EP2501507A1

EP2501507A1 - Continuous casting nozzle for a rod, wire or pipe in upward vertical metal casting

Info

Publication number: EP2501507A1
Application number: EP10795408A
Authority: EP
Inventors: Markku Koivisto; Esko Furuholm; Juha Jaakola; Jukka LÄHTEENMÄKI; Pertti PIHLAJAMÄKI; Tuomas Rajaviita; Ismo Rossi
Original assignee: Upcast Oy
Current assignee: Upcast Oy
Priority date: 2009-11-18
Filing date: 2010-11-17
Publication date: 2012-09-26
Anticipated expiration: 2030-11-17
Also published as: CL2012001287A1; FI20096197A7; ES2589410T3; FI124847B; PL2501507T3; FI20096197A0; EP2501507B1; WO2011061397A1

Abstract

The invention relates to a continuous casting nozzle, which is suitable for the continuous upward vertical casting of a metal (M) for uninterrupted castings (P). A nozzle (1 ) comprises a cooling mantle (30), as well as a mold component (2) which consists of a refractory material. The mold component has its upper end (2y) extending coaxially into an interior of the cooling mantle and in attachment therewith by a heat transfer joint (9). The mold component is provided with an internal cross-section surface (12), which defines an elongated continuous casting mold cavity (20) co-directional with a center axis and which matches the presently produced casting (P) in terms of the latter's outer shape and outer dimensions (11 ). The mold component comprises one or more tangential melt feed holes (3) at a first distance (R1 ) from a center axis (10), said distance being greater than a second distance (R2) of the continuous casting mold cavity's (20) internal surface (12) from the center axis, as well as an annular flow gap (4) connecting said one or more tangential melt feed holes (3) with the continuous casting mold cavity (20). The flow gap has its inner edge (4s) provided with a circumferential gap cross-section area (A4) which is smaller than a sum of the melt feed holes' (3) cross-sectional hole areas (A3).

Description

Continuous casting nozzle for a rod, wire or pipe in upward vertical metal casting

The invention relates to a continuous casting nozzle, which is suitable for the continuous upward vertical casting of a metal for uninterrupted castings, said nozzle comprising: a cooling mantle having a top section and a bottom section; a mold component consisting of a refractory material and having an upper end and a lower end, said upper end extending coaxially into the interior of said cooling mantle and being by a heat transfer joint in attachment with said cooling mantle, and said lower end protruding from the cooling mantle, and said mold component having an internal cross-sectional surface, defining an elon- gated, continuous casting mold cavity co-directional with a center axis and matching the presently produced casting in terms of its outer shape and outer dimensions. The invention relates also to a mold component for the upward vertical casting of a metal rod, wire or pipe, said mold component having its internal surface, which defines a continuous casting mold cavity, matching with its mold cross-section area the presently produced rod/wire/pipe in terms of its outer shape and outer dimensions, and said mold component having a center axis, as well as a lower end and an upper end, said lower end being suitable for submersion in a molten metal, and being attachable at its upper end to cooling means, said mold component being constructed in at least one piece of a refractory material. The invention relates further to a continuous casting method of casting a rod or wire or pipe vertically upwards, said method comprising: feeding a molten metal to a lower end of an elongated mold component containing a continuous casting mold cavity vertical in terms of its center axis; allowing the molten metal to solidify to a solid state by cooling the mold component with a cooling mantle; and pulling the solidified, solid state metal in the form of a wire or rod or pipe out of an upper end of the mold component at a casting ve- locity. And, the invention relates also to the use in further processing of a casting produced with the defined method and the defined equipment.

Publication GB 2 168 633 describes a rotary supply apparatus for a cast-iron vertical casting installation, the question thus being about a variant of centrifugal casting. The installation includes a die component cooled over its entire length and constituting a crucible type reservoir for molten cast-iron. This reservoir crucible containing spheroidal graphite cast- iron is characterized in that it comprises, at least at its lower end, means for setting the mass of molten cast-iron contained in the said reservoir crucible in low rotation having a horizontal component. Said slow rotation can be induced in cast-iron contained in the reservoir by hydraulic means, such as by means of one or more nozzles present in a lower section of the reservoir crucible, whereby said slow rotation can be achieved particularly by rhythmic pulses of molten cast-iron from a siphon unit. Preferably, most of the molten metal is supplied along an axial inlet pipe to the bottom of the reservoir crucible, but it can also be supplied along a tangential inlet pipe to the bottom of the reservoir crucible. It is also possible to use jets of an inert gas or magnetic means or mechanical means for setting the melt in the reservoir in slow rotation. This installation enables a reduction of cool- ing-induced temperature differences in the reservoir crucible and a solidification of an appropriately thick pipe-forming layer on the die surface.

A traditional arrangement for casting a wire, bar or pipe in continuous casting directed upwards from a free melt surface is disclosed for example in patent Fl 46810 (~ US 3,872,913), which describes a method and apparatus for the upwards casting of profiled products, such as bars, plates and pipes, wherein melt is sucked by means of a nozzle, establishing a mold above its surface and having its lower end immersed in the melt, and being connected at its upper end by way of a cooler-surrounded pipe to a cooler support and to a source of vacuum. The cooler consists of three concentric pipes, between which extend cylindrical channels for cooling water. The innermost pipe has a cross-section larger than that of the profiled article. The nozzle is constructed in a single piece of refractory material and extends by its upper end coaxially into the cooler. The cooler support has an opening that matches an article to be cast and, as the mold is connected with a further cooling zone more extensive than this, said source of vacuum enables sucking melt into the cooling zone present within the nozzle. A variant of the above-discussed traditional arrangement is disclosed in the application publication GB 2 080 715, according to which a dense, homogeneous and long metal rod can be continuously cast by establishing an elongated, upwardly-extending alternating electromagnetic field, by introducing molten metal into the lower portion of this field, solidifying the metal while moving upwardly through the field, and removing solidified metal rod product from the upper portion of said field. For this purpose, the continuous casting apparatus of the publication comprises an elongated tubular casting vessel disposed in upright position to receive molten metal for solidification, means for delivering molten metal into a lower portion of the vessel, heat exchange means associated with the vessel for cooling and solidifying molten metal therein, means for removing solidified metal from an upper portion of the vessel and electromagnetic levitation means disposed around the vessel along a portion of its length to produce an upward lifting effect in a column of molten metal in the vessel. The publication also mentions that the employed electromagnetic field is capable of levitating the weight of an upwardly-moving metal column, advancing the metal column upward, maintaining the metal column under control and out of contact with the surrounding tube, as well as establishing a stirring effect for the homogenization of solidi- tying metal. This stirring of molten metal is produced in response to electrical eddy currents induced in molten metal.

The rod, wire or pipe cast by means of such traditional upwards casting nozzles can be good and dimensionally precise in visual examination, but the wire may have an internal composition which is unfit for further shaping. For example, the grain size within a wire can be excessive. A large grain rod, wire or pipe ruptures in further shaping at grain boundaries and the product is useless. The most traditional pipe manufacturing process involves first melting and casting a block, preheating and extruding the block, followed by Pilger rolling. An alternative is a Cast & Roll process, which involves melting of metal and horizontal casting a thick-walled pipe, followed by machining the pipe surface and planetary milling. These are highly complicated and hard-to-control processes.

The problems of prior art continuous casting nozzles can be resolved with a continuous casting nozzle of the invention, which is characterized by what is defined in the characterizing clause of claim 1 , and with a mold component of the invention, which is characte- rized by what is defined in the characterizing clause of claim 4, as well as with a continuous casting method of the invention, which is characterized by what is defined in the characterizing clause of claim 13.

The invention will now be described in detail with reference to the accompanying drawings. Fig. 1 shows schematically a continuous casting nozzle of the invention and a corresponding mold component in a first embodiment for casting a rod or wire by an upward vertical casting process in a longitudinal section extending through the center axis, along a plane l-l in fig. 4.

Fig. 2 shows schematically a continuous casting nozzle of the invention and a correspond- ing mold component in a second embodiment for casting a rod or wire by an upward vertical casting process in a longitudinal section extending through the center axis, along a plane ll-ll in fig. 5.

Fig. 3 shows schematically a mold component of the invention in a third embodiment for casting a rod or wire by an upward vertical casting process in a longitudinal section ex- tending through the center axis, along a plane Ill-Ill in fig. 6.

Fig. 4 shows a mold component of the fig. 1 embodiment in a cross-section at the flow gap, along a plane IV-IV in fig. 1 . Fig. 5 shows a mold component of the fig. 2 embodiment in a cross-section at the flow gap, along a plane V-V in fig. 2.

Fig. 6 shows a mold component of the fig. 3 embodiment in a cross-section at the flow gap, along a plane VI-VI in fig. 3. This figure also depicts in dashed arrows one possible type of turbulence of molten metal.

Fig. 7 shows schematically a lower peripheral jet speed for molten metal at a large hole distance corresponding to a large peripheral length, and respectively a higher peripheral mold speed at a smaller surface distance corresponding to a small peripheral length. It should be noted that this only shows the principle of speed change, not any numerical values.

The question is about a continuous casting nozzle 1 , which is suitable for the continuous upward vertical casting of a metal M and which enables producing uninterrupted rod type, wire type or tubular castings P. Such a continuous casting nozzle 1 comprises first of all a cooling mantle 30 having a top section 1 y and a bottom section 1 a. The continuous cast- ing nozzle 1 is attached at the top section 1y of its cooling mantle 30 by some appropriate means to fixed support structures, not shown in the figures. The bottom section 1 a of the continuous casting nozzle's 1 cooling mantle 30 is in a configuration that enables the attachment of a mold component 2 thereto by a heat transfer joint 9. For this - and of course for cooling - the cooling mantle may have concentrically disposed a first outermost tube portion 31 , a second middle tube portion 32, and a third inner tube portion 33, and therebetween two cylindrical passages 34a, 34b co-directional with the tube portions and suitable for a flow-through of cooling water W, i.e. for inducing a flow of water through the passages or allowing a flow through the passages. Thus, during operation of the continuous casting nozzle 1 , the cooling water W is induced to flow first along one passage 34a be- tween the tube portions, which passage is usually, but not necessarily, the outer one of these two passages, from the top section 1y of the cooling mantle towards its bottom section 1 a and then from the bottom section 1 a back towards the top section 1y along the other passage 34b, and finally out of the cooling mantle. In other words, the cooling water W flows within the cooling mantle along a U-shaped path, thus circling around a lower edge of the middle tube portion 32 as presented in figs. 1 and 2. For supply and discharge of the cooling water W, the cooling mantle 10 has its top section provided with water connections, not shown in the figures. Also other or other type cooling elements and/or cooling fluids can be used. The cooling mantle 30 has its top section provided at least with fastening elements for the continuous casting nozzle 1 as well as with a penetration open- ing 23 for pulling the uninterrupted casting P out as it is produced. Secondly, such a continuous casting nozzle 1 also comprises a mold component 2, which consists of a refractory material and which has an upper end 2y and a lower end 2a, said upper end extending for example coaxially into the interior of a cooling mantle 30 and being in attachment with the cooling mantle by a heat transfer joint 9. The mold component 2 has its lower end 2a protruding from the cooling mantle 30 to enable its immersion in molten metal M contained for example in a furnace or crucible, as visualized in figs. 1 and 2. The mold component 2 has an inner cross-sectional surface 12, which defines an elongated continuous casting mold cavity 20 co-directional with a center axis 10 and which has a cross-sectional mold area A2 and which matches an outer shape and outer dimensions 1 1 of the presently produced casting P. The junction area between the mold component 2 and the cooling mantle 30 is coated or wrapped with an appropriate heat insulation 19 in order to not damage the cooling mantle 30 as the lower end 2a of the mold component 2, and possibly that lower part 18 of the cooling mantle with which the mold component 2 is in attachment, is immersed in molten metal. The mold component 2 is constructed in at least one piece of an appropriate refractory - i.e. said molten metal resistant - material. The mold component according to the invention comprises one or a plurality of tangential melt feed holes 3 at a hole distance R1 from the mold component's 2 and hence also of the casting's P center axis 10. The hole distance R1 is greater than a surface distance R2 of the continuous casting mold cavity's 20 internal surface 12 from the center axis 10. "Tangential" in this context refers to a direction which at least has a tangentially directed main component, but sometimes also a radially directed component. Hence, the tangential melt feed holes 3 produce their number-matching, i.e. one or a plurality of tangential molten metal jets S1 , S2, which has/have a jet velocity. The jet velocity/jet velocities has/have a peripheral velocity component or peripheral jet velocity V_T, and often also a radially directed velocity component, which points towards the center axis and which is usually much smaller than the peripheral jet component and which is therefore not shown in the figures. Generally, the melt feed holes 3 are directed in such a way that the radially directed velocity component is as small as possible or does not exist at all, whereby the peripheral jet velocity V_T becomes relatively large. Each melt feed hole 3 has a hole cross- section A3, which may be unequal or equal with respect to each other and whose total combined cross-sectional area is marked with∑A3. Generally, the number of melt feed holes is two or more. The size of melt feed holes depends on the size and cross-sectional area of the casting P, but it is often within the diameter range of 1 mm to 10 mm. The mold component comprises also an annular flow gap 4, connecting said one or more tangential melt feed holes 3 with the continuous casting mold cavity 20. Preferably, yet not necessarily, this annular flow gap 4 is in a radial direction - here the radius corresponds to directions of the distances R1 , R2 from the center axis 10, as obvious for a skilled person - converging from an outer circumferential edge 4u closer to the tangential melt feed holes towards an inner inside edge 4s closer to the mold component's center axis 10. In other words, the annular flow gap 4 has its inner edge 4s, which is closer to the center line 10, provided with a circumferential gap cross-section area A4, whose height is the gap's dimension parallel to the center axis 10 and whose width is a circumferential length perpen- dicular to the gap's radius. The flow gap 4 has its size determined by the casting P and by the size and number of the tangential melt feed holes 3, but the above-mentioned height of the gap is generally in the order of 1 mm to 10 mm. The sum∑A3 of cross-sectional hole areas A3 of the tangential melt feed holes 3 is substantially smaller than a cross- sectional mold area A2 of the mold component's 2 internal surface 12, which is thus an area perpendicular to the center axis 10 defined by the mold cavity's 20 walls. In the process of manufacturing a rod or strand, the wall is only formed by an inner face 12' of the cross-sectional internal surface 12 open towards the center axis and, in the process of manufacturing a pipe, the wall is formed by the inner face 12' of the cross-sectional internal surface 12 open towards the center line and by an outer face 12" of a mandrel's 7 core 5. Hence, the cross-sectional mold area A2 is defined either by the inner face 12' alone or by both the inner face 12' and the core's outer face 12". The sum∑A3 of cross-sectional hole areas is typically not more than 20% of the cross-sectional mold area A2 of the mold component's 2 internal surface 12, and it is possibly/probably preferred that the sum∑A3 of cross-sectional hole areas be not more than 12% of the cross-sectional mold area A2 of the mold component's internal surface 12. The inner edge 4s of the annular flow gap 4, which edge is thus closer to the center axis than the outer edge 4u of the flow gap 4, has its circumferential gap cross-section area A4 less than 80% of the cross-sectional mold area A2 of the mold component's internal surface 12. The annular flow gap 4 can be tapered upwards, i.e. in the direction of a casting velocity V_M, as shown in figs. 1 and 2, or tapered downwards, i.e. in a direction reverse to the casting velocity, as schematically marked in fig. 2 with dotted lines, or are perpendicular to the center axis 10 and the casting velocity V_M. The annular flow gap 4 forms an average cone angle K relative to the center axis 10, which angle can be within the range of 10° to 170°, but likely most preferably within the range of 60° to 120°. The mold component's 2 jacket 6 and mandrel 7 can be made of different materials or the same material.

The mold component 2 has its upper end 2y provided with an outer diameter d_Y, which is typically smaller than an outer diameter d_A of the lower end 2a at least by the extent of a heat transfer joint 9. Hence, the cooling mantle 30 provides an enhanced cooling effect on metal contained in the continuous casting mold cavity 20 as a result of the upper end's small outer diameter d_Y. At the same time, this enables fitting a mandrel 7 inside or outside the large diameter lower end 2a. Thus, the mold component 2 comprises a jacket 6 and the mandrel 7. In this case, the jacket 6 makes up the mold component's 2 lower end 2a and the upper end 2y, and inside the jacket's upper end 2y the mold component's elongated continuous casting mold cavity 20 extends co-directionally with the center axis 10 and opens upwards to enable a continuously cast rod, wire or pipe, i.e. the casting P, to be produced and to egress upwards in a direction opposite to the direction of gravity. Typically, the tangential melt feed holes 3 exist in this jacket, but is should be appreciated that, by designing the jacket and mandrel in some other way, the tangential melt feed holes 3 could alternatively exist also in the mandrel 7. The mandrel 7 is present inside or outside the mold component's 2 lower end 2a and constitutes there a plug closing the continuous casting mold cavity 20 downward. The annular flow gap 4 is present between an inward face 16 of the jacket 6 and an upper face 17 of the mandrel 7.

The mandrel 7 included in the mold component extends, in a first option, co-directionally with the center axis 10 from below only to the bottom side level of the flow gap 4, whereby the question is about a mold component 2 useful in the continuous casting of a rod or wire, as depicted in figs. 1 , 3, 4 and 6. In a second option, the mandrel 7 included in the mold component extends in the form of a core 5 co-directionally with the center axis 10 from below into an interior of the mold cavity 20 to a location between its internal surfaces 12 upward of the flow gap 4 to a mandrel length L, whereby the question is about a mold component 2 useful in the continuous casting of a pipe, as depicted in figs. 2 and 5.

The continuous casting method of casting a rod or strand or pipe vertically upward com- prises feeding molten metal M to a lower end 2a of an elongated mold component 2 containing a continuous casting mold cavity 20 vertical in terms of its center axis 10, allowing the molten metal to solidify to a solid state by cooling the mold component 2 with a cooling mantle 30, and pulling the solidified, solid state metal in the form of a wire or rod or pipe out of an upper end 2y of the mold component 2 at a casting velocity V_M. According to the invention, the molten metal M present inside the continuous casting mold cavity 20 is set in a rotating flow motion proceeding around the center axis 10 by using one or more tangential molten metal jets S1 , S2, which have been created by molten metal flowing through the melt feed holes 3. This rotating flow motion, such as turbulence, typically incorporates both a velocity component proceeding around the center axis 10, i.e. a peripheral mold velocity V_D, and velocity components proceeding around other axes co- directional with the center axis, as can be appreciated from fig. 6. The molten metal jets S1 , S2 have the peripheral jet velocity V_T, and these jets S1 , S2 are of course at the hole distance R1 of the tangential melt feed holes 3 from the center axis 10. The continuous casting mold cavity 20 has its internal surface 12, against which the subsequent casting P solidifies, at the surface distance R2 from the center axis 10, this distance being smaller than the hole distance R1 . Consequently, the molten metal M progresses from a rotary flow motion, which proceeds at the larger hole distance R1 and hence has the peripheral jet velocity V_T, into a rotary flow motion proceeding at the smaller surface distance R2 and having the peripheral mold velocity V_D. Because the momentum remains the same, the rotary flow motion proceeding around the center axis 10 has a peripheral mold velocity V_D which is higher than the peripheral jet velocity V_T, thus enabling a decisive enhancement in the turbulence of solidifying metal in the continuous casting mold cavity 20. The larger a difference AR is made between the surface distance R2 and the hole distance R1 , wherein AR=R1 -R2, by widening in a radial direction, i.e. in the direction of the above- mentioned distances, the flow gap 4 connecting the same, the higher a peripheral mold velocity V_D will be obtained with respect to the peripheral jet velocity V_T. The tangential peripheral jet velocity V_T is typically higher than said casting velocity V_M or typically at least eight times higher than said casting velocity V_M. In fig. 7 are depicted the above- mentioned tangential velocities, i.e. the higher peripheral mold velocity V_D over a small peripheral length K2 corresponding to the surface distance R2, wherein K2=2nxR2, and re- spectively the lower peripheral jet velocity V_T over a large peripheral length K1 corresponding to the hole distance R1 , wherein K1 =2nxR1.

This improved continuous casting nozzle, mold component, and continuous casting method enable achieving a small grain size in the casting P as the molten metal present within the mold component 2 - i.e. within the continuous casting mold cavity 20 - is set in ro- tation or turbulence, said rotation or turbulence being further accelerated by a specially design of the nozzle 1 , in which use is made of a sustained quality of the spinning energy existing in rotation. The melt's rotation/turbulence disturbs nucleation at a boundary surface between molten and solid matter, i.e. on a solidification front S, and in a possible two phase region of metal solidification. A disturbance of the solidification front S enables achieving a small grain size, which is beneficial e.g. in further shaping. This improved continuous casting nozzle, mold component, and continuous casting method can be used particularly for the continuous casting of DHP copper, but also pure oxygen-free copper, copper alloys, aluminum and aluminum alloys.

The continuous casting nozzle, mold component, and continuous casting method accord- ing to the invention, and particularly the continuous casting nozzle-cooler arrangement, enable the use of a continuous vertical casting process so as to directly produce by casting a desired type of wire, rod and pipe, the further shaping of which for a thinner and/or thinner-walled rod, wire or pipe is easier than that of a traditional preform having a large grain size. Preforms manufactured from certain copper alloys, such as for example brass, with a high zinc concentration, lend themselves relatively easily to further shaping according to the invention, even though the further shaping of traditionally manufactured pre- forms is almost impossible. All that is performed according to the invention is melting and vertical casting and the obtained casting is without further processing suitable for further shaping e.g. at a pipe manufacturing plant, the end product being for example a sanitary or ACR pipe.

Claims

1. A continuous casting nozzle adapted for a continuous upward vertical casting of metal (M) for uninterrupted castings (P), said nozzle (1 ) comprising:

- a cooling mantle (30) having a top section (1y) and a bottom section (1 a);

- a mold component (2) made of refractory material and having an upper end (2y) and a lower end (2a), said upper end extending coaxially into the interior of said cooling mantle (30) and being by a heat transfer joint (9) in attachment with said cooling mantle, and said lower end (2a) protruding from the cooling mantle (30) for submersion into the molten metal (M), and said mold component (2) having an internal cross-sectional surface (12), defining an elongated, continuous casting mold cavity (20) co-directional with a center axis (10) and matching the casting (P) to be produced in terms of its outer shape and outer dimensions (1 1 ),

characterized in that said mold component (2) comprises one or more tangential melt feed holes (3) at a hole distance (R1 ) from the center axis (10), said distance being greater than a surface distance (R2) of the continuous casting mold cavity's (20) internal surface (12) from said center axis, as well as an annular flow gap (4) connecting said one or more tangential melt feed holes (3) with the continuous casting mold cavity (20), whereby the flow gap (4) has its inner edge (4s) provided with a circumferential gap-cross-section area (A4) which is smaller than a sum (∑A3) of the melt feed holes' (3) hole-cross- sectional areas (A3).

2. A continuous casting nozzle according to claim 1 , characterized in that the mold component's (2) upper end (2y) has an outer diameter (d_Y), which is smaller than the low- er end's (2a) outer diameter (d_A) at least over the length of said heat transfer joint (9), resulting in the cooling mantle (30) having an enhanced cooling effect on the metal present in the continuous casting mold cavity (20).

3. A continuous casting nozzle according to claim 1 or 2, characterized in that said mold component (2) comprises a jacket (6) and a mandrel (7), whereby:

- the jacket (6) defines the elongated continuous casting mold cavity (20) for the mold component (2);

- said tangential melt feed holes (3) exist in the jacket (6);

- the mandrel (7) lies inside or outside the mold component's (2) lower end (2a) and con- stitutes a plug closing the continuous casting mold cavity (20) downward for rod/wire casting, or additionally a core (17) in the continuous casting mold cavity for pipe casting; and

- the sum (∑A3) of the tangential melt feed holes' (3) hole-cross-sectional areas (A3) is smaller than said mold cross-section area (A2).

4. A mold component for the upward vertical casting of metal rod, wire or pipe, said mold component (2) having its internal surface (12), which defines a continuous casting mold cavity (20), matching with its mold cross-section area (A2) a rod/wire/pipe (P) to be produced in terms of its outer shape and outer dimensions (1 1 ), and said mold component having a center axis (10), as well as a lower end (2a) and an upper end (2y), said lower end adapted for submersion in a molten metal (M), and being attachable at its upper end to cooling devices, said mold component (2) being constructed of at least one piece of refractory material, characterized in that said mold component (2) comprises:

- at least one tangential melt feed hole (3), said tangent (13) having its tangential point (T) at a radial hole distance (R1 ) from the mold component's (2) center axis, which hole distance is greater than a surface distance (R2) from said center axis (10), which surface distance is co-directional with a radius of the internal surface (12) of the mold component, whereby a sum (∑A3) of said tangential melt feed holes' (3) cross-sectional hole areas (A3) is smaller than said mold cross-section area (A2); and

- an annular flow gap (4), which connects the at least one tangential melt feed hole (3) and the mold component's (2) continuous casting mold cavity (20) with each other and which has its inner edge (4s), towards the center axis (10), provided with a circumferential gap-cross-section area (A4) which is smaller than said sum (∑A3) of the hole-cross- sectional areas.

5. A mold component according to claim 4, characterized in that the lower end (2a) of said mold component (2) has an outer diameter (d_A) which is greater than an outer diameter (d_Y) of the mold component's upper end (2y).

6. A mold component according to claim 4, characterized in that said annular flow gap (4) is converging from a radially outer peripheral edge (4u), which is closer to the tangential melt feed holes, towards a radially inner peripheral edge (4s), which is closer to the center axis (10).

7. A mold component according to claim 4 or 6, characterized in that said circumferential gap-cross-section area (A4) of the annular flow gap's (4) inner edge (4s) is at maximum equal to the mold cross-section area (A2) of the mold component's (2) internal surface (12), and that said circumferential gap-cross-section area (A4) is less than 80% of the mold cross-section area (A2) of the mold component's internal surface (12).

8. A mold component according to claim 4 or 6, characterized in that said sum (∑A3) of the tangential melt feed holes' (3) hole-cross-sectional areas is not more than 20% of the mold cross-section area (A2) of the mold component's (2) internal surface (12), and that said sum (∑A3) of the hole-cross-sectional areas is not more than 12% of the mold cross-section area (A2) of the mold component's internal surface (12).

9. A mold component according to claim 4 or 6, characterized in that said annular flow gap (4) is tapered upwards or downwards, forming an average cone angle (K) relative to the center axis (10) or being, on average, in perpendicularity to the center axis (10).

10. A mold component according to any of claims 4-9, characterized in that the number of said tangential melt feed holes (3) is not less than two.

1 1. A mold component according to any of claims 4-10, characterized in that said mold component comprises a jacket (6) and a mandrel (7), whereby

- the jacket (6) makes up the mold component's (2) lower end (2a) and the upper end (2y), and inside the jacket's upper end (2y) the mold component's elongated continuous casting mold cavity (20) extends co-directionally with the center axis (10) and opens upwards;

- said tangential melt feed holes (3) existing in said jacket (6);

- the mandrel (7) being inside or outside the mold component's (2) lower end (2a) and constitutes there a plug closing the continuous casting mold cavity (20) downward; and

- said annular flow gap (4) is between an inward face (16) of the jacket (6) and an upper face (17) of the mandrel (7).

12. A mold component according to claim 1 1 , characterized in that said mandrel (7) ex- tends:

- co-directionally with the center axis (10) from below only to the flushness with a bottom side of the flow gap (4), whereby it is a mold component (2) used in the continuous casting of a rod or a wire; or

- in the form of a core (5) co-directionally with the center axis (10) from below into an inte- rior of the mold cavity (20) to a location between its internal surfaces (12) upwards from the flow gap (4) over to a mandrel length (L), whereby it is a mold component (2) used in the continuous casting of a pipe.

13. A continuous casting method of casting a rod or wire or pipe vertically upwards, said method comprising:

- feeding molten metal (M) to a lower end (2a) of an elongated mold component (2) containing a continuous casting mold cavity (20) having a vertical center axis (10) while said lower end is submerged in the molten metal (M); - allowing the molten metal to solidify to a solid state by cooling the mold component (2) with a cooling mantle (30) which is in attachment with its upper end (2y);

- pulling the solidified, solid state metal in the form of a wire or a rod or a pipe out of the upper end (2y) of the mold component (2) at a casting velocity (V_M),

characterized in that the molten metal (M) present inside the continuous casting mold cavity (20) is set by means of one or more molten metal jets (S1 , S2), which has/have a peripheral jet velocity (V_T), in a rotating flow motion proceeding at least around the center axis (10) and having a peripheral mold velocity (V_D) which is higher than the peripheral jet velocity.

14. A continuous casting method according to claim 13, characterized in that said peripheral jet velocity (V_T) is higher than said casting velocity (V_M); and that said peripheral velocity (V_T) is at least eight times higher than said casting velocity (V_M).

15. Use of a rod, wire or pipe manufactured with a continuous casting nozzle of claim 1 or a mold component of claim 4 or a method of claim 13 as a preform in the production of a thinner and/or thinner-walled rod, wire or pipe.