EP2131976B1

EP2131976B1 - Bearing structure for continuous casting machine

Info

Publication number: EP2131976B1
Application number: EP08717112A
Authority: EP
Inventors: Daniele Andreatta; Alfredo Poloni
Original assignee: Danieli and C Officine Meccaniche SpA
Current assignee: Danieli and C Officine Meccaniche SpA
Priority date: 2007-03-02
Filing date: 2008-02-26
Publication date: 2010-12-08
Anticipated expiration: 2028-02-26
Also published as: DE602008003907D1; CN101622089A; ATE490829T1; US20100038049A1; ITUD20070047A1; EP2131976A1; CN101622089B; WO2008107339A1

Abstract

A bearing structure for a curved continuous casting machine includes a monolithic and integrated structure, made of metal sheet, substantially closed and self-bearing, having at the upper part a seating or base suitable for the assembly of an ingot mold and accommodating along the casting curve both the rolls for containing and guiding the cast product, and also at least part of a secondary cooling system.

Description

FIELD OF THE INVENTION

The present invention concerns a bearing structure for a continuous casting machine.
More particularly, the invention concerns a monolithic and integrated bearing structure, particularly suitable to be used for the installation of a compact curved continuous casting machine, in particular for the continuous casting of billets and blooms, for example but not only, for commercial steels, but also for quality steels.
The monolithic and integrated bearing structure according to the present invention allows to install a single line and/or multi-line continuous casting machine, considerably reducing and simplifying the assembly operations in loco, drastically reducing times required for start-up, and also the costs of initial investment.
Furthermore, the bearing structure according to the invention ensures an easier access for operators to the casting line, for example for maintenance operations, and guarantees greater operating safety for said operators.

BACKGROUND OF THE INVENTION

The general structure of a continuous casting machine for billets or blooms is known, comprising in its essential elements an ingot mold with a square or rectangular section, the foot rolls and a curved removal and guide line, associated with a secondary cooling system.
Downstream of the removal and guide line there is normally a straightening device, the function of which is to dispose the cast billet or bloom flat, in order to accompany it towards the equipment located downstream, for example shearing means, removal and parking means for the dummy bar, the accumulation and heating systems and/or the rolling train.
Examples of said curved continuous casting machines are shown for example in JP 59110453 and CH 597944 .
It is known that the installation of a curved continuous casting machine normally requires expensive civil engineering works, such as excavations, foundations for machines, concrete casts, bearing columns, reinforced concrete beams and more, all of which makes the installation times extremely long, and initial investment costs extremely high.
Moreover, known solutions require a long time, and a specialized work force, to make the connections to the user machines on site, for example to connect the pipes to feed water, air, piping, electric connections and other.
Furthermore, to make said connections requires a precise and expensive initial planning step, so that all the connection systems and the auxiliary and accessory equipment are positioned in places which on the one hand do not interfere with the daily operations of the casting machine and are adequately protected, and on the other hand are easily and quickly accessible and maintainable in the event of problems and break-downs.
Another problem in known solutions is the huge need for space in the shed for the installation of the usual continuous casting machines, which moreover are normally located on different planes. Another problem is the expense of the transport in loco of the components of the continuous casting machine.
Still another problem is the difficult access for operators to the individual segments of the line, for example to make inspections, maintenance, replacement of components, or to solve problems of blockages or other type.
Purpose of the present invention is to achieve plants for rolling billets or blooms of the compact type, with pre-assembled components, also of the structural type, already complete with pre-tested plant engineering, with shorter assembly time, also suitable to be installed in limited spaces.
In the light of the above, purpose of the present invention is therefore to solve these problems, proposing a solution able to drastically reduce the works of civil engineering needed for the installation of a continuous casting machine in a plant, the design and need for labor to perform the connections to the user machines, the volumes of transport and loading/unloading the components, and all the other works required to install the continuous casting machine.
The Applicant has devised, tested and embodied the present invention to obtain this purpose, and other benefits and advantages as shown hereafter, including for example greater safety for the workers.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claim, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.
In accordance with the present invention, the purpose set forth above is obtained by using a monolithic and integrated structure, made of metal sheet, substantially closed and self-supporting, which has a seating suitable for the assembly of an ingot mold and which accommodates both the containing and guiding rolls disposed along the curvilinear path of the cast product, and also the secondary cooling system.
The bearing structure is advantageously made from workings on machine tools which allow to obtain limited tolerances in the construction of the components.
With the bearing structure according to the invention, during the assembly step of the casting line, it is possible to obtain immediately a perfect alignment of the containing and guiding rolls of the cast product, so that it is no longer necessary to perform all the operations that normally, in conventional assembly operations, are actuated to effect said alignment subsequent to installation.
Moreover, the monolithic bearing structure according to the invention does not require expensive works of civil engineering, such as the traditional foundations for the machines, but simply a plane supporting surface on which it can be anchored.
In an advantageous embodiment of the invention, the whole bearing structure is anchored to the ground by means of at least a metal plate, which functions as a base, incorporated into the floor and made solid therewith, for example, but not necessarily, by means of threaded bars or tie rods. This allows to reduce the installation times and initial investment costs.
In a preferential embodiment of the invention, at least the upper portion of the casting curve is easily accessible by means of a series of opening covers that allow selective opening to adjacent individual segments of the casting line.
The covers have a box-like structure, substantially U-shaped, conformed so as to be disposed, in the closed position, as close as possible to the casting line, almost so as to surround it; in the zones where it is connected to the containing structure of the cast product, leakages of water are prevented by using, for example, suitable labyrinth seals.
In this way, we obtain a great overall saving of space around the continuous casting machine, so that the size of the compartment containing the billet/bloom along the casting curve is reduced to a minimum. Moreover, even in the open position the covers do not need big spaces around the casting machine in order to be moved.
In a preferential embodiment of the invention, the covers can be opened in an upward direction, so as to allow operators access to the line from both sides of the line.
According to a variant, the covers can be opened in a lateral direction. In this case, the opening/closing of the covers is performed in sequence, to prevent the ends of two adjacent covers from overlapping.
The presence of opening covers allows to considerably facilitate, for the staff, all the interventions of checking and ordinary (daily) maintenance, checking the insertion of the dummy bar when casting is started, the management of possible problems, such as leakage of liquid steel due to the breakage of the skin, and other: all this promotes greater rapidity in operations and greater safety for the workers.
In one embodiment of the invention, inside the covers at least the upper containing and guiding rolls for the billet/bloom are assembled.
According to a variant, inside the box-like containing structure of the cast product support means, alignment means and/or command means of the lower rolls are assembled.
According to another variant, the spray nozzles of the secondary cooling system are assembled inside the covers.
Thanks to this pre-assembly of functional elements of the casting line, when the covers are closed, all the relative equipment assembled inside is already in the position of use, therefore without requiring further steps of adjustment or tuning, both in terms of geometry and alignment, all of which guarantees greater efficiency of the process.
The covers are advantageously cooled by suitable means, for example sprays, or by means of a water jacket structure with an independent circuit, and they are driven to open/close for example by means of hydraulic actuators or jacks.
As mentioned above, the monolithic casting structure advantageously provides on the outside all the necessary drive and command elements, such as for example the rapid attachments for water and electricity, the system for lubricating the bearings, the piping, etc. These elements are easily and quickly interfaced with the appropriate service lines of the plant (electricity, water plant, oil plant, air plant, etc.).
In a preferential embodiment, in the upper part of the casting line, it is provided to suck in the water vapors generated by the process, with a suitable aspirator; the suction is facilitated thanks to the limited size of the casting chamber, and the fact that the closed monolithic structure produces a "chimney effect".
The plant according to the present invention allows to considerably simplify the works of civil engineering for installation, since it does not require complex foundations and does not require the traditional bearing structure made of reinforced concrete and network of girders to support the various planes of the structure.
The bearing structure according to the invention has limited weight and size and, since it is made largely of modular elements, it is easy to transport.
The presence inside and/or outside the monolithic structure of all the drive and command devices allows rapid installation and rapid start-up of the plant.
Thanks to all these details indicated above, the continuous casting machine thus made allows to use adjacent casting lines in parallel, if it is desired to increase productivity.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

fig. 1 is a perspective view of a bearing structure for a continuous casting machine according to the present invention;
figs. 2 and 3 show respectively a lateral view and a view from the rear of the bearing structure in fig. 1;
fig. 4 is a perspective view of the bearing structure in fig. 1 in which the covers with lateral opening can be seen;
fig. 4a shows an enlarged detail of fig. 4;
figs. 5 and 6 show, respectively with a perspective view and a lateral view, the bearing structure in fig. 4 in which the covers open upwards;
fig. 7 shows a continuous casting machine that uses a bearing structure according to the present invention inserted upstream of a partly shown segment of line; and
fig. 8 is a perspective view of another form of embodiment of the bearing structure according to the invention.

DETAILED DESCRIPTION OF SOME PREFERENTIAL FORMS OF EMBODIMENT

With reference to the attached drawings, and particularly fig. 7, a bearing structure 10 for a curved continuous casting machine according to the present invention is disposed upstream of a straightening unit 11, a device 12 to insert, remove and park a dummy bar 13, and shears 14.
Downstream of the shears 14, and not shown here, there may be a heating furnace present and a rolling train directly connected with the product arriving from the casting machine in the case of an application to a production plant of the endless type.
The bearing structure 10 according to the invention in this case is disposed in cooperation with a bridge 15, defining the casting plane 17, having a width advantageously equal to that of a bay of the shed of the plant where the casting machine is installed.
With this configuration it is possible to create a passage space at the side of the casting line, which allows the workers and the equipment to have access upstream and downstream of the plant, thus allowing a greater integration of the areas.
Under the casting plane 17 an intermediate plane 16 is provided, where all the auxiliary services are accommodated, such as for example the oil-dynamic units, the electric panels, the regulation valves, the piping, the collectors.
The casting plane 17 is advantageously not bulky and can have a very rational disposition of the auxiliary devices.
The bearing structure 10 in this case is anchored to the ground by means of a metal plate 21, functioning as a base, incorporated into the floor. A column element 20 is attached on the metal plate 21, defining a structure which in this case is quadrangular, consisting in this case of four metal beams 22, for example H beams or other type (figs. 1 and 2).
At the top end of the column element 20, inside a containing frame 18, a flange 23 is assembled which defines a seating or base, in which an ingot mold 24 is housed and assembled.
The flange is advantageously of the inter-changeable type so as to allow the assembly of an ingot mold 24 different in the event of a change in format of the billet/bloom 26.
From the column element 20 a series of lateral and bottom panels 25, made of metal sheet, attached one to the other in sequence, branch off towards the bottom and towards the base; they define a box-like structure which houses and defines the curved removal and guide line of the billet/bloom 26.
The lateral and bottom panels 25 define a seating for the housing and assembly at least of the lower rolls and the nozzles of the secondary cooling system.
On the lateral panels 25 a series of opening covers 28 are hinged, by means of respective assembly plates 27, substantially U-shaped, which open laterally in the case shown in fig. 4, whereas in the case shown in fig. 6 they open upwards with respect to the casting line.
The covers 28 may be driven to open by means of respective hydraulic or pneumatic jacks 36, which allows selective access to respective segments of the line for a worker 29, also thanks to the presence of a system of stairs 30 that develops adjacent to the panels 25, in order to carry out inspection or maintenance operations, and in the event of incidents such as blockages or break-outs.
The U-shaped surrounding box-like structure of the covers 28 allows to reduce to a minimum indispensable the size of the casting chamber downstream of the ingot mold 24, thus giving a better thermodynamic control of the conditions of progressive solidification of the billet-bloom 26, and an easier control to prevent leakages of the cooling water.
When the covers 28 open from above as in the case shown in fig. 4, where the covers 28 can be seen progressively closing from the bottom of the casting line, the opening and closing of the covers 28 is performed sequentially so that there is no overlapping of the adjacent ends.
According to the variant shown in fig. 8, the first segment of the casting line downstream of the ingot mold 24 comprises a substantially closed chamber 37, which may or may not comprise the column element 20, and which allows easy access to the operators. The closed chamber 37 allows to control the cooling system better and more easily during casting and is less subject to reverberation by the billet/bloom 26 since the walls are more distant therefrom compared with the solution with covers 28. The subsequent part of the casting curve, on the contrary, provides the opening covers 28, as in the solutions previously described.
Inside the covers 28, as shown in detail in fig. 4a, both the upper rolls 32 to contain and guide the billet/bloom 26 are advantageously assembled, and also the nozzles 42 of the secondary cooling system. Thanks to this system of pre-assembly, at the moment the covers 28 are installed, and when they close, the curved removal and guide line of the billet/bloom 26 is already completely configured, without needing alignments and further adjustments.
In a first embodiment of the invention, only one of the roll units, the upper or the lower, is motorized, while the other is idle.
According to a variant, both the roll units are motorized. According to another variant, both the roll units are idle.
In the preferential embodiment shown in figs. 2 and 8, the base plate 33 of the column element 20 has rapid attachment means 34, accessible from outside, for connection to the service sources, for example water, air, electricity, possible oil plant, piping and other.
The rapid attachment means 34 can be used to activate the necessary connections in an extremely rapid and simple manner, without requiring specialized labor and without needing complex positioning which can oblige the workers to perform complex and dangerous operations. The rapid attachment means 34 is connected, inside the column element 20, with pipes and cables, indicated in their entirety by the reference number 35, which serve to deliver water, electricity and other to the delivery points distributed inside the bearing structure 10.
The water used for the secondary cooling is conveyed and channeled, together with the scale, along a slide advantageously made with the bottom panels 25 of the casting curve, and subsequently discharged from the lower end of the curve into the so-called "flushing", that is, the water treatment plant of the works.
According to a variant, the casting curve is made without the bottom panels and the lateral panels extend to the ground so as to constitute two continuous lateral walls. In this case, the cooling water is not conveyed along the curve, but falls directly to floor level, where it is collected in the flushing.
Modifications and variants may be made to the present invention, all of which shall come within the field of protection defined by the attached claims.

Claims

Bearing structure for a curved continuous casting machine, characterized in that it comprises a monolithic and integrated structure, made of metal sheet, substantially closed and self-bearing, having at the upper part a seating or base (23) suitable for the assembly of an ingot mold (24) and accommodating along the casting curve both the rolls for containing and guiding the cast product (26), and also at least part of the secondary cooling system (42).
Bearing structure as in claim 1, characterized in that it has a metal plate (21) functioning as a base and able to be incorporated into the floor.
Bearing structure as in claim 1 or 2, characterized in that it has a plurality of lateral and bottom panels (25) defining a body supporting at least the lower rolls (32) containing and guiding the casting line.
Bearing structure as in claim 1 or 2, characterized in that, at least in correspondence with the lower portion of the casting curve, it has a plurality of opening covers (28) able to allow access to the relative segments of the casting curve.
Bearing structure as in claim 4, characterized in that said opening covers (28) have a substantially U-shaped structure surrounding the relative segment of the casting curve.
Bearing structure as in claim 4, characterized in that said covers (28) open in an upward direction with respect to the casting line.
Bearing structure as in claim 4, characterized in that said covers (28) open in a lateral direction with respect to the casting line.
Bearing structure as in claim 4, characterized in that inside said covers (28) at least the upper rolls (32) for containing and guiding the casting line are assembled.
Bearing structure as in claim 4, characterized in that inside said covers (28) at least part of the nozzles (42) of the secondary cooling system of the casting line are assembled.
Bearing structure as in any claim hereinbefore, characterized in that it provides rapid attachment means (34, 35) for connection to a source of electric and/or water feed.
Bearing structure as in any claim hereinbefore, characterized in that it provides inside it rapid connection means (34, 35) and interconnection means to feed the lubrication systems.
Bearing structure as in any claim hereinbefore, characterized in that it comprises a substantially closed chamber (37) disposed immediately downstream from the exit of the ingot-mold (24) and covering at least the upper segment of the casting curve.
Bearing structure as in any claim hereinbefore, able to be installed in a shed of a production plant, characterized in that it is located in cooperation with a bridge (15), defining the casting plane (17), having a width substantially equal to that of a bay of said shed.
Bearing structure as in claim 13, characterized in that below the casting plane (17) the bridge (15) comprises at least an intermediate plane for accommodating at least part of the services auxiliary to casting.