DK154331B - PROCEDURE AND APPARATUS FOR LINERATED UPDATE CONTINUOUS CASTING OF A METAL STRING USING AN FORMULATING ASSEMBLY - Google Patents

Abstract

An oscillating cooled mold assembly for the continuous high-speed casting of metallic strands, (12) especially upcasting strands of copper alloys such as brass, has a hollow die (112) in fluid communication with a melt (14) typically held in a casting furnace (16). coolerbody surrounds the die in a tight-fitting relationship to form a solidification front in the melt as it advances through the casting zone of the die. During assembly, the die is preferably slip fit in the coolerbody (103). A shoulder on the die engages a lower face of the coolerbody (103) and, together with a small irregularity on the upper coolerbody wall, prevents any axial movement of the die before it thermally expands against the coolerbody. An insulating member (118) located between the die and the coolerbody and below the solidification front fixes the location of the front within a dimensionally uniform area of the die. The insulating member is preferably a ring of a material such as casting silica that has a low coefficient of thermal expansion, a low porosity, and is highly resistant to thermal shock. The insulating member (118) also preferably creates a steep longitudinal temperature gradient at its upper end to promote a high cooling rate over a relatively short casting zone. An insulating hat encloses the coolerbody, allowing it to be immersed in the melt and preferably deeply immersed to a level above the casting zone The strand or rod formed from the solidified melt is pulled through the die while the mold oscillates in a direction substantially parallel to the direction of travel of the rod.

Description

i i

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The invention relates to a method for vertical upward continuous casting of a metal strand from a metal melt / using a vertically oriented nozzle with an inlet end provided with a heat sink / surrounding a portion of the nozzle 10 to allow cooling of parts of the nozzle in which an insulating element is placed in a recess in the heat sink between part of the nozzle and part of the heat sink to insulate part of the nozzle against cooling from the heat sink, the inlet end of the nozzle being spaced 15 below the free end of the heat sink and wherein the insulating member is disposed on the free end of the heat sink and extends between the nozzle and heat sink over a predetermined distance, the free end of the heat sink being submerged in the melt to a depth 20 greater than said predetermined distance to produce a solidification front in the nozzle when the melting mass is withdrawn through said heat sink, while the nozzle is cooled through the heat sink, the cooling being brought t to completely solidify the molten metal to a strand in a portion of the nozzle over the insulating element, under which the nozzle and string alternately move back and forth relative to each other in the direction of feed of the string and an apparatus for vertically upwardly continuous casting of a metal string 30 from a metal mass for use in the practice of said method using a vertically oriented tubular nozzle vertically oriented in the apparatus of use with an inlet end in liquid communication with the melt; a heat sink with a free end surrounding a part

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2 1 of the nozzle to allow cooling of portions of the nozzle where the inlet end of the nozzle is spaced below the free end of the heat sink; an insulating member disposed in a recess in the heat sink and between a portion of the nozzle and heat sink to insulate a portion of the nozzle against the heat sink of said heat sink, said insulation member being disposed on the free end of the heat sink and extending between the nozzle and heat sink. a predetermined distance; means for immersing the free end of the heat sink in the melt to a depth greater than said predetermined distance to produce a solidification front in the nozzle below the surface of the heat sink as the melt and the solidified strand are pulled out through the heat sink; 15 means for extracting molten metal from the melt mass through the nozzle while the nozzle is cooled through the heat sink, the cooling being adapted to cause the molten metal to solidify completely to a strand in a portion of the nozzle.

20

It is common "known technique to cast indefinite lengths of metal bars from a molten mass by pulling molten metal through a chilled mold. The mold usually consists of a nozzle of heat-resistant material, such as graphite, which nozzle is cooled by a surrounding water jacket. U.S. Patent No. 3,354,936, for example, discloses a chilled mold assembly which is tightly inserted into the bottom wall of a metal melt container for molding large bars. Gravity feeds 30 the molten mass through the mold. However, when casting downwards, there is a danger that the molten mass "breaks out" and the metal melting container must then be emptied or tilted in order to repair or replace the mold or die.

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1 Horizontal casting through a chilled mold has also been used. In addition to depletion and replacement problems with the aforementioned vertical downward casting, gravity can cause uneven solidification / 5 and this results in a casting # which is not the same in cross section # or which has poor surface quality.

Finally, various appliances have been used for casting upwards. Prior apparatus is disclosed in U.S. Patent No. 2,553,921 and U.S. Patent No. 2,171,132. U.S. Patent No. 2,553,921 uses a water-cooled metallic molding tube with an outer ceramic liner which is immersed in a molten mass.

In practice, no metal has been found suitable for use as mold pipes, the cast is subjected to uneven cooling, and condensed metal vapors may collect in the opening between the mold pipe and the casing due to the difference in their coefficients of thermal expansion. In the apparatus known from the latter US patent, a water-cooled "pipe" is also used, but this is mounted over the molten mass and a vacuum is needed to pull the molten mass up into the pipe. A coaxial and heat-resistant extension of the tube extends into the molten mass. The heat-resistant or heat-resistant extension is necessary to prevent "mushroom formation", i.e. forming a solid mass of metal with a diameter greater than the chilled tube. As in the apparatus of the former US Patent No. 30, thermally developed gaps, which in this case occur between the pipe and the extension, may collect condensed metal vapors and this may result in poor surface quality or outer surfaces of the castings.

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US Patent Nos. 3,746,077 and 3,872,913 disclose a later developed upward casting technique and apparatus. According to U.S. Patent No. 3,872,913, the problems associated with the heat exchange differences are avoided by placing only the outermost tip of the "nozzle" in the molten mass. A water-cooled jacket encloses the upper end of the nozzle. Because the surface of the molten mass is below the cooling zone, a vacuum chamber 10 is required at the upper end of the nozzle to draw the molten mass up to the cooling zone. However, the use of a vacuum chamber limits the amount of string material that can be pulled up, and special fins are required for seals that can withstand the heat of the melting mass.

U.S. Patent No. 3,746,077 avoids the vacuum chamber by lowering a cooling jacket and a portion of an enclosed nozzle into the molten mass. The immersion depth 20 is sufficient for the molten mass to be fed to the solidification zone, but it is not deeply submerged.

Both the casing and the interface between the casing and the nozzle «H * are protected from the molten mass of a surrounding insulating lining. The lower end of the liner abuts the lower outer surface of the nozzle to block a direct flow of molten mass to the cooling jacket.

The aforementioned apparatus is usually characterized by a "closed" shape in that liquid metal 30 is in direct contact with the solidification front.

The cooled form is usually fed from an adjacent container which is filled with molten mass. In contrast, the molten mass in an "open" molding apparatus is usually fed directly via a supply pipe.

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1 to a form where it cools very quickly. Open molding devices are usually used for casting down large steel bars and sometimes also aluminum, copper or brass. However, the open mold casting is not used to mold products of small cross-section because it is very difficult to control the level of the molten mass and thus also the location of the solidification front.

One problem that arises from closed mold casting is the heat expansion in the bore of the mold at the beginning of solidification, the so-called "trumpet mouth.

Under such conditions, extensions of the cross-section of the casting are formed, which are wedged against a narrower portion of the die. The wedge-shaped part can be broken off to form a motionless "shell". The shells may either cause the strand to break or may remain in the die and produce surface defects on the casting. Therefore, it is important to maintain dimensional smoothness or uniformity in the nozzle bore within the molding zone.

In the apparatus of United States Patent Specification no.

No. 3,746,077 and No. 3,872,913, these problems are controlled by a relatively flat temperature gradient along the nozzle, which is partly due to a modest cooling rate 25 to generally produce a flat solidification front.

With this flat or small temperature gradient, castings of acceptable quality can be produced at a relatively low speed, usually at a speed of 13 to 100 cm per minute.

30

Another significant problem in casting through a chilled form is condensation of metal vapors. Condensation is especially troublesome when casting brass containing zinc or other alloys.

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1 containing elements which boil at temperatures below the melting temperature of the alloy. Zinc vapor readily penetrates the materials commonly used to make molds and also through the usual insulating materials, and the vapor can condense to liquid phase in critical areas. Liquid zinc on the mold near the solidification front can boil at the surface of the casting, and this can lead to a surface-conditioned defect of the gas. Because of these problems, with the current casting technique and casting, commercial production of brass strings cannot be made at high speed and with good quality.

15 It is also of great importance how the casting is drawn through the cooled mold in the molding process. A periodic process of a protruding stroke followed by a rest period is used commercially in connection with the molding unit described in U.S. Patent No. 3,872,913.

U.S. Patent No. 3,908,747 discloses a controlled return stroke to shape the casting skin, preventing the casting from being interrupted, and compensating for the shrinkage of the casting inside the mold as it cools. English patent specification 1.087026 also discloses a reversal stroke for partial re-melting of the castings. U.S. Patent No. 3,354,936 discloses a process of a relatively far-reaching stroke, followed by periods when the casting motion is stopped and reversed in a relatively short stroke. This process is used when casting down large burrs in order to prevent inverse segregation. In all these devices, however, the stroke rates and the average casting speed are very low. In the appliance 7

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For example, according to U.S. Patent No. 3,354,936, the advancing stroke is of three to twenty seconds duration, and the return stroke is of one second duration, and the average casting speed is 33 to 38 cm per 5 minutes.

It is known to oscillate a continuous mold to produce a stripping effect which facilitates the movement of the just molded rod through the die 10, and when the feed rate of the die during a portion of the period is greater than that of the rod being cast, it is very important to prevent the tension from forming cracks in the solidifying skin. Furthermore, as casting strokes occur by mold oscillations, rod 15 can be pulled out of the nozzle at a constant rate, thereby further simplifying post-casting operations, for example transforming the rod into a tape.

It is an object of the invention to provide a method for continuous casting of high quality metal strings, and in particular strands of copper and copper alloys including brass, at rates of production many times greater than those previously obtained with closed molding apparatus.

This is achieved by the method according to the invention, which is peculiar in that the solidified string is withdrawn from the melt at a constant speed and the nozzle is caused to oscillate in a direction parallel to the direction of feeding of the string, respectively, by an apparatus according to the invention. , characterized in that the apparatus has means for oscillating the nozzle in a direction parallel to 8 -

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1, the direction of advance of the string in a pattern of forward and backward blows, the means for extracting the solidified string pulling it out of the melt mass at constant speed.

5

Hereby, with a chilled mold assembly for molding upwardly with the mold assembly, oscillating and immersed in the molten mass, it is possible to produce a steep temperature gradient along a mold, in particular at the lowest end of the solidification zone, without forming shells or loss of dimensional uniformity in the molding zone. , where it is possible to produce high quality strings at unusually high speeds over the speeds known from prior art apparatus, while also providing a mold assembly which is associated with relatively low manufacturing costs which are easy to operate, and which is durable.

The subclaims disclose methods and means, respectively, the suitability of which is set out in the characterizing part of claims 1 and 7 in the following detailed description, in which the method and apparatus according to the invention are explained in more detail with reference to the drawing. , wherein FIG. 1 shows a simplified perspective view of a string making device employing methods and oscillating mold assemblies according to the invention; FIG. 2 shows a section partly from the side of the oscillating form and of the carrier con 9

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1 shows the structure according to the invention in connection with a furnace containing a molten mass; 5 FIG. 3 is a perspective view of the structure supporting the oscillating shape; FIG. 4 is a sectional view of the support manifold extension and shape of the structure of FIG. 2; FIG. 5 is an enlarged view of the heat sink and shape of the structure as shown in FIG. 4; FIG. 6 shows the heat sink of FIG. 5 in an upper plan view; 20 FIG. 7-9 show diagrams of the position of the mold in a melt at various stages of the oscillation of the mold; FIG. 10 shows a simplified vertical section where the casting furnace according to FIG. 1 is shown in its lower and upper outer positions relative to the mold assemblies; FIG. 11 and 12 show simplified vertical sections of alternate native mechanisms for controlling the expansion of the nozzle below the molding zone; FIG. 13 is a perspective view of the carriage, 10

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1 having an oscillating shape; FIG. 14 shows a separate plan view of the structure of FIG. 2 of the carriage structure 5 for supporting and moving the oscillating form # and FIG. 15 is a side elevational view of the carriage structure of FIG. 14th

10

FIG. Figure 1 shows a convenient device for continuous fabrication of metal strands of indefinite length by molding the strands upwardly through chilled molds of the present invention. Four strands 12 are simultaneously molded 15 by a melting temp residing in a casting furnace 16. The strands, which may have different cross-sectional shapes such as square or rectangular, as well as different diameters, are hereinafter described as bars, having essentially a circular cross. -20 cuts with a diameter of between 6 and 51 mm.

Referring to FIG. 1, the strings 12 are molded into four refrigerated mold assemblies 18 arranged on four vertically movable carriage structures 20.

An extractor 22 at a constant speed pulls the strands through the mold assemblies and directs them to a pair of strips 24, 24 'which guide the strings to four coil type coil wrappers 26 where the strands are assembled into coils. Each belt 24 is hollow 30 so that it can conduct cooling air supplied through the ducts 28 along the length of the belt.

The melt is prepared in one or more melting furnaces (not shown) or in a combined melting and storage 11

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1 ring oven (not shown). Although this invention is suitable for the manufacture of continuous strands made of various metals and alloys, it is particularly made for the purpose of producing strings of copper alloys, especially brass. A casting spoon 30 suspended in an overhead crane (not shown) transfers the melting mass from the furnaces to the casting furnace 16. The molding spoon is preferably of the teapot type with a spout which provides the melting mass with a minimum of foreign material such as slag and foam. To facilitate transfer, the casting spoon is pivotally placed in a cradle 32 on a casting platform 34. A ceramic spoon 36 directs the melting mass from the casting spoon 30 to the interior of the casting oven 15 16. from the mold assemblies 18. In continuous production, unlike batch molding, additional melting furnace is added when about half full to mix the melt both chemically and thermally.

The casting furnace is mounted on a scissor-type hydraulic transport trolley 38, wherein the trolley comprises a set of loading elements 38a (Fig. 10) which take up the weight of the casting furnace and its contents. Outputs from the load elements 38a are used to control the level of the furnace, and thus it is possible to automatically control the level of the molten mass 30 relative to the heat sink. As best seen in FIG.

10, the casting furnace is movable between a lower outer position where the mold assemblies 18 are above the upper level of the molten mass 14 when the casting furnace is filled, and an upper outer position (shown by 12).

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1 dotted line) / where the mold assemblies are near the bottom of the casting furnace. The height of the casting furnace is continuously adjusted during casting to maintain the selected immersion depth of the mold assemblies 18 in the melt. In the submerged position, the form assemblies for replacements or maintenance can be accessed after the vehicle is rolled out of the track.

It should be noted that the production equipment usually comprises auxiliary equipment for level control such as probes and pontoons and periodic manual measurement with a submerged wire. Oisse or other known level measurement and control systems may also be used in place of the load elements as the primary system. Although this invention has been described with reference to stationary mold assemblies and a movable casting furnace, other devices may also be used. The furnace may be kept at the same level and the molten mass may be supplied periodically or continuously to maintain the same level. Another possibility consists of a very large immersion, so that the level adjustment is not necessary. A significant advantage of the present invention is that it enables this deep immersion. Each of these devices has advantages and disadvantages which are readily apparent to those skilled in the art.

The casting furnace 16 is a 96.5 cm coreless induction furnace 30 with a stamped aluminum oxide liner heated by a power supply. An oven of this size and type can contain about 5 tons of melt. The oven 16 has a pour spout 16a which leads to a filling and pouring spoon 42 (Fig. 10).

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1 As can be seen from FIG. 1, the pull-out machine 22 has four pairs of opposite clamping rollers 44, each of which rubs against and engages one of the strings 12. The clamping rollers 44 are secured to a common shaft driven by a servo-controlled, adjustable, hydraulic motor 46. An ordinary hydraulic pump unit with adjustable volume and constant pressure, which can be up to 211 kp / cm 2, drives the motor 46. An ordinary electronic programming device 10 (not shown) produces a program of signals that controls the operation of the motor 46 through a commonly known servo system. The program includes a programmed startup phase routine that gradually sets up the draw rate. The drive rollers 44 can be disconnected individually from a selected string 12 without interrupting the feeding of the other strings.

As shown in FIG. 2, a mold assembly 18 is immersed in a melting mass 14 in a furnace 16. FIG. 2 shows 20 a protective cone 48 which melts away after the assembly 18 has been submerged in the melting mass 14. The protective cone 48 is usually made of copper and it takes less than a minute to completely melt it away. The purpose of the protective cone is to prevent foam and other contaminants from entering the nozzle 112 during immersion. When the assembly is submerged in the molten mass and the cone is dissolved, molten metal is drawn through the assembly 18. Initially, the process is initiated by introducing a massive starter rod (with a bolt at the end) through the nozzle 112 from the upper part of the assembly. in the melt. Melted metal solidifies on the bolt and as the rod is pulled through the nozzle 112, the molten metal will follow and 14 '

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1 solidify on the road. After a solidified rod or string 12 has been inserted between clamping rollers 44, the starting rod (with a small portion of the string 12) will be cut from the rest of the string 12. After 5 is formed by the melting mass 14, the string 12 is continuously pulled out at a constant velocity of one or more pairs of clamping rollers 44. In this way, the string 12 moves continuously away from the melt at a constant velocity of normally 10 51-102 cm / min. in the direction of arrow 52. As the string 12 moves forward, the entire assembly 18 swings vertically. Basically, assembly 18 is associated with e? carriage construction 20 for controlling the oscillation.

15

As the molded mold assembly 18 swings, it is cooled by means of a coolant which, through flexible tubes 56, is transferred to a manifold 54 mounted on the carriage assembly 20 20. The cooling supply system is described in detail in connection with FIGS. 3 and 4.

It is emphasized that although the manufacturing device of FIG. 1 uses four independently oscillating moldings 18 to produce four strings 12, any other number of moldings arranged one after the other may be used, depending on the particular production requirements.

As the mold assembly 18 oscillates during the molding process, large, dynamic loads are developed which must be counteracted by the load-bearing structure. The superstructure that withstands these loads with minimal deflection will now be described in detail in connection

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1 15 with FIG. 2 and 3. As can be seen first from FIG. 3, the entire supporting structure is a rigid steel box.

The vertical loads are carried by the pillar-like building elements 58/60/62 and 64 / there are steel I-beams 5. The column members 58, 60, 62 and 64 are held together by the horizontal I-beams 66, 68, 70 and 72 of steel. The horizontal members 66, 68, 70, 72 and 74 are preferably welded to the column members 58, 60, 62 and 64. The horizontal I-beams 66, 68 and 70 10 are arranged so that the faces of the flanges extend vertically to provide maximum stiffness. against the loads developed by the oscillation ring. The beams 72 and 74 are further stiffened each with angular sections 72a and 74a welded to the beams. The beams 66 15 and 70 are stiffened in a vertical direction by means of cross beams 75, 76, 78 and 80 which are also made of steel. Steel beams 82 and 84 further strengthen the structure at the bottom.

20 The carriage structure is mounted on angles 72a and 74a, which carry the carriage completely through the horizontal I-beams 72 and 74. The cargo loading paths have been advanced to the frame foundation through the beams 86, 88, 78, 80, 75 and 76. The I-beams 89 and 90 of steel, 25 is welded between the horizontal beams 68 and 72. These beams 89 and 90 carry the oscillating trolley carrying the superstructure, which in turn comprises vertical I beams 91 and 92 'and horizontal I beams 93, 94 and 95. The beams 93 and 95 are welded to the I-beam 30 74, connecting the beams 60 and 64 in the upper part thereof. The construction is made stiffer by means of the stiffening steel beams 86 and 88.

The carriage structure 20 (Fig. 2) is shown in more detail 16

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1 in FIG. 13. This structure 20 is constructed of angular plates 201 and 202 of steel and is welded to the bottom plate 203 and the back plate 205. A top plate 207 is welded to the back plate 205 and the angular plates 201 5 and 202 in the finished construction. The plates 201 and 202 # which are approximately 25 mm thick * are made lighter # with holes 209 and 210 respectively removed.

The carriage assembly 20 carries the manifold 54 (FIG. 2) # 10 with bolts passing through bolt holes 211a (FIG.

14) * which surrounds a hole 213 in the base plate 203. The hole 213 makes it possible to guide the cast string upward on its path towards the glue rollers 44 (Fig. 2).

15 Referring now to FIG. 13 and 14 # where the carriage structure is forced to move in the vertical direction on rails 215. These rails 215 are spaced apart from the angular plates 201 and 202 by intermediate or spacers 217. The rails 215 and the intermediate 20 or spacers 217 are bolted and bolted to the angular plates 201 and 202.

The rails 215 have sloping edges # which are adapted for precise engagement with inclined running rollers 219 25 (Fig. 14). The rollers 219 are bolted to the structural assembly 221. The structural assembly 221 includes the welded box structures 223 to provide increased rigidity. The structural assembly 221 is bolted to the above with reference 30 to FIG. 3 superstructure described.

Referring to FIG. 14 and 15, the carriage assembly 20 is carried for oscillation in the vertical direction by a hydraulic cylinder 225. The plunger inside the

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1 hydraulic cylinder 225 is secured to the top plate of carriage structure 20 by means of a fork 227.

The hydraulic cylinder 225 is controlled by the servo valve 229 through the manifold block 231.

5

The hydraulic cylinder 225 is itself supported by arms 233 (Fig. 14) / bolted to the structural assembly 221. Servo valve 229 is controlled by a computer (not shown) / which controls the relative movements between the rod and the mold / thus that a real solidification of the cast rod is obtained. In particular, this shape oscillation will produce the same effect as when the rod or string 12 itself is affected by a reciprocating stroke.

15

FIG. 7-9 should show the effect of the shape oscillation on the molding formation and must explain in more detail the terms "reciprocating stroke". FIG. 7 shows the mold assembly 18 at its lowest position in the melt mass 14. At this point, the mold assembly will be just about to begin its upward acceleration / as indicated by the small arrow 41. At this point, the rate of upward movement of the string will be greater than the upward or forward velocity of the mold. It should be noted that the solidification skin 12a on the string 12 is very thin. FIG. 8 shows the mold assembly 10 approximately midway in its movement up and down the molten mass. At the time / when the shape assembly has reached the center position, its velocity is greater than the velocity upward of the string. This is because the acceleration of the mold assembly in the upward direction is in most cases about 2 g. It should be emphasized again that the speed of the string is constant.

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1 and that only the speed of the shape assembly varies. In FIG. 8, a solidification front 29 has moved close to the top of the molten mass. The skin 12a has become thicker compared to the skin of FIG.

5 7.

FIG. 9 shows the shape at the top of its runway. At the particular moment shown in FIG. 9, the mold speed in upward or forward direction 10 is zero and is just about to begin the trip back and down to that of FIG. 7. The solidification skin 12a is at its thickest in this position. The forward and backward speeds are separately adjustable in the computer to achieve the best possible surface quality and material structure. Seen on the basis of FIG. 7-9, it should be obvious that the term "forward stroke" refers to the movement of the mold assembly away from the molten mass, while the term "backward stroke" indicates the movement of the mold assembly further into the molten mass.

FIG. 4 and 5 show a preferred embodiment of the mold assembly 18 and indicate how refrigerant 25 is continuously fed thereto. Refrigerant, preferably water, is introduced into the manifold 54 at an inlet 100 and runs downwardly through an annular channel 101 in a manifold extension assembly 102 and continues into a heat sink 103 for cooling a mold 304. The refrigerant returns through an annular channel 105 and out. of the outlet 106. The ducts 101 and 105 consist of the annular spaces defined by three concentric tubes 107, 108 and 109, all of steel. The outer tube 107 is connected by a flange «19

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1 with the manifold 54. The two inner tubes 108 and 109 slip into the O-ring stop bushes 110 in the manifold 54. In this design, dimensional changes caused by rising temperatures are accommodated.

5

The concentric tube pattern of the manifold extension assembly 102 allows high flow rates of the refrigerant in association with a reduction of the cross-sectional surface of the assembly which must oscillate in the melting mass of the casting furnace. It is important to reduce the cross-sectional surface to limit the hydrodynamic load on the oscillating mold assembly.

Referring now to the detailed FIG. 5, wherein a tubular nozzle 112 is enclosed by the heat sink 103. The nozzle 112 has a lower end portion 112a extending beyond the lower surface 103a of the heat sink.

The nozzle end portion 112a and at least a portion of the heat sink is immersed in the melting mass 14 during the casting process. Cuprostatic pressure forces the liquid melt into the nozzle in the direction of the heat sink.

In the initial phase, a length of straight rod is introduced into the nozzle through a graphite pin and placed with its lower end, normally connected to a bolt, slightly above a normal solidification or casting zone 114. The immersion depth is selected in such a way that the liquid melt mass when the casting zone 114, where the melting mass, due to rapid heat transfer from the melting mass to the heat sink, solidifies to form a solid casting without running past the starting rod.

The melting mass closest to the nozzle cools faster than the centrally located melting mass, so that an annular "skin" is formed around a liquid core. The interface between liquid and solid 20

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1 mass forms a solidification front 114a across the casting zone 114. It is convenient that the top of the solidification front. 114a is always below the surface of the melt 14. Since the solidification is initiated in the 5 part of the nozzle 112, which is lined on the back with an insulating sleeve 118, the location of the solidification front is well defined. It is a feature of the invention that the molding zone is characterized by a high cooling rate and a steep vertical temperature gradient 10 at the lower end such that the zone extends over a relatively small length of the nozzle 112. These features result from the solidification of the melting mass. is initiated in the region of the nozzle equipped with the insulating blank or bush 118.

15

The nozzle 112 is formed of a refractory material which does not substantially react with the metal vapors and other vapors present in the molding region, especially at temperatures above 109 ° C. The normally used material for the nozzle is graphite, but good results have also been obtained with boron nitride. In particular, a graphite marketed by the Oco Graphite Company under the trademark DFP-3 has shown exceptionally good thermal properties and durability. Regardless of the choice of material 25 for the nozzle, it is preferred that ... prior to installation be poured into a vacuum furnace to remove volatiles which may react with the melt and cause initial failure or produce surface defects during the molding process. The ambient vacuum also prevents oxidation of the graphite at the high outgassing temperatures, e.g. At 90 ° C for 90 minutes in a coarse pump vacuum. It will be appreciated by those skilled in the art that the other components of the mold assembly must also be liberated from volatile liquids, especially water, before '21

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1 the application. Components made from the refractory "Fiberfrax" (Carborundom Co.'s trade name for refractory aluminum silica paper) are pre-heated by heating to about 815 ° C, while other components, e.g. those formed of silica are usually heated to 177-204 ° C.

The nozzle 112 is usually tubular with a uniform inner bore diameter and a substantially uniform wall thickness. The inner surface of the nozzle is very smooth, so that a low frictional resistance to the axial or longitudinal casting movement through the nozzle reduces wear. The outer surface of the nozzle, which is also smooth, is in contact with the surrounding inner surface 103b of the heat sink 103 during pressure. The surface 103b inhibits the radial expansion of the nozzle due to the heat effect of the melt and casting and promotes a very efficient commodity transfer from the nozzle to the heat sink as a result of the resulting pressure contact.

The fit between the nozzle and the heat sink is important since a poor fit that leaves openings greatly limits the heat transfer from the nozzle to the heat sink. A tight fit is also important to prevent the longitudinal movement of the nozzle relative to the heat sink due to the friction or "drag action" between the cast and the nozzle as the cast is pulled through the nozzle. On the other hand, the nozzle must be able to move quickly and conveniently from the heat sink if it is damaged or worn. It has been found that all these objectives have been achieved by working with each other 22

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1 flush surfaces of the nozzle and heat sink for tight tolerances allowing a "slip fit", i.e. an axially directed sliding insertion and removal of the nozzle. The dimensions for forming the nozzle and the corresponding surface 103b are selected in such a way that the thermal expansion of the nozzle during the molding process forms a tight fit. Although the material of the nozzle usually has a much lower thermal expansion coefficient (5 x 10 6 "6 in./in.°P) than the heat sink 10 (10 x 10" 6 in./in.°F), the nozzle is much hotter than the heat sink. The average temperature of the die in the molding zone through the wall thickness is assumed to be about 538 ° C at a melting temperature of 1093 ° C. The heat sink has approximately the same temperature, usually 27-38 ° C such as the flowing refrigerant.

Mechanical forcing is used to hold the nozzle in the heat sink during low speed operation or during installation before the nozzle is thermally expanded by the melt. A single locking blank such as a screw or locking plate has proved to be impractical because the blank is cooled by the heat sink and therefore condenses and collects 25 metal fumes. Such metal depots can create surface defects in the cast and / or weld the locking member in its position, which will greatly prevent the replacement of the nozzle. In particular, the presence of zinc vapors in a brass casting process is particularly troublesome.

A possible solution is to place a small projection or elevation 103c on the inner surface 103b of the heat sink, for example, by retracting a grat with a diving nail. A small pin 116 formed on the outer surface of the nozzle that engages the lower body of the heat sink

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23 1 surface 103a (or more precisely against an "outside" insulating sleeve or ring 118 disposed in a protrusion 103d formed at the lower end of the heat sink) detects the nozzle for alignment and will further counteract any, irregular and strong forces that may occur, for example, in the initial phase.

It is also noted that by constructing the nozzle in one piece, joints are avoided, in particular joints between different materials, which can collect 10 condensed vapors or direct them to other surface portions. Furthermore, a single-piece nozzle can also be more easily replaced and retained than a multi-section nozzle.

Other possible devices for establishing an appropriate tightly matched connection between the nozzle and the heat sink may be referred to as ordinary pre-fit or thermal fit. In a press fit, a lubricant of molybdenum sulfide is used on the exterior surface to reduce the possibility of fracture of the heat sink during the press fit process. In addition, the lubricant will fill machining scratches in the nozzle. In the thermal fit, the heat sink is expanded by heating, the nozzle is inserted and the tight fitting established as the assembly cools. However, both the press fit and the thermal fit require that the entire mold assembly 18 be moved from the cooling water manifold in order for a nozzle to be replaced. Obviously, this is more time-consuming, inconvenient and costly than the easy care.

Although the preferred embodiment of the invention employs a one-piece nozzle with a uniform drill diameter, it is also possible to use a nozzle with 24

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1 shows a tapered or stepwise inner surface which narrows in the upward direction, or a multi-section nozzle formed of two or more pieces mounted end to end. It is desirable to have a constriction upward to equalize the contraction of the cast during cooling. Close contact with the cast over the full length of the nozzle increases the cooling effect of the mold assembly. Increased cooling is important because it helps prevent formation of a central cavity caused by an uncompensated shrinkage of the molten center of the mold.

In order to reduce the cost, the nozzle can be made with an opposing ion on the outer surface 15 rather than on the inner surface of the nozzle, or on the internal surface 103b of the heat sink.

The thermal expansion of the nozzle in the heat sink during casting produces the desired upwardly tapered shape of the very smooth inner surface of the nozzle. Nozzles in more than 20 sections may have either the same drill diameter or different drill diameters to produce a stepwise upward narrowing. To avoid difficult metal deposits between the parts of the nozzle, the joints between the sections should only be above the casting zone. Furthermore, the upper section or sections above the casting zone may be press fit fitted as it is most likely that the lower section will be damaged and must be replaced.

For clarification, mention may be made, for example, of a nozzle formed in one piece of graphite of the so-called Poco type, which nozzle is suitable for casting 19 mm rod material and has a length of approx. 273 mm and a uniform wall thickness of approx. 3-5 mm. Wall thickness 25

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The molding will generally vary with the diameter of the molding. The projecting part of the nozzle 112a / usually has a length of 51 mm.

The heat sink 103 is substantially cylindrical with a longitudinal center aperture defined by the inner surface 103b. The interior of the heat sink has a channel, generally designated 120, which circulates the coolant, preferably water, through the heat sink. At the upper end of the heat sink, a plurality of inlet openings 120a and outlet openings 120b are arranged to the cooling water. As best seen in FIG. 6, er. these apertures arranged in concentric circles with sufficient apertures to provide a large amount of flow, usually approx.

8.3 liters per liter kg casting per minute. A pair of O-rings 122 and 123, preferably formed of durable fluorine elastomers, seal the manifold extension assembly 102 (see Fig. 5) in liquid communication with the inlet and outlet openings. A mounting flange 124 on the heat sink has openings 124a which receive the bolts (not shown) for securing the mold assembly to the manifold extension assembly. This flange also includes a hole (not shown) for discharging gases from the annular space between the heat sink and an insulating cap (see Figure 4) through a tube (not shown) in the manifold 54 to the atmosphere.

The heat sink consists of four main components: an inner body 126, an outer body 128, a sheath closure 30 130, and the mounting flange 124. The inner body is formed of an alloy that has excellent heat transfer properties, good dimensional stability, and is hard and durable. An age-cured copper such as e.g. the alloy designated by CDA 182.

26

DK 154331 B

The outer body 128, the closure ring 130 and the mounting flange 124 are preferably formed of stainless steel and in particular "free machining" 303 stainless to the ring 130 and the flange 124, and 304 stainless to the outer body 128. Stainless steel is sufficiently resistant to mechanical loads that have similar thermal expansion properties as chrome copper and are very resistant to the cast environment. By using stainless steel, the use of very large pieces of age-cured copper is made superfluous, thereby simplifying the production of the heat sink.

The inner body is made of a single cylindrical bar of whole (fracture-free) chrome copper. In addition to the cost and reliability advantages, the composite heat sink assembly is determined by the difficulty of producing an entire bar of chrome copper large enough to form the entire heat sink. Longitudinal holes 120c are drilled 20 deep into the inner body to form the inlets 120a.

The holes 120c extend at least to the molding zone and preferably somewhat longer, as shown in FIG. 5. Transverse holes 120d are drilled into the bottom of the longitudinal holes 120c. The upper and lower ends 25 of the inner body are threaded at 126a and 126b so that they can receive the mounting flange 124 and the closure ring 130, respectively, to strengthen the structure. The closure has an internal upward recess 130a adjacent to a corresponding step disposed on the inner body to increase the strength of the solder joint, to slow the flow of cooling water into the joint and to align the ring with the inner body. . An outer upward recess 130b is in liquid-tight connection with 27

DK 154331 B

1 shows the lower end of the outer body 128.

Since the thread assembly at 126b will leak / if it is not closed tightly to / and be able to withstand the dissolution and aging process of softened heat sink bores, the joint is also copper / gold brazed.

Although copper / gold soldering is a generally known technique, the following method provides a reliable joining / that will exist in the casting environment. First, the corresponding surfaces of the closure ring and the inner body are copper plated. The sheet lining is preferably 0/025 to 0/051 mm thick and should also include the threads, recess 130a and groove 130c. Then, the solder is applied by wrapping a thread of the material around the inner body in a solder groove 126c above the threads and in the groove 130c on the closing ring 130. Two coils with a thread consisting of sixty percent copper and forty percent are recommended. gold with a diameter of 1.59 mm in the solder groove 126c 20 and three turns in the groove 130c. A solder paste of the same alloy is then applied to the corresponding surfaces. The closure is screwed tightly to the inner body, and the assembly is placed in an oven with the brazed end facing downward and preferably resting on a support layer of refractory aluminum silica paper material, for example the aforementioned Fiber Fraction. The brazing temperature is measured by a thermocouple · Which rests on the bottom of one of the longitudinal holes 120c. The furnace heats the assembly to a temperature η which is just below the solder alloy melting point for a shorter period of time, for example to between 960 and 977 ° C for 10 minutes. The atmosphere in the oven is protected (inert or vacuum) to prevent oxidation, and then quickly warmed to a 28

DK 154331 B

1 temperature which liquefies the solder alloy (1016-1038 ° C) and is immediately cooled to room temperature, also this time in a protected atmosphere. Solution treatment of chromium copper is best accomplished at a separate second step in the process by heating the portion to 932-954 ° C for 15 minutes in a protected atmosphere with a subsequent rapid liquid cooling.

After the closure ring is connected to the inner body, the remaining assembly of the stainless steel TIG welding heat sink comprises type 304 to type 303 using rod type 308 after the parts are preheated to 204 ° C. The largely cylindrical outer body is welded to the closure ring at 134. The upper end of the outer body has an internal recess 128a which fits the mounting flange 124 just outside the water outlet openings 120b. A weld 136 joins these parts together. The closure ring and the mounting flange position the outer body at a distance from the inner body, so as to define an annular water circulating channel 120e extending between the transverse holes 12Od and the outlet openings 120b. A helical spacer sleeve 138 is secured to channel 120e to form a swirling stream of water which will promote a more uniform and efficient heat transfer to the water. The spacer sleeve is preferably formed of a 6.35 mm copper rod. The bushing tube is flattened at points 138a to allow for locking clips 140 attached to the inner body. A combined aging (curing) treatment of chromium copper and stress relief of the welded stainless steel is carried out at a temperature of 482 ° C for at least two hours in a protective coating.

DK 154331 B

1 dense atmosphere. The heat sink is then machined and leak tested.

For the sake of clarity only one example is mentioned, in which cooling water is passed through the inlets 120a, the holes 120c and 120d and the helical flow path defined by the channel 120e and the spacer sleeve 138 to the outlets 120b. The water usually has a temperature of 26.6 ° -32.2 ° C at the inlet and is usually heated at 3.30-6.6 ° C during its circulation through the heat sink.

The water usually flows at an amount of approx. 8.3 liters per liter. kg of solidified strand in the casting zone; minute.

A normal flow rate is 95 liters per liter. minute.

The correct water temperature is limited at the lower end by condensation of water vapor. On humid days, condensation may occur at 21 ° C or lower, but usually not at temperatures above 27 ° C. Water temperatures exceeding 49 ° C are usually not preferred. It should be noted that the inlet 20 and the outlet holes can be reversed; i.e. the water can be fed to the outer ring with holes 120b and drawn from the inner ring with holes 120a without any significant reduction in the cooling capacity of the heat sink. However, the distance between the nozzle and the interior set of holes is a factor affecting the efficiency of the heat transfer from the cast to the water. For a 19 mm string 12 the distance is usually approx. 16 mm.

This makes it possible to drill the inner body 126 to mold a 25 mm strand and receive an appropriately sized outer insulator 118.

In general, the aforementioned mold assembly will provide a cooling rate which is high in comparison with the commonly known water jacket coolers for mold-molded molding in closed systems.

30

DK 154331 B

Another important feature of the present invention is the external insulating sleeve 118 which ensures that the nozzle is dimensionally uniform in the casting zone and prevents an exceptionally large outward extension 5 (trumpet mouth) of the nozzle below the zone which may cause interruptions in the casting, starting difficulties or surface defects. . The sleeve 118 is also important in that it creates a steep axial temperature gradient in the nozzle immediately below the casting zone. Without the sleeve 10 118, e.g. be a sharp temperature gradient at the nozzle entrance to the heat sink, which would cause the lower portion 112a of the nozzle to form a trumpet-shaped molding head. The extended piece cannot be pulled past the casting zone into the heat sink.

15 It is stuck, breaks away from the casting and can remain in place as the casting continues. Such a wedged piece may cause poor surface quality or string breakage. The sleeve 118 alleviates this problem by mechanically limiting the outside expansion of the nozzle immediately below the casting zone 114. It also greatly insulates the nozzle against the heat sink and creates a gentle thermal gradient in the nozzle over the area extending from the lower heat sink surface 103a to somewhat below the lower edge 25 of the molding zone 114.

The sleeve 118 is formed of a refractory material which has a relatively low heat expansion coefficient, a relatively low porosity and a good heat shock resistance. The low heat expansion coefficient limits the outward radial pressure from the sleeve to the heat sink and, together with the heat sink, will force the graphite to maintain a substantially uniform internal diameter in the nozzle. The low heat expansion coefficient 31

DK 154331 B

1 also allows the sleeve 118 to be easily removed from the heat sink by uniformly heating the assembly to 120 ° C. A suitable material for the bushing is cast silica glass (S1O2) / which can be machined with the machines.

The sleeve 118 extends vertically from a lower end surface 118a that aligns with the lower surface 103a of the heat sink and an upper end surface 118b 10 slightly above the lower edge of the molding zone. In the manufacture of a 19 mm brass rod has a bushing having a wall thickness of approx. 6.4 mm and a length of 35 mm yielded satisfactory results.

In practice, it has been found that metal vapors penetrate between the outer insulating sleeve 118 and the heat sink's shoulder bore 103d, continuing and securing the ring to the heat sink, making it difficult to disassemble. A thin interlayer of 20 steel foil 142 disposed between the ring and the shoulder bore solves this problem. The sleeve and the intermediate layer are held in the shoulder bore by means of a special thermal fit, i.e. a fitting that facilitates assembly and disassembly as the bushing and heat sink are heated to 204 ° C.

Pig. 11 and 12 show alternative devices which will ensure that the casting takes place in a dimensionally uniform portion of the die and which can control the expansion of the die 30 below the die zone. Pig. 11 shows a nozzle 112 'which is identical to the nozzle 112 with the exception that the portion 112a projecting below has a tip formed on the inner surface which extends upwardly. The taper is 32

DK 154331 B

1 so selected that a substantially uniform bore diameter is obtained as the nozzle portion expands into the melt. However, this solution is difficult to manufacture. Nevertheless, in practice, it is necessary to use the sleeve 118 (shown in dotted line) as well as the nozzle 112 'to achieve the high production rates and good casting characteristics characteristic of this invention.

FIG. 12 shows the "inside" of insulator 144 slidingly inserted into a nozzle 112 "identical to the nozzle 112 except that it ends in flight with the heat sink surface 103a. The inner insulator 144 is formed of refractory material which does not react with the molten metal and has a relatively low thermal expansion so that it will not deform the heat sink. The lower end of the insulator 144 extends slightly beyond the lower end of the nozzle 112 "and heat sink as it "Has an extended outer diameter of 20 meters forming a pin 144 'having a function similar to the pin 116 of the nozzle 112. The upper end should be positioned near the lower end of the molding zone, usually approx. 13 mm below the top of the sleeve 118.

If the upper end extends too high relative to the outer insulator, the strand will be molded against the insulator, leaving indentations in the strand. The drilling dimensions of the internal insulator are also important, especially during the start-up phase, during a break or at reduced speed, because the melting mass starts to solidify on the internal insulator 144. In order to avoid interruptions in the casting, the inner surface of the insulator 144 must be smooth and tapered with upward expansion. As with the nozzle 112 *, the external insulator or sleeve 118 is used in connection 33

DK 154331 B

1 with the internal insulator 144 to reduce the aforementioned difficulties.

As further shown in FIG. 4, a ceramic cap 146 surrounds the heat sink 103 and manifold extension assembly 102 to thermally insulate them against the molten metal mass / so that the heat sink can perform its cooling function of the mold so that the rod can solidify. The cap 146 is formed of a suitable refractory material, e.g. cast silica.

The cap 146 is attached to the manifold 54 by means of a ring 148 which is spring loaded against the manifold 54 by a spring 149. Due to this fastening method of the cap 146, it is tightly tightened against the heat sink 15 103 while compensating for changes due to different thermal expansion.

The spring 149 is preloaded to produce a total force greater than the largest G load that can occur during oscillation, thereby providing good sealing between the cap 146 and the cooler 103. The cap allows a dip of the mold joint - the position in the melt to any preselected depth. Although immersion to a level below the casting zone is convenient, the extremely high production rate characteristic of the invention is, in part, a result of a relatively deep immersion, at least to the level of: the casting zone.

An advantage of this deep immersion is that it facilitates the application of the melt to the liquid core 30 in the cast in the casting zone.

A steam shield 150 and gaskets 151 (see also FIG.

5) is positioned in the gap between the cap and heat sink so that they adjoin the nozzle to prevent the melt mass 34

DK 154331 B

1 and the vapors in entering the slit and to further heat insulate the heat sink. The gaskets are preferably three or four annular layers or "vanilla wreath" of the aforementioned refractory Fiberfrax fiber material, while the vapor shield preferably consists of a "vanilla wreath" of molydene foil interposed between the seals 151. The shield 150 and the seals 151 extend from nozzle extension 112a to the outer circumferential surface of the heat sink. The overall thickness, usually 10 6.4 mm, is sufficient for these layers to engage firmly with the heat sink surface 103a and the end surface of the cap 146.

In a typical operation, the casting furnace 16 is filled with 15 a molten alloy. A rigid stainless steel rod is used to start the casting. A steel bolt is screwed into the lower end of the rod. The rod has the same dimensions as the rod to be cast, e.g. a rod having a diameter of 19 mm, so that the rod 20 can be passed down through the mold assembly and can engage the extracting machine 22.

When the mold assembly is immersed in the melt, a cone of a material, preferably solid graphite that does not contaminate the mass to be cast, covers the nozzle end 112a (or a refractory nozzle extension such as the internal insulator 144). A further alloy cone 48 of a material, normally copper which does not contaminate the melt, 30 covers the lower end of the cap 146. The cones pierce the slag and foam on the surface of the melt, thereby reducing the number of foreign particles trapped under the heat sink and in the nozzle. The melt dissolves the cone 48 and the starting rod bolt 35

DK 154331 B

1 pushes the smallest graphite cone away from the nozzle and then floats aside. An advantage of the preferred embodiment of the invention, where a protruding piece 112a is used in the die, is that it supports and puts the smallest graphite cone%> when it is immersed in the melt. To function satisfactorily, the 48 surface of the largest cone should form an angle of forty-five degrees or less with the vertical plane.

10

After the graphite cone has been pushed away, the bolt extends into the melt and the melt solidifies on the bolt. In the initial phase and after the strings have moved sufficiently far above the drive wheels 44, the cast rod is cut off under the steel bolt and the strands are automatically diverted to the belts 24, 24 '.

Before placing the starter rods in a storage rack for later use, remove the short piece of cast length and the steel bolt. In another aid forming 20 of the starting rod, a short piece is used for a stainless steel rigid rod which is attached to a flexible cable that can be mounted directly onto the ribbon 24 because of its flexibility. The extractor is then started up to a speed at which the molding process 25 can begin. Between shifts and during temporary interruptions, such as when replacing a coil, the string is stopped and pinched. The casting is simply resumed by loosening the string and starting up to full speed.

30

During the stretching of the string 12, forward striking pulls the solidified mold formed in the casting or solidification zone upwards, thereby bringing the melt mass into contact with the cooled nozzle which rapidly 36

DK 154331 B

1 forms a skin on the newly exposed nozzle surface. At a steady workflow, the bar is pulled at a constant speed of from 508 to 1016 cm per minute. At the same time, the entire mold assembly, including the encapsulated nozzle 112, oscillates in a vertical direction with an acceleration of approx. 1 g, thereby achieving a top speed of approx. 10 cm per second in each direction. The oscillation ring makes the skin stronger and attaches it to the previously formed cast. Due to the high cooling capacity of the heat sink and the steep temperature gradient produced by the external insulator 118, solidification takes place very quickly over a relatively short portion of the nozzle. As previously mentioned, the normal melting temperatures for oxygen-free copper and copper alloys are approx. 1038-1260 ° C. In the practice of the present invention, the insulator (sleeve 118) isolates the melt from the heat sink to maintain the liquid in the nozzle below the molding zone. Near the upper edge of the insulator, the temperature of the melt decreases rapidly and solidification begins. When casting a 19 mm brass rod at a speed of more than 254 cm / min. the casting zone will extend in the longitudinal direction to a length of 25-38 mm. At the top of the casting zone, the string 25 is solidified. The estimated average temperature for brass castings in the solidification zone is about 900-955 ° C.

A normal temperature of the brass molding as it exits the mold assembly is 816 ° C. At the upper end of the mold assembly, there is a gap 30 around the string to ensure the presence of oxygen or water-saturated atmosphere for burning zinc vapors before condensing and flowing down to the molding zone. The string produced in this way is of an exceptionally good quality. The string is known 37

DK 154331 B

1 characterized by a fine grain size and dendrite structure, good tensile strength and good flexibility.

The invention is further illustrated by the following example.

Using the device shown in FIG. 2 in the drawing, a string 12 was continuously molded from a free-cutting ibrass CDA 10 360. 1998 kg of molten alloy was charged to the furnace 16 and kept in the molten state. The composition of the alloy CDA 360 is:

Metal Weight Percent 15 Lead 2.5-3.7

Copper 60.0 - 63.0

Iron 0 - 0.35

Impurities 0 - 0.5

Zinc balance 20 '3 *

After the casting of a string 12 is initiated by inserting a tube with a screw at the end through the nozzle 112 into the melt, followed by an extension of the tube in the manner known in the art,

Zd ....

For example, the solidified strand 12 was pulled from the rollers 44 at a rate of 508 cm per minute. Wet the beginning of the continuous extraction of the string 12, the body 18 of the oscillating form was immersed in the melt-2Q mass to a depth of approx. 13 cm. During casting, the immersion depth of the body 18 varied from approx. 18 cm to 8 cm. During the oscillation of the mold, the temperature of the melt mass was maintained at 1010 ° C and molten alloy was fed to furnace 16 during the sealing as necessary to maintain the immersion temperature.

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38 at the depth of the body 18. The diameter of the nozzle was 19 mm to produce the string 12 with a diameter of approx. 19 mm. The speed of movement of the mold back and forth during the oscillation reached a maximum of 5 10 cm per second at the acceleration of the mold of 1 g.

The distance traveled by the mold between its upper and lower positions in the melt was approx.

4.5 cm. The temperature of the string 12 as it left the mold 112 was approx. 816 ° C.

10

After casting, the rod was heat treated with satisfactory results. The cast grain size was pillar-like and 1 mm. The machined structure was finely crystallized throughout the cross section (0.025 15 - 0.050 mm).

20 25 30

Claims (10)

39 DK 154331 B A method of vertically upwardly continuous casting a metal strand (12) from a metal melting mass (14) / using a vertically oriented nozzle (112) having an inlet end (112a) provided with a heat sink (103) / which having a free end surrounds a portion of the nozzle (112) to allow cooling of portions of the nozzle (112) / wherein an insulating element 10 (118) is arranged in a recess in the heat sink (103) between a portion of the nozzle (112) and a portion of the heat sink (103) for insulating a portion of the nozzle (112) against cooling from the heat sink (103) / the inlet end (112a) of the nozzle (112) being spaced below the free end # of the heat sink 15 (103). the insulating element (118) being disposed on the free end of the heat sink (103) and extending between the nozzle (112) and the heat sink (-103) over a predetermined distance / the free end of the heat sink (103) being submerged in the melt (14) 20 to a depth greater than said predetermined distance to produce a solidification rim (114a) in the nozzle (112) as the melt (14) is withdrawn through said heat sink (103), while the nozzle (112;) is cooled through the heat sink (103), causing cooling to completely solidify the molten metal to a strand (12) in a portion of the nozzle (112) over the insulating element (118) / under which the nozzle (112) and the string (12) alternately move back and forth in relation to each other in the direction of advance of the string (12), characterized in that the solidified string (12) ) is withdrawn from the melt (14) at a constant rate and caused the nozzle (112) to oscillate in a direction parallel to the direction of feed (12). 40 DK 154331 B 1 PATENT REQUIREMENT A method according to claim 1, characterized in that a coolant is circulated through the heat sink (103) to a point immediately above the upper edge of the insulating element (118) to initiate the solidification of the melt mass (14) into a string (12). the part of the nozzle (112) covered by the insulating element (118) and to completely solidify the melt (14) to a strand (12) in a portion of the nozzle (112) located above the insulating element 10 (118) . Method according to claim 3, characterized in that the part of the heat sink (103) immersed in the melt (14) is protected from the heat 15 from the melt (14) by an insulating material placed as an insulating barrier between the melt (14) and the heat sink (103). Method according to claim 1, characterized in that the string (12) is withdrawn from the nozzle (112) at an extraction speed of 508-1016 cm per minute. minute. Method according to claim 1, characterized in that the nozzle (112) is oscillated with an acceleration of approx. 1 g in each direction to achieve a maximum rate of approx. 10 cm per second. Method according to claim 5, characterized in that the nozzle (112) is allowed to oscillate at a frequency of 12-150 periods per second. minute. Apparatus for vertical upward continuous casting of a metal strand (12) from a metal melting mass (14) for use in the method of claim 1 using a vertically oriented tubular nozzle (1Γ2) in the operating position of the apparatus with an inlet end (112a) in liquid communication with the melt (14); a heat sink (103) having a free end (103a) / 5 surrounding a portion of the nozzle (112) to allow cooling of portions of the nozzle (112) / whose inlet end of the nozzle (112) is spaced below the heat sink (103) free end (103a); an insulating element (118) located in a recess in the heat sink 10 (103) and between a portion of the nozzle (112) and the heat sink (103) to insulate a portion of the nozzle (112) against the cooling of the heat sink (103) / said insulating element (118) being disposed on the free end (103a) of the heat sink (103) and extending between the nozzle (112) and the heat sink (103) over a predetermined distance; means (20) for immersing the free end of the heat sink (103) in the melt (14) to a depth greater than said predetermined distance to produce a solidification front (114a) in the nozzle (112) below the melt mass (14) surface / when the melt (14) and the solidified string are pulled out through the heat sink (103); means (44) for extracting molten metal from the melt (14) through the nozzle (112), while the nozzle is cooled through the heat sink (103), the cooling being arranged to enable the molten metal to solidify completely to a strand (12). ) in a portion of the nozzle (112) / characterized by means (225) for being able to oscillate the nozzle (112) in a direction parallel to the direction of advance of the string 30 (12) in a pattern of forward and backward blows / the means (44) for extracting the solidified strand (12) pulls it out of the melt mass (14) at a constant speed. DK 154331 B 42 Apparatus according to claim 7, characterized in that the apparatus comprises means for allowing a coolant to circulate through the heat sink (103) to a point immediately above the top of the insulating element (118) to initiate the solidification of the melt mass (14) to a string (12). ) in the portion of the nozzle (112) covered by the insulating element (118) and to completely solidify the melt (14) to a strand (12) in a portion of the nozzle (112) over the insulating element 10 (118). Apparatus according to claim 8, characterized in that the apparatus comprises means for continuously being able to control the height of the melt (14) in relation to 15 of the heat sink (103). Apparatus according to claim 9, characterized in that the means for controlling the height of the melt mass (14) is a lifting mechanism (38) arranged to be raised and lowered in response to a signal transmitted in connection with the melt mass ( 14) weight. 25 30