CN110506449B

CN110506449B - Heating device for metal products

Info

Publication number: CN110506449B
Application number: CN201880026259.XA
Authority: CN
Inventors: 法比奥·瓜斯蒂尼; 安德烈·科杜蒂
Original assignee: Rotelec SA
Current assignee: Rotelec SA
Priority date: 2017-02-22
Filing date: 2018-02-22
Publication date: 2022-04-05
Anticipated expiration: 2038-02-22
Also published as: IT201700020203A1; WO2018153976A1; EP3586567A1; EP3586567B1; KR20190120280A; CN110506449A; KR102219105B1

Abstract

Heating device (10) for heating one or more edges (12) of a metal product (11) selectively and with a desired thermal power by electromagnetic induction, said heating device comprising a magnetic core (13) having a through hole (14) and at least four polar extensions (18).

Description

Heating device for metal products

Technical Field

The present invention relates to a heating device for metal products used in the steel-making field, for example in casting plants, rolling plants, combinations thereof or other plants, where the metal product needs to be heated in each case and at different points. The heating device heats the metal product using electromagnetic induction.

By way of non-limiting example, the metal product under consideration comprises a billet (billet), bloom, wide plate, or a metal product or semi-finished product having a square, rectangular or polygonal cross section with edges.

Background

In the production of metal products (for example, billets, blooms or other similar products), it is known to heat or maintain the products at a predetermined temperature, so as to obtain each time a metal product free from cracks and having the desired characteristics.

This can be achieved by using a suitable induction heating device which, depending on the magnetic field generated by it in each case, in particular by the current induced in the metal product, makes it possible to heat a portion of the cross section of the metal product by the joule effect.

However, the known induction heating devices do not allow to obtain a uniform thermal power distribution throughout the entire volume of the metal product, nor to control the power distribution point-by-point or selectively.

In fact, after the known heat treatments, the metal product clearly lacks the thermal uniformity corresponding to the edges, which can therefore be cooler than other areas of the metal product.

These differences in temperature can lead to surface cracks or other unwanted flaws in the metal product.

Furthermore, in particular in metal products obtained by continuous casting, in which the edges of the metal product are positioned differently, for example the intrados (intrado) edge and the extrados (extrado) edge, the resulting metal product generally lacks thermal uniformity, which also varies with respect to the specific edge.

In such a context, it is obviously necessary to have at least all edges under the same heating conditions, but it is also obviously necessary to have them heated at all points and differently due to the specific process requirements.

The heating may be carried out in the casting step itself or downstream.

Induction heating devices are also known which are configured to heat two opposite edges at a time, or which have two or more ferromagnetic cores, each of which is provided with two polar extensions.

Among these, the solution shown in the document US 5.412.183 provides for heating the metal product simultaneously on staggered planes.

Furthermore, these known solutions do not allow to selectively vary the heating of the various edges, nor to vary the thermal power delivered to the various edges, possibly in each case according to the needs.

There is therefore a need to improve the prior art and to provide a heating device that overcomes at least one of the disadvantages of the prior art.

It is an object of the present invention to provide an induction heating device which is capable of heating one or more edges of a metal product at different points and in each case, so as to heat the metal product selectively and in a desired manner, so as to ensure uniform results.

Another object of the present invention is to provide an induction heating device which is capable of making the heat distribution of all edges uniform and also of making the thermal powers transferred to them different.

Another object is to provide a heating device which is capable of heat-treating one or more edges simultaneously with respect to the heat treatment required in each case.

Another object is to provide an induction heating device capable of heating specific or defined areas of metal products having various cross-sections, also as required or desired, while maintaining good performance in the transfer of thermal power.

The applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

Disclosure of Invention

The invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

In accordance with the above object, the present invention relates to an induction heating apparatus comprising a magnetic core having a through hole and at least four polar extensions disposed at equal angles along the periphery of the through hole.

According to one aspect of the invention, the polar extensions are located on the same lying plane and are connected to each other physically and/or functionally in succession by means of a connection portion, each polar extension being provided with a respective electrical coil having electrical energy independent of the coils of the other polar extensions, and the polar extensions being able to define in each case the polarity, frequency and power delivered by the respective polar extension.

Such a configuration allows using an induction heating device to heat selectively and with a desired and suitably different electric power one or more edges of a metal product having four or more edges, such as a steel billet, a steel ingot, a wide plate, or a metal product or semi-finished product having a square or rectangular cross section, or possibly a metal or mechanical artifact.

According to a possible embodiment, the polar extension is selectively movable with respect to the through hole; advantageously, but not in a limiting way, the movement of the polar extensions is orthogonal or substantially orthogonal to the transport axis in which the metal product is transported.

The movement of the polar extensions allows to adapt and optimize the distance of the respective polar extension with respect to the surface of the metal product, so as to adapt the transport space of the through hole with respect to the specific cross section of the metal product to be treated.

In this way, it is possible to obtain a greater heating efficiency and safety level even if the walls of the metal product are not straight on the one hand and/or are not orthogonal with respect to each other on the other hand.

According to a possible embodiment, the magnetic core comprises one or more magnetic sections, between which cooling plates are interposed, each of said magnetic sections comprising a desired plurality of magnetic sheets.

According to a possible variant, the electrical coils are cooled by cooling tubes in which a cooling liquid is carried.

Drawings

These and other features of the invention will become apparent from the following description of certain embodiments, which are given by way of non-limiting example with reference to the accompanying drawings.

FIG. 1 is a perspective view of a heating device according to the present invention;

FIG. 2 is a cross-sectional view of a heating device according to the present invention;

3-6 are four cross-sectional views schematically illustrating four use configurations of the heating device according to the invention;

7-9 are three cross-sectional views schematically illustrating three aspects of possible embodiments of the heating device;

FIG. 10 is a cross-sectional view of a modified embodiment of the heating device;

figure 11 is a cross-sectional view of a variant embodiment of the heating device in the configuration of use;

fig. 12 and 13 are two cross-sectional views of two variant embodiments of the heating device.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It will be appreciated that elements and features of one embodiment may be advantageously incorporated in other embodiments without further recitation.

Detailed Description

The embodiments described herein with reference to the drawings relate to a heating device 10 for a metal product 11.

By metal product 11 we mean a metal product or semi-finished product, such as a billet or bloom, or a molten metal product or semi-finished product having a square, rectangular or polygonal cross-section, with one or more edges 12.

According to the invention, the heating device 10 comprises a magnetic core 13 with a through hole 14 through which the metal product 11 is conveyed.

The magnetic core 13 may comprise a plurality of magnetic sheets 15, which are superimposed and clamped to each other in a known manner to form a single body or a whole made up of a plurality of magnetic sectors 16.

The magnetic sheet 15 may be made of a ferromagnetic material, such as iron, nickel, cobalt, alloys thereof, or other suitable materials.

The magnetic core 13 may be implemented in whole, or in part, in one or more non-sheet form magneto-dielectric (magneto-dielectric) dense materials.

For example, the magneto-dielectric dense material may include ferromagnetic metal powder contained in an insulating matrix.

According to a possible embodiment, the magnetic core 13 comprises one or more magnetic sections 16 between which cooling plates 17 are provided, each of said magnetic sections 16 comprising a desired plurality of magnetic sheets 15.

The cooling plate 17 may be of an active cooling type or a passive cooling type, and may also be configured to shield (screen) the heating device 10.

The magnetic core 13 has at least four polar extensions 18 arranged at equal angles along the periphery of the through hole 14.

In one embodiment, the polar extensions 18 extend the entire length of the magnetic core 13 so that when the heating device 10 is in operation, it can heat the entire longitudinal portion of the metal product 11 conveyed in the through hole 14.

According to a possible embodiment, if the through hole 14 is substantially square, also with possible rounded edges, the polar extensions 18 are arranged at the sides of the square delimited by the perimeter of the through hole 14 and facing the inside of the through hole 14.

For each polarity extension 18, it is possible to define an upper end and a lower end. Polarity extension 18 is configured to act between the upper and lower ends.

The extending action of the polar extensions 18 enables heating of one or more edges 12 along the longitudinal extension of the metal product 11.

According to the invention, the polar extensions 18 lie in the same plane of lie. The plane of lie is defined as the plane in which all upper ends or all lower ends of polarity extension 18 lie.

According to an aspect of the invention, the polar extensions 18 are connected to each other by a connection portion 19, which is part of the magnetic core 13.

By the term "connected", we mean that polarity extension 18 and connection portion 19 are continuously connected to each other and that polarity extension 18 and connection portion 19 are functionally continuously connected, i.e. the lines of magnetic flow 22 can circulate between them even if there is a minimum air gap.

According to a possible embodiment, the connection portion 19 and the polar extension 18 are two or more bodies and are structurally or functionally connected to each other to obtain a continuous magnetic flow.

Each polar extension 18 is provided with a respective electrical coil 20, which is connected to a separate electrical power source 21, which is able to define the polarity (see the direction of the lines of magnetic flow 22) and possibly the specific supply power of the respective polar extension 18 in each case.

According to possible embodiments, polar extensions 18 and connection portions 19 may constitute the magnetic core 13 in a single body, or in several bodies structurally or functionally connected to each other to obtain a continuous magnetic flow.

Such a configuration, in which the continuity of the magnetic connection between the polar extension 18 and the connection portion 19 is substantially uninterrupted, allows the line of the magnetic flow 22 to be closed by the connection portion 19, thereby minimizing energy loss.

This allows the magnetic flow 22 generated by one polarity extension 18 to be closed in one or both polarity extensions 18 adjacent thereto.

According to a possible embodiment, each of the electrical coils 20 comprises an electrical cable 23 connected to the electrical power source 21, said cable 23 being wound around one of the polar extensions 18 to form a reel having one or more spirals.

The electrical coils 23, which are associated with the ranges of frequency and power, may all be identical or different, according to the specific and point-by-point requirements of each metal product 11 to be treated concerned.

Depending on the deformation, the electrical coil 20 may be replaceable or may be made replaceable.

In the drawings, the coil is characterized according to the direction of the current: "x" represents the input current and ". multidot..

According to a possible embodiment, the cable 23 may be realized in a tubular form from an electrically conductive material (for example a material having a high electrical conductivity like copper) and the cable 23 is cooled with a cooling liquid passing through it.

According to a possible embodiment, in order to slow down the deterioration of the cables 23, these cables can be positioned inside respective cooling tubes 24, in which a cooling liquid passes.

The cooling tube 24 may have a shape that is connected to the free space around the polar extension 18 and may be supplied with a cooling fluid, such as treated or untreated water, or oil or other fluid conducting temperature, through a power outlet 24a connected to one or more power sources.

Referring to fig. 3-6, four possible use configurations are shown, in which a magnetic field and corresponding lines of magnetic flow 22 are generated, selectively activating one or more electrical coils 20. The activation may also relate to the power delivered.

Depending on the direction of the current, its intensity, its frequency and the electrical coil 20 through which it passes, a respective current is induced in the metal product 11, and in particular the current corresponding to its edge 12.

Due to the joule effect, and in the vicinity of the edge 12, the induced current heats the respective zone 25 in each case and point by point. More specifically, reference numeral 25 in the drawings indicates the area of the heated edge, where the variable size of the dashed circle shows a larger or smaller affected area, due to the greater or lesser power delivered by the corresponding polar extension 18 affecting the particular area.

The shape and size of the polar extension 18 are configured to generate a magnetic field transverse to the direction of advancement of the metal product 11 relative to the morphology of the metal product 11.

In one form, the polar extensions 18 may have surfaces from which the lines of magnetic flow 22 exit/enter in pairs substantially parallel and which face the through hole 14 of the magnetic core 13.

According to a variant, one or more polar extensions 18 are shaped according to the physical shape of the metal product 11 to be treated.

According to possible non-limiting example embodiments, the surface of one or more polar extensions 18 may be wedge-shaped, with inclined edges, with a convex or concave shape, parabolic or hyperbolic.

These configurations effectively allow the magnetic flow to be directed to the metal product 11 by increasing the efficiency of the power transfer from the polar extensions 18 to the metal product 11.

According to a possible embodiment, one or more polar extensions 18 may comprise an exchangeable portion provided with a shaped surface according to the metal product 11 to be treated, said shaped surface facing, in use, the through hole 14.

According to a possible variant, at least one of the polar expansions is conformed in a personalized manner according to the contour of the metal product 11. In other words, according to a possible variant, one or more specific polar extensions 18 may have a surface facing the side surface of the metal product 11, which has a shape cooperating with said side surface.

According to another variant, personalization is obtained in each case with specific additions to the polar extensions 18 themselves, and attention is paid to the continuity of the function.

For example, the specific additional portion may be a portion of the polar extension portion 18 that specifically conforms to the metal product 11 to be treated or the heat treatment to be performed.

According to another variant, one or more polar extensions 18 can be replaced both for maintenance reasons and for specific reasons of personalization.

With respect to the exemplary modality, fig. 3 shows the case where only one electrical coil 20 is powered, which induces an electrical current near two adjacent edges 12.

Fig. 4 shows a situation in which two adjacent electrical coils 20 are supplied with electrical currents in opposite directions to each other. In this case, the induced current allows one edge 12 to be heated with a greater intensity than the two edges 12 adjacent thereto.

Fig. 5 shows a situation in which all electrical coils 20 are supplied with current, each in the opposite direction to the current passing in its neighboring electrical coils 20. In this case, the induced current allows heating of all four edges 12.

Fig. 6 shows the case where all electrical coils 20 are powered, each with a current in the opposite direction to the current passing in one of its adjacent electrical coils 20 and in the same direction as the current passing in the other adjacent electrical coil 20. In this case, the induced current allows heating of the two opposite edges 12.

According to a possible embodiment, the polar extension 18 is selectively movable with respect to the through hole 14.

According to a possible advantageous embodiment, as shown in the example in fig. 7-11, the polar extensions 18 are selectively movable orthogonally to the through holes 14.

According to a possible embodiment, the polar extensions 18 may be moved (possibly linearly) by respective independent actuators 26, so as to adapt the distance between a particular polar extension 18 and the surface of the metal product 11.

This configuration allows optimizing the position of the polar extensions 18, thereby heating the desired edge 12 to the desired depth, while ensuring high performance of the transfer of thermal power.

In fig. 10, by way of example, a situation is shown in which it is useful and necessary that the electrical coil 20 is as close as possible to the surface on which the magnetic flow 22 has to run.

In this case, the movable polar extension 18 also has a base for the electrical coil 20.

According to these embodiments, it is possible to provide two polar extensions 18 near a specific edge 12 and to power one of the two electrical coils 20, so as to induce an electrical current only in the edge 12 intended to be heated (see fig. 11).

It is clear that modifications and/or additions may be made to the heating device 10 as described heretofore, without departing from the field and scope of the present invention.

For example, according to a possible variant, a containing body 27 can be provided in the through hole 14, which is able to contain the metal product 11 during its passage through the heating device 10.

The containing body 27 may be configured to guide the metal product along a defined path.

The containing body 27 may be made of a shielding material (screening material) which allows the lines of magnetic flow 22 to pass through, but does not dissipate the heat generated in the metal product 11.

The receiving body 27 may also serve as a physical barrier to ensure that the polar extension 18 does not come into contact with the metal product 11.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of heating device 10, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

Claims

1. Heating device for metal products (11) able to heat selectively and with a desired thermal power one or more edges (12) of the metal product (11) by electromagnetic induction, comprising a magnetic core (13) having a through hole (14) and at least four polar extensions (18) arranged at equal angles along the perimeter of the through hole (14), characterized in that the polar extensions (18) are located on the same lying plane and are connected to each other by a connecting portion (19), wherein the lying plane is defined as the plane of all upper or all lower ends of the polar extensions (18), each of the polar extensions (18) being provided with a respective electric coil (20) connected to an independent electric power source (21) able to define at least the polarity delivered by the polar extensions (18), Frequency and power.

2. The device according to claim 1, characterized in that said polar extension (18) and said connection portion (19) constitute a single body of said magnetic core.

3. The device according to claim 1, characterized in that said connection portion (19) and said polar extension (18) are two or more bodies and are structurally or functionally connected to each other to obtain a continuous magnetic flow.

4. The device according to claim 3, characterized in that said polar extension (18) is selectively movable with respect to said through hole (14).

5. The device according to claim 4, characterized in that said polar extensions (18) are selectively orthogonally movable with respect to said through holes (14) by means of respective independent actuators (26).

6. The device according to any of the claims 3 to 5, wherein the polar extension (18) is selectively replaceable.

7. The device according to claim 1, characterized in that at least one of said polar extensions (18) is conformed to the contour of said metal product (11).

8. The device according to claim 1, characterized in that the magnetic core (13) comprises one or more magnetic sections (16) between which cooling plates (17) are provided, each of the magnetic sections (16) comprising a plurality of magnetic sheets (15).

9. The device according to claim 1, characterized in that each of said electrical coils (20) comprises an electrical cable (23) connected to said source of electrical power (21) and is located inside a respective cooling tube (24) through which a cooling liquid passes.

10. A device according to claim 1, wherein each of said electrical coils (20) is replaceable.