel can be monitored by visual inspection or by means of a pyrometer.

INDUSTRIAL APPLICATIONS The invention provides continuous casting of tubular metal products such as pipes in the presence of a levitation electromagnetic field that significantly reduces the high forces and wear found in equipment commonly used in the casting of tubular metal products. A novel method and apparatus for casting are provided.

Although the method and apparatus according to the invention and the solidified tubular metal product obtained thereby have been described above, it will be appreciated by those skilled in the art that other modifications of the invention are possible in light of the above description. Believed to be self-evident. It will therefore be appreciated that various changes may be made to the specific embodiments described above without departing from the scope of the invention as defined by the claims.

[Brief explanation of the drawing]

FIG. 1 is a partial schematic functional diagram of a new and improved apparatus for casting tubular metal products according to the present invention, showing the main components of such apparatus and their interrelationships in the production of tubular metal products according to the invention; It shows. Further, FIG. 2 is a functional block diagram of the entire continuous casting system based on the method of the present invention, using the apparatus shown in FIG. 1. In the figure, 10 is a molten metal reservoir, 11 is an annular casting container/heat exchanger, 12 is an outer ceramic liner, 13 is an inner ceramic liner, 14 is a center opening, 15 is an external heat exchanger, 1
8 is an internal heat exchanger, 22 is an external multiple winding, 23 is an internal multiple winding, 24 is a conductor, 25 is a multiphase power supply/controller, 26 is a frequency controller, 27 is an output controller, and 28 is an internal coil. A power supply/controller, 29 a frequency controller, 31 an output controller,
32 is a tubular molten metal column, 34 is a precooling chamber, 35 and 36 are take-out rolls, 37 and 38 are rolling mills, and 39 is a coiling mechanism.

Claims (1)

[Scope of Claims] 1. (a) Generating an upwardly traveling elongated alternating levitation electromagnetic field within the annular casting container, and extending at right angles to and having the same extent as said upwardly traveling levitation electromagnetic field. (b) generating at least a second confinement electromagnetic field component in a central portion of the annular casting vessel that acts in an opposite direction to the first confinement electromagnetic field component; (c) introducing molten metal into a lower portion of the annular casting vessel and the electromagnetic field to form a tubular molten metal column; (d) opposing inner and outer surfaces of the tubular molten metal column and opposing surrounds of the annular casting vessel; The value of the levitation electromagnetic field acting on the tubular molten metal column is set so as to reduce the hydrostatic head of the tubular molten metal column to a minimum while maintaining a predetermined dimensional relationship with a surface; ) the cross-sectional dimensions of the tubular molten metal column are large enough to provide pressure-free contact but do not form a substantial gap between the inner and outer surfaces of the tubular molten metal column and opposing surrounding surfaces of the annular casting vessel; and thereby achieving pressureless contact and the highest degree of heat transfer between the tubular molten metal column and the annular casting vessel while reducing gravitational, frictional and adhesion forces to a minimum. maintaining the value of said electromagnetic field so that (f)
raising the tubular molten metal column within the annular casting vessel; (g) solidifying the molten metal while ascending within the annular casting vessel and through the electromagnetic field; and (h) increasing the top of the annular casting vessel. A method for manufacturing a long tubular metal product, comprising the steps of taking out a solidified tubular metal product from a solidified tubular metal product. 2. In the case where continuous casting is carried out in which molten metal is continuously introduced into the lower part of the annular casting container and solidified tubular metal products are continuously taken out from the upper part of the annular casting container, the production rate of the tubular metal product is determined by controlling the rate of removal of the tubular metal product from the upper part of the annular casting vessel and the corresponding rate of introduction of molten metal into the lower part of the annular casting vessel;
2. The method of claim 1, wherein said second confinement field component is provided by a second upwardly traveling levitation field acting within a central opening of said annular casting vessel. 3. The molten metal column extending upward in the electromagnetic field is in a weightless state such that the tubular molten metal column has substantially no hydrostatic head over most of its length located in the electromagnetic field. and the strength of the electromagnetic field is set to maintain a predetermined dimensional relationship between the inner and outer surfaces of the tubular molten metal column and opposing surrounding surfaces of the annular casting vessel, such that the tubular molten metal column The cross-sectional dimensions of the tubular molten metal column are maintained at values that prevent substantial continuous pressure contact between the inner and outer surfaces of the tubular molten metal column and the opposing surrounding surfaces of the annular casting vessel while The molten metal column has no substantial hydrostatic head, thereby allowing the tubular molten metal during solidification to flow without impairing heat transfer between the solidifying tubular molten metal column and the annular casting vessel within the solidification zone. 3. A method according to claim 2, wherein the gravitational, frictional and adhesion forces acting on the metal column are reduced to a minimum. 4. As an initial step, the starting metal tube is cooled and solidified while bringing the lower end of the starting metal tube into contact with the upper end of the tubular molten metal column rising in the electromagnetic field. 4. The method of claim 3, wherein the method is joined to a tubular molten metal column. 5. Introducing molten metal into the lower part of the upwardly traveling elongated levitating electromagnetic field and the confining electromagnetic field component cooperating therewith, so that the inner and outer surfaces of the tubular molten metal column and the opposing surrounding surfaces of the annular casting vessel conditions are set such that the hydrostatic head of the tubular molten metal is reduced to a minimum while maintaining a predetermined dimensional relationship between and opposing surrounding surfaces of the annular casting vessel to provide the highest degree of heat transfer between the tubular molten metal column and the annular casting vessel. maintaining the values of the levitation field and the confinement field components such that gravity, frictional and adhesion forces are reduced to a minimum, and the tubular molten metal column A shiny wavy shape having substantially uniform composition and diameter produced by solidifying said tubular molten metal column while rising through and being agitated by a confining electromagnetic field component. Product obtained from the process according to claim 1, characterized in that it consists of a sufficiently dense continuous metal tube exhibiting a surface of . 6. (a) an elongated annular casting vessel disposed in an upright position for containing molten metal to be solidified; (b) for supplying molten metal to the lower part of said annular casting vessel to form a tubular molten metal column; (c) heat exchange means coupled to the annular casting vessel for cooling and solidifying the tubular molten metal column; (d) means for removing the solidified tubular metal product from the top of the annular casting vessel; , (e) a first levitation electromagnetic field generating means disposed around the outer periphery of the annular casting container along a portion of the length of the annular casting container;
f) at least a second levitating electromagnetic field component acting in a direction opposite to the confining electromagnetic field component generated by the first levitation electromagnetic field generating means;
a second electromagnetic field generating means disposed in the center of said annular casting vessel for generating a confining electromagnetic field component of said tubular melting vessel; (g) serving to lower the hydrostatic head of the metal column and maintain a predetermined dimensional relationship between the inner and outer surfaces of the tubular molten metal column and the opposing surrounding surfaces of the annular casting vessel; the tubular molten metal column by having cross-sectional dimensions of the column such that no substantial gap is formed between the inner and outer surfaces of the tubular molten metal column and opposing surrounding surfaces of the annular casting vessel; maintaining the values of the levitation field and the confinement field components such that the highest degree of heat transfer is achieved between the levitation field and the annular casting vessel while gravitational, frictional and adhesion forces are reduced to a minimum; and (h) means equipped independently of said first levitating electromagnetic field generating means and said second electromagnetic field generating means for raising said tubular molten metal column within an annular casting vessel. Continuous casting equipment for metal products. 7. In the case where the second electromagnetic field generating means also comprises a levitating electromagnetic field generating means, both of the first and second levitating electromagnetic field generating means are connected to successive phases of a multiphase power supply and are directed upwardly. 7. The device of claim 6, comprising a plurality of electromagnetic coils for generating a traveling alternating electromagnetic field. 8. A molten metal reservoir for containing a molten metal bath is disposed in communication with the lower end of the annular casting vessel, and forming a tubular molten metal column within the annular casting vessel and at least the first levitation electromagnetic field. 8. The apparatus of claim 7, further comprising means coupled to said molten metal reservoir for raising said tubular molten metal column to a liquid level above the lower end of said generating means. 9. A patent in which said multilayer power source consists of a three-phase generator whose output and frequency can be set to produce a uniform, balanced, upwardly traveling levitation electromagnetic field depending on the type of tubular metal product to be cast. Apparatus according to claim 8. 10. For use during initial start-up of the apparatus, solidify the tubular molten metal column by bringing the lower end of the lifting metal tube into contact with the upper end of the tubular molten metal column in the solidification zone and then solidifying the tubular molten metal column. Claims comprising means for joining the lifted metal tube to its upper end and means for removing the lifted metal tube and the solidified tubular metal column attached thereto at a rate that determines the production rate of the tubular metal product. The device according to item 9. 11. Means for pre-cooling the solidified tubular metal product immediately after leaving the upper part of the annular casting vessel, means for rolling the tubular metal product to a desired size, and the tubular metal product after rolling. 11. The apparatus according to claim 10, further comprising means for cooling the liquid to room temperature. 12. A patent claim comprising means for pre-cooling the solidified tubular metal product immediately after detachment from the upper part of the annular casting container and means for cooling the pre-cooled tubular metal product to room temperature. The device according to scope 10. 13. The apparatus of claim 6, wherein said second electromagnetic field generating means comprises single phase confinement electromagnetic field generating means for generating an outward confinement electromagnetic field acting on said tubular molten metal column. 14. For use during initial start-up of the apparatus, the tubular molten metal column is solidified by contacting the lower end of the lifting metal tube with the upper end of the tubular molten metal column in the solidification zone; Claims comprising means for joining the lifted metal tube to its upper end and means for removing the lifted metal tube and the solidified tubular metal column attached thereto at a rate that determines the production rate of the tubular metal product. The device according to item 13. 15. (a) forming a tubular molten metal column; and (b) electromagnetically levitating a substantial portion of the tubular molten metal column within the solidification zone while the tubular molten metal column enters the solidification zone; lowering the hydrostatic head of the tubular molten metal column;
and (c) electromagnetically confining the tubular molten metal column so that a predetermined dimensional relationship is established between the inner and outer surfaces of the tubular molten metal column and the surrounding surface of the casting container; (c) traversing the tubular molten metal column; the tubular molten metal column and the casting vessel by having surface dimensions such that no substantial gap is formed between the inner and outer surfaces of the tubular molten metal column and the surrounding surface of the casting vessel; maintaining the values of the levitation field and the confinement field such that pressure-free contact and the highest degree of heat transfer are achieved while gravitational, frictional and adhesion forces are reduced to a minimum; (d) A continuous casting method for a long tubular metal product, comprising the steps of removing the solidified tubular metal product from the solidification zone while electromagnetically holding the tubular molten metal column. 16. Electromagnetically so that a majority of the length of the tubular molten metal column within the solidification zone establishes a predetermined dimensional relationship between the inner and outer surfaces of the tubular molten metal column and the surrounding surface of the casting container. As a result, the cross-sectional dimensions of the tubular molten metal column avoid substantial continuous pressure contact between the inner and outer surfaces of the tubular molten metal column and the surrounding surface of the casting vessel to avoid pressureless contact. while the tubular molten metal column has no substantial hydrostatic head thereby solidifying without substantially impairing heat transfer between the tubular molten metal column and the casting vessel during solidification. 16. The method of claim 15, wherein gravitational, frictional and adhesion forces acting on said tubular molten metal column therein are reduced to a minimum. 17. The tubular molten metal column is continuously formed and enters the solidification zone, while the solidified tubular metal product is continuously removed from the solidification zone by means other than the levitation electromagnetic field; 17. The method of claim 16, whereby the production rate of the tubular metal product is controlled. 18. The method of claim 17, wherein said upwardly traveling levitation electromagnetic field has a frequency greater than 1 kilohertz. 19. Depending on the type and dimensions of the tubular metal product to be cast, the strength of the levitation electromagnetic field is set to give a levitation ratio of 75 to 200% based on the weight per unit length of the tubular molten metal column. 18. The method according to claim 17. 20. The distinctive luster of the tubular molten metal column when solidification takes place in the presence of a levitation electromagnetic field acting on and agitating the column while it is not in continuous pressure contact with the casting vessel. Solidified tubular metal article produced according to the method of claim 17, characterized in that it exhibits a certain wavy surface.