ES2298322T3 - APPARATUS FOR PRODUCING LINGOTS OF NON-FERROUS METALS BY CONTINUOUS FOUNDRY - Google Patents

Abstract

An apparatus for producing ingots of nonferrous metals, comprising a continuous casting machine (2) provided with a moving casting shell composed of a plurality of segments (3) arranged in succession, each segment having a portion, with bottom (3a) and side walls (3b,3c), of the casting shell formed therein and being open on the sides directed toward the contiguous segments. The segments are movable along a closed path that has at least one substantially straight portion at the casting region. The segments, along the at least one portion (4) of path, are substantially aligned and form a casting shell that is continuous and substantially straight and is closed, along at least one portion of path downstream of the casting region, by closure means at its side that is arranged opposite with respect to the bottom. <IMAGE>

Description

Apparatus for producing non-metal ingots Ferrous by continuous casting.

The present invention relates to an apparatus to produce non-ferrous metal ingots by casting keep going.

In general, all metals are extracted at from mined minerals or are obtained by recycling scrap and, after many stages of pyrometallic refinement and / or electrolysis, are provided in a commercial form, that is, reduced to appropriate sizes. These forms, depending on their type, they have several names, such as bars for wire rod, square section bars, T bars, first fusion ingots or ingots, and the metals that constitute them can be pure or be alloys

The present invention relates to the type of ingot, that is, to the appropriate "manual" format to hit it melt and have a weight between 1 and 25 for example kilograms

Ingots are required, according to your use, in various dimensions in terms of cross section and by Therefore, they must have characteristics that ensure the desired quality of molten metal.

As an example, the characteristics of Some ingots are cited below:

- primary aluminum ingots (obtained by electrolysis): weight 10-25 kilograms, length approximately 650-750 mm;

- aluminum alloy ingots (from scrap metal): weight 5-10 kg, length approximately 350-750 mm;

- brass ingots: weight 10-15 kilos, length approximately 450-550 mm;

- zinc alloy ingots for emptying pressure: weight 1-5kg, length approximately 400-600 mm

The cross sections and lengths of The ingots are the most suitable for later storage And sent. In general, ingots are stacked to get packages which are convenient for transport, which generally weigh between 500 and 1000 kg.

Packages or batteries are tied and held together by two or more ligatures provided by bands Made in metal or plastic.

Currently, the production procedures of Most common ingots are as follows:

- procedure A: casting in housings open, which are filled one by one and placed on a tape conveyor or on a wheel that has a vertical axis (such as a Walter wheel);

- procedure B: continuous casting through of housings (chilled collars) that are fixed or oscillate and are vertical and horizontal, to obtain bars that have a generally rectangular cross section with borders rounded, which are then cut to size using a cutting head with a rotating blade;

- procedure C: continuous casting on a machine of the type of wheel and belt, for example of the type described in US patent application 08 / 245,404 in the name thereof applicant, which produces a continuous bar that has a section trapezoidal transverse which is then cut to size using shears online.

These production procedures have problems and inconveniences

In the case of procedure A, the discharge Discontinuous metal is made individually, housing a housing, also due to the high speeds required, has never Achieved the sought reliability. Housing filling is never constant, therefore, produces heights of variable ingots, with the consequent problems in the stacking of the ingots.

In addition, the upper ingot surface that it is exposed to the atmosphere and to the turbulence of the discharge oxidizes a lot and contains impurities and scum inclusions that float on molten metal during solidification.

This phenomenon has been solved only from partial way with more or less automated foaming operations  (a process that is always incomplete and unsatisfactory) and produces losses of metal in the foam that the subsequent fusion of ingots

In addition, with this procedure can occur cracks and cavities during solidification, which is slow, It produces a rough grain and generates concentrated gas. This is a serious danger, since any infiltration of rainwater in the cracks or cavities can cause a powerful explosion when Ingot is immersed in a molten metal bath where the additional fusion

Finally, again with this procedure, the ingot dimensions are highly correlated with the dimensions of the housing, and changing them is very expensive.

Regarding procedure B, the system of foundry is very structurally complicated and in terms of its direction, since to achieve convenient production levels industrially it is necessary to place in parallel (one next on the other) many foundry lines that have to work from simultaneously. The cooling and solidification housing, when be a necklace (semi-oval or rectangular with rounded edges) which cools with water and has a limited length (approximately 200-400 mm), has a surface of very small heat exchange, and this causes some low solidification rates and therefore a low production per hour.

In addition, the cutting of the ingots, in addition to require a very complicated scrollable disk cutter, generates a large number of chips, which must first be collected and then return to the oven to melt again.

The ingot had with this procedure has a rough surface that can trap moisture and therefore cause explosions when returned to the melting furnace.

Procedure C has solved the problems of procedures A and B, since with said procedure the continuous ingot casting is free of slag and oxides and it they achieve high levels of production in a single machine because the housing is long (at least as long as half of the wheel circumference) and therefore the surface large heat exchange and it is possible to change the length of ingot simply by varying the cutting step, and it is also possible vary the cross section of ingot by changing only the casting ring

However, even this procedure has inconvenience

With this procedure, in fact, the bar will solidifies on the wheel and you cannot remove the wheel (and for therefore straightens) if it has not completely solidified. This it requires a very long housing and therefore large dimensions for the cast iron wheel.

In addition, as a result of this fact, there are high equipment and installation costs. In fact, they may be required. wheel dimensions of more than 4 m in diameter. How the wheel is It must be placed on a vertical plane and supplied with metal liquid that arrives from the oven, the highest point, a very deep foundation well for the casting machine.

Another drawback is the fact that the bar that leaves the machine has to be reinforced. This requires a quite expensive straightening machine due to the cross section of the ingots and because the machine must comprise a set of punch and roller and a series of rollers of straightening that are synchronously motorized with the casting machine

The patent US-A-4 331 195 describes a machine continuous casting that has a combination of features as indicated in the preamble of claim 1 attached.

The purpose of the present invention of solve the problems and avoid the aforementioned problems previously, providing an apparatus for producing, by continuous casting, non-ferrous metal ingots that have all The advantages of the continuous casting process in a machine of the type of wheel and belt, but make it simpler in what It concerns the production and installation.

According to the invention, an apparatus is provided to produce, by continuous casting, non-metal ingots ferrous, as defined in independent claim 1 attached. The attached claims 2 to 17 define Other embodiments of the apparatus of claim 1. The invention it also provides the procedure, as defined in the claim 18 attached, to produce, by casting continuous in an apparatus as defined in claims 1 to 17, non-ferrous metal ingots.

Other features and advantages of the invention will become apparent from the attached detailed description of a preferred but not exclusive embodiment of the apparatus according to the invention, represented by way of non-limiting example only in the accompanying drawings, in which:

Figure 1 is a schematic side view of the apparatus according to the invention;

Figure 2 is a schematic side view of the continuous casting machine; Y

Figure 3 is a sectional view on a scale enlarged figure 2, taken along the line III-III.

With reference to the figures, the apparatus according to the invention, generally designated by numerical reference 1, comprises a casting machine 2 provided with a housing of scrollable cast iron

According to the invention, the housing is composed of a plurality of segments 3, which are arranged in succession and they can move along a path that has at least a straight portion 4 in the casting zone 5.

A portion of the cast iron housing, with a bottom 3a and side walls 3b and 3c, is formed in each segment 3 and is open on its sides directed towards the segments contiguous 3, as well as on its side which is arranged opposite regarding the background 3a.

Along portion 4, segments 3 they are substantially aligned and form a cast iron housing scrollable, continuous and rectilinear is closed, along a portion disposed after the casting zone, by means of closing 6 on its side which is arranged opposite to the bottom 3a of the different elements 3.

After portion 4, the trajectory of the segments 3 has a change of direction that produces an output gradual from the cast housing of the bar 7 produced by solidifying the metal in the cast iron housing.

In a convenient way, in segments 3, in portion 4, the side is arranged opposite the bottom 3a is directed up.

Portion 4, near the smelting zone 5, it is preferably tilted down in the direction in the which segments 3 move along the path correspondent.

In greater detail, segments 3 are connected to links 8 of a chain 9 that is closed in a loop and is wound around at least two gear wheels 10a and 10b that have horizontal and parallel axes to each other and are supported by the support structure of the machine Foundry 2, which is not shown for simplicity.

Segments 3 are preferably made of an alloy of copper and silver or an alloy of copper, chrome and zirconium, and the length of each segment 3 is exactly identical to the passage of the chain 9.

Portion 4 of the segment path 3 is formed by the upper portion of the chain 9 which is located between the round sitting its 10 which is located between the sprockets 10a and 10b. At least one of the sprockets 10a and 10b can be operated with a rotating movement around its own axis in a way known to itself to produce the advance of chain 9 and, therefore, of segments 3 to along the path formed by chain 9.

The links of chain 9 are articulated each other by pivots 11, whose axes are parallel to the axes of the sprockets 10a and 10b and mesh with the central area of the pivots 11.

In a convenient way, along the portion 4 of the trajectory of segments 3 there are means of support and guide for chain 9 that supports segments 3.

More particularly, two wheels spinning crazy 12a and 12b are mounted on pivots 11, close to their axial ends, laterally to the chain links and in opposite sides of each other, and two parallel profiles are provided each other 13a and 13b in portion 4, and wheels 12a and 12b are supported about it.

At least one of the wheels, the 12th wheel in the case represented, has a channel 14 that has a section V-shaped cross section and the corresponding profile 13a with which is coupled has a corresponding shape, to prevent the chain 9 move laterally at least along the portion Four.

Profiles 13a and 13b ensure alignment perfect of segments 3 along portion 4.

The means 6 for closing the side of the foundry housing that is arranged opposite the bottom 3a comprise a belt element 15, which is preferably made of steel and is slightly wider than the housing formed by the segments 3, and can move along a path that is facing, with one of its portions, portion 4. The coupling means act on the belt element 15 and press said belt element 15
against the edges of the upper side of the cast iron housing formed by the segments 3 along the portion 4.

The coupling means are constituted by rollers 16a and 16b, whose axes are parallel to the axes of the pivots 11. The rollers 16a and 16b are supported, so that can rotate around its own axis, using a support structure 17, which can be moved towards or away from portion 4 and is pushed to the same position 4 by springs or cylinders operated with fluids of a known type, not represented for reasons of simplicity, to press, by the rollers 16a and 16b, the belt element 15 against the segments 3 along portion 4.

Alternatively, the pressure action of the belt element 15 against the upper side of the segments 3 is you can get by sliding blocks instead of by rollers

The pressure action of the belt element 15 against the housing formed by segments 3 along the portion 4 made by rollers 16a and 16b or the blocks sliders to push wheels 12a and 12b against profiles 13a and 13b, thus ensuring the perfect alignment of segments 3 to length of portion 4 in all directions.

The belt element 15 is closed in a loop and roll up, to be tense in a convenient way, around two pulleys 18a and 18b that have horizontal axes that they are parallel to the axles of the sprockets 10a and 10b, and are supported by structure 17. Both pulleys are movable to tension the belt element 15 and allow its replacement. He mail element 15 moves normally by friction by contacting segments 3, or at least one of the pulleys 18a and 18b are operated with a rotating movement around its own axis to produce the advance of the element of belt 15 in accordance with the progress of segments 3 at along the common portion of the path.

Advantageously, there are means to cool the metal pouring into the foundry housing and the elements of the machine that are in contact with the poured metal. These means of cooling comprise a plurality of nozzles 20 for supply a cooling fluid (usually water), which they are integrated in a lower area and laterally to the segments 3 along portion 4, to affect your side bottom and to its side walls with the liquid of refrigeration.

The cooling means also comprise a plurality of nozzles 21 for supplying a fluid of refrigeration, they are faced in a superior region of the portion of the belt element 15 that at each moment is coupled with the segments 3 along portion 4, to strike, with the fluid of cooling, the upper face of the belt element 15 which is couples with segments 3.

The casting shell portion formed in each of the segments 3 preferably has, in a section transversal with respect to the direction of advance of segments 3 to along the path determined by chain 9, the form of an isosceles trapezoid that is open on its parallel side more long.

Conveniently, the apparatus according to the invention comprises, after the casting machine 2 along the forward direction of the bar leaving the casting machine 2, a first cooling station 31, preferably of tunnel type

After the first cooling station 31 there is a cutting unit 32, preferably of the rotating type, to cut into bars of a predetermined length the bar of produced metal, and after cutting unit 32 there are conveniently a second refrigeration station 33 of type tunnel or tank

At the exit of the second station of cooling 33 there is a station 34 for stacking, weighing and bonding  automatic with ingot straps.

The device can be completed with a system for continuous marking of the ingots to mark on them All desired identification data.

The operation of the apparatus according to the invention It is as follows.

The molten metal is supplied in a way continues inside the crucible 25, in which the level of said metal is controlled and held constant, means of a kind known, for example of the type currently used in machines continuous casting of wheel and belt type.

From the cauldron, the metal is poured and supplies the movable housing, which is formed by segments 3 along portion 4, through the channel of foundry 26 in a manner similar to what is currently produced in continuous casting machines of the wheel type and belt.

In the movable housing, the metal cools gradually through the cooling fluid jets emitted by nozzles 20 in 21 and solidifies, generating the bar 7, which leaves the housing in the area of the toothed 10b

It should be noted that the bar that leaves the housing is straight and that to make it leave the housing is not require any expulsion element that could cause plastic deformation of the bar, as happens on the contrary in continuous casting machines of the wheel type and belt.

Thanks to this fact, it is possible to limit the portion length 4 and therefore have a machine foundry that has reduced dimensions, since the presence of a central part that has not yet solidified in the Bar interior 7 is acceptable.

The passage through the first station of cooling 31 completes the solidification of the bar 7 and its temperature is taken to the most appropriate level for later cutting operation, that is, at the optimum temperature to reduce to a minimum shear stresses in the compatible extension with solidification and uniformity of the bar 7.

In this station 31, the cooling of the bar 7 can be of spray type, which when having an action direct has a high efficiency and therefore requires periods of shorter time.

After cutting, bar elements 7 or ingots cool more in the second refrigeration station 33 at a temperature that is close to room temperature, and at then they are stacked, weighed and joined with straps on the station 34. The belts, in fact, would loosen due to the thermal contraction of the ingots if joined at a temperature high.

The ingots obtained with the apparatus according to the invention have a rectilinear structure that is not subject to plastic deformation after solidification, which occurs in a continuous housing formed by a sequence of segments concatenated and closed by means of a continuous belt element. The metallographic discontinuities can be detected in said ingots in the sections that correspond to the surfaces of contact of the different segments that make up the housing.

In practice, it was found that the apparatus according to the invention fully satisfies the purpose and the desired objectives, since its performance is similar to that of apparatus with a continuous casting machine of the wheel type and belt, but with significantly smaller dimensions and about also lower costs.

In particular, the foundations of the machine Casting of the apparatus according to the invention are considerably less deep and, therefore, many cheaper than foundations required by continuous casting machines of type of wheel and belt.

The apparatus according to the invention also allows produce a straight continuous bar that does not require the use of complicated ingot straightening machines with a side punch roller and motorized straightening rollers synchronized with the speed of the line.

Another advantage of the apparatus according to the invention is that it is possible to vary the cross section of the ingots produced and the level of agricultural production required simply replacing the segments that form the cast iron housing, and optionally extending the segment chains.

The device thus conceived is susceptible to numerous modifications or variations, which are included in the field of the inventive concept; all the details are also can replace with other elements technically equivalent.

In practice, the materials used as well As the dimensions, they can be any according to the requirements and state of the art.

Where the technical characteristics cited in any claims are followed by reference signs, those reference signs have been included for the sole purpose of increase the intelligibility of the claims, and in Consequently, these reference signs have no effect limiting on the interpretation of each element identified to example by these reference signs.

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References cited in the description

This list of references cited by the Applicant is only for the convenience of the reader. Not a part of the European Patent document. Although it has had a great careful to collect the references, the presence cannot be excluded of errors or omissions and therefore the EPO declines any Responsibility in this regard.

Patent documents cited in the description

US 08245404 B [0008]

US 4331195 A [0023]

Claims (18)

1. Apparatus (1) for producing, by continuous casting, non-ferrous metal ingots, comprising a continuous casting machine (2) provided with a movable cast iron housing, said housing being composed of a plurality of segments (3) arranged in succession, each segment having a portion, with a bottom (3a) and side walls (3b, 3c), of said cast iron housing formed in this manner and which opens on sides directed towards the adjacent segments (3); said segments (3) being displaceable along a closed path having at least a substantially straight portion (4) in the casting zone (5); said segments (3) being, along said at least a portion (4) of said path, substantially aligned and forming a cast iron housing, with a bottom and side walls, which is continuous, substantially straight and closed , along at least a portion (4) of said path after the smelting zone (5), by means of closing means (6) on its side it is arranged opposite to the bottom (3a); said segment path having after said substantially straight portion (4) a change in the direction for a gradual exit of said casting housing from a metal rod (7) produced by solidifying the metal in the casting housing, being connected said segments (3) to links (8) of a chain (9) that is closed in a loop, the links (8) of said chain (9) being articulated with each other by pivots (11); the apparatus (1) being characterized by the fact that two wheels (12a, 12b) are mounted on each of said pivots (11), close to their axial ends, and rest, along said substantially straight portion ( 4) of the trajectory of the segments (3), on support and guide profiles (13a, 13b). 2. Apparatus (1) according to claim 1, characterized in that along said substantially straight portion (4), the side of said cast iron housing that is arranged opposite the bottom (3a) is directed upwards. 3. Apparatus (1) according to claim 1, characterized in that said substantially straight portion (4) of the trajectory of the segments (3), close to said smelting zone (5), is inclined downwards in a direction in which the segments (3) advance along said path. 4. Apparatus (1) according to claim 3, characterized in that said loop is wound around at least two sprockets (10a, 10b), which have horizontal axes parallel to each other; said substantially straight portion (4) of the segment path (3) being formed by the upper portion of said chain (9); at least one of said gears (10a, 10b) being able to be driven with a rotating movement around its own axis to produce the advance of said segments (3) along said path. 5. Apparatus (1) according to claim 1, characterized in that said closing means (6) comprise a belt element (15) that can be moved along a path that is facing, with one of its portions, with said substantially straight portion (4) of the trajectory of said segments (3); coupling means (16a, 16b) being provided that are suitable for pressing said belt element (15) against said segments (3) in said portion substantially straight than the path of the segments (3). 6. Apparatus (1) according to claim 5, characterized in that said belt element (15) is closed in a loop and is wound around at least two pulleys (18a, 18b) with horizontal axes that are parallel to the axles of said gear wheels (10a, 10b). 7. Apparatus (1) according to claim 6, characterized in that at least one of said two pulleys (18a, 18b) can be operated with a rotating movement around its own axis to produce the advance of said belt ( 15) to match the advance of said segments (3) along the common portion (4) of the path. Apparatus (1) according to claim 5, characterized in that it comprises means (20) for cooling the metal poured into said segments (3) along said substantially straight portion of the segment path (3) . 9. Apparatus (1) according to claim 8, characterized in that said cooling means comprise a plurality of nozzles (20) for supplying the cooling fluid, which is suitable for striking said segments (3) with said fluid. 10. Apparatus (1) according to claim 8, characterized in that said cooling means comprise a plurality of nozzles (21) for supplying a cooling fluid, which is suitable for striking, with said fluid, a portion of said belt element (15) that is pressed against said segments (3). 11. Apparatus (1) according to claim 4, characterized in that means are provided for supporting and guiding the chain supporting said segments (3) in said substantially straight portion (4) of the segment path (3) . 12. Apparatus (1) according to claim 4, characterized in that said pivots have axles that are parallel to the axles of said gear wheels (10a, 10b). 13. Apparatus (1) according to claim 6, characterized in that said pulleys (18a, 18b) supporting said belt element (15) is mounted on a structure that does promote towards and away from said substantially straight portion ( 4) of the trajectory of the segments (3). 14. Apparatus (1) according to claim 1, characterized in that the portion of the foundry housing formed in each of said segments (3) has, in a cross section relative to the direction of advance of said segments ( 3) along the corresponding path, a trapezoidal shape that is open on the longest parallel side. 15. Apparatus (1) according to claim 1, characterized in that it comprises, after said continuous casting machine (2) along the direction of advance of said segments (3) along said portion substantially straight (4) of its trajectory, a first station (31) to cool the metal bar (7) leaving said continuous casting machine (2). 16. Apparatus (1) according to claim 15, characterized in that it comprises, after said first cooling station (31) along the direction of advance of the metal bar (7), a station (32 ) to cut said bar (7) into segments (3). 17. Apparatus (1) according to claim 16, characterized in that it comprises, after said cutting station (32) along the direction of advance of the metal bar (7), a second station (33 ) for cooling the metal bar (7). 18. Process for the production, by continuous casting in an apparatus (1) as defined in claims 1 to 17, non-ferrous metal ingots, characterized in that it comprises the steps of: - continuously diffuse molten metal inside a continuous cast iron housing and substantially rectilinear that is composed of a sequence of concatenated segments (3) of an ingot mold; - cooling said cast iron housing for at least partial solidification of the foundry metal; - continuously remove the bar (7) produced by solidifying the metal of said housing of casting without producing plastic deformations in said bar; - cut said bar (7) into segments.