ES2399609T3 - Manufacturing procedure of a cooling plate for a metallurgical furnace - Google Patents

Abstract

Method of manufacturing a cooling plate for a metallurgical furnace, said method comprising the following steps: providing a plate of metallic material, said plate having a front face, an opposite rear face and four lateral edges; and providing said plate with at least one cooling channel by drilling at least one blind hole inside said plate, said blind hole being drilled from a first edge towards an opposite second edge; characterized in that it comprises the following steps: deforming said plate, in such a way that a first edge zone of said plate is at least partially bent towards said rear face of said plate; and machining excess material from said front and rear faces of said plate to produce a cooling plate having a panel-shaped body, wherein a first opening in said cooling channel is located in said rear face; providing said cooling channel with a second opening located on said rear face.

Description

Manufacturing procedure of a cooling plate for a metallurgical furnace.

Technical field

The present invention relates, in general, to a method of manufacturing a cooling plate for a metallurgical furnace.

Prior art

Refrigeration plates of this type for a metallurgical furnace, also called panels, are known in the art. They are used to cover the inner wall of the outer casing of the metallurgical furnace, such as a blast furnace or an electric arc furnace, to provide: (1) a heat evacuation shield between the furnace interior and the casing oven outside; and (2) anchoring means for a lining of refractory bricks, a refractory gunite or a layer generated by an accumulation process inside the oven. Originally, the cooling plates have been cast iron plates with molded cooling pipes inside. As an alternative to cast iron panels, copper panels have been developed. Currently, most of the cooling plates for a metallurgical furnace are made of copper, a copper alloy or, more recently, steel.

Different manufacturing procedures have been proposed for copper panel refrigerators. Initially, an attempt was made to make copper panels by casting in molds, the inner channels of the refrigerant being formed by a sand core in the foundry mold. However, this procedure has not proven effective in practice, because the bodies of the molten copper plates often have cavities and porosities, which have an extremely negative effect on the life of the plate bodies. The sand mold is difficult to extract from the channels and the channels are often not formed properly.

A cooling plate made from a forged or rolled copper plate is known from DE 2 907 511 C2. The coolant channels are blind drills introduced by deep drilling of the laminated copper plate. Blind holes are sealed tightly by welded plugs. Then, the connection holes are drilled from the rear side of the plate body inside the blind holes. After that, the ends of the connection pipes for the refrigerant supply or the return of the refrigerant are inserted inside these connection holes and welded to the panel body. With these cooling plates, the aforementioned disadvantages related to casting are avoided. In particular, cavities and porosities in the plate body are virtually prevented. The previous manufacturing process however is relatively expensive in both labor and material. Additionally, due to the considerable mechanical and thermal stresses to which the panel cooler is exposed, the different welded connection joints are critical with respect to fluid tightness. In addition, since the channels form a single piece with the panel body, there is only one level of separation between the refrigerant and the interior of the oven, that is, if the panel body opens slightly, the refrigerant will leak. A leak of refrigerant fluid inside the oven however leads to a significant risk of explosion and should therefore be avoided at any cost.

Technical problem

An object of the present invention is to provide an improved method of manufacturing a cooling plate for a metallurgical furnace, in which the process does not have the aforementioned disadvantages. This object is achieved by a method as claimed in claim 1.

General Description of the Invention

A process for the manufacture of a cooling plate for a metallurgical furnace according to the present invention comprises the steps of providing a plate of metallic material, the plate being provided with a front face, an opposite rear face and four side edges; and providing the plate with at least one cooling channel by drilling at least one blind hole inside the plate, in which the blind hole is drilled from a first edge to a second opposite edge. According to an important aspect of the present invention, the method comprises the additional steps of the deformation of the plate such that the first edge area of the plate is at least partially folded towards the rear face of the plate and the mechanization of the excess material of the front and rear faces of the plate to produce a cooling plate provided with a panel-shaped body in which a hole towards the cooling channel is placed in the rear face.

By folding the plate towards the rear face and consequent machining of the excess material from the front and rear faces of the plate, the hole towards the cooling channel is placed on the rear face. Compared to the prior art procedure, as described in DE 2 907 for example

511 C2, it is no longer necessary to hermetically close the hole to the cooling channel at the first edge by welding a plug. It is also not necessary to drill a connection hole between the rear face and the cooling channel to access the cooling channel in the first edge area. The elimination of these stages of the process reduces the costs of both labor and material.

More important, however, the absence of the plug provides a more dependent cooling plate. Of course, since the cooling plate is exposed to considerable mechanical and thermal stresses, particularly in the areas of the edges of the cooling plate, the plug has to be considered as a weak point. If the welding of the plug deteriorates, the fluid tightness of the cooling channel is no longer guaranteed and the refrigerant can escape from the cooling channel into the oven. A leak of this type of refrigerant fluid inside the furnace must, however, be avoided at any cost as it can lead to a significant risk of explosion. Since there is no plug welded to the cooling plate manufactured according to the method of the present invention, the risk of a leakage occurring through such a plug is avoided. Additionally, the cooling plate manufactured according to the process of the present invention also has a thickness of the most important material on the front face in the first edge area, compared to the cooling plates manufactured according to the prior art procedures. The increased thickness of the material also contributes to a longer shelf life of the cooling plate.

Preferably, after machining the material in excess of the front and rear faces of the plate, the method comprises the additional stage of the formation of intermittent lamellar grooves and ribs on the front face the panel-shaped body for anchoring a coating of refractory bricks.

To ensure a good anchoring function of the laminar ribs and the structure of the grooves on the front face of the cooling plate and a good thermal stability of the shape of the cooling plate, the grooves are advantageously formed with a width which is narrower at the entrance of the slot than at a base of the slot. The grooves for example can be formed with a cross section in dovetail.

Preferably, the method comprises the additional step of providing a connecting pipe for each cooling channel formed in the panel-shaped body; the alignment of one end of each connecting pipe with an opening in the respective cooling channel disposed on the rear face of the panel-shaped body and the connection of the connection pipes to the rear face of the body in the form of a panel so that a fluid connection be created between each connection pipe and its associated cooling channel.

An adapter can be arranged between the panel-shaped body and the connecting pipe, the adapter having the shape of a hollow truncated cone. The smaller base of the adapter may have a diameter adapted for connection to the connecting pipe. The main base of the adapter is sized so that it covers the entire opening of the cooling channel in the rear face. Of course, due to the bending of the cooling channel and the subsequent machining of the rear face, the cooling channel may have an elongated opening in the rear face. The larger base of the adapter ensures that a leak in the rear face of the cooling plate can be avoided.

Preferably, the rear face of the panel-shaped body, the connecting pipe and, if applicable, the adapter are connected together through welding with material input and lead or welding.

According to a first embodiment of the invention, the method comprises the steps of providing the plate with a first cooling channel by drilling a first blind hole inside the plate, in which the first blind hole is drilled from the first edge towards the second edge and provide the plate in a second cooling channel by drilling a second blind hole inside the plate, in which the second blind hole is drilled from the first edge to the second edge . The first and second cooling channels are arranged such that their ends in a second edge zone meet and form a fluid communication between the first and second cooling channels.

The first and second blind holes are both drilled from the first edge to the second edge at an angle to each other, so that their ends meet in the second edge zone. The resulting first and second cooling channels thereby form a "V" shaped cooling channel, in which the refrigerant flows through one of the cooling channels to the second edge zone and then, through the another of the cooling channels, back to the area of the first edge. Such a "V" shaped cooling channel allows both the inlet connection pipe and the outlet connection pipe to be arranged in the first edge zone.

According to a second embodiment of the invention, the method comprises the steps of providing the plate with a first cooling channel by drilling a first blind hole inside the plate, in which the first blind hole is drilled from the first edge towards the second edge and provide the plate with a second cooling channel by drilling a second blind hole inside the plate, in which the second blind hole is drilled from the second edge to the first edge. The channels of

First and second cooling are arranged such that their ends meet and form a fluidic communication between the first and second cooling channels.

The first and second blind holes are drilled from opposite edges to a central area of the plate, such that their ends are in the central area. The resulting first and second cooling channels thereby form a combined cooling channel that extends from the first edge to the second edge. This is of particular importance when a cooling plate with a particularly important height has to be manufactured. Of course, blind holes can only be drilled to a particular depth. If the cooling channel has to exceed this depth, a second blind hole is usually drilled from the opposite side. In this embodiment, both the first edge zone and the second edge zone are bent towards the rear face before extracting excess material from the plate. Two openings of the cooling channel are thus formed in the rear face without resorting to the need to provide plugs at each end of the cooling channel.

According to a third embodiment of the invention, the method comprises the steps of providing the plate with a first cooling channel by drilling a first blind hole inside the plate, in which the first blind hole is drilled from the first edge towards the second edge, in which one end of the first blind hole is disposed in a second edge area of the plate and in the second edge area, the drilling of a connection hole extending from the rear face from the plate to the end of the first blind hole and forming a fluidic communication between the first cooling channel and the connection hole.

In the first edge zone, the plate is bent towards the rear face and an opening in the cooling channel is thus formed in the rear face. In the second edge zone, on the other hand, a connection hole is provided for the formation of a second opening in the cooling channel. The formation of this second opening in the cooling channel essentially corresponds to the procedure used in the prior art procedures. This embodiment is adapted for the connection of an inlet connection pipe in the first edge zone and an outlet connection pipe in the second edge zone.

Preferably, the cooling plate is made of at least one of the following materials: copper, a copper alloy or steel.

Brief description of the drawings

Preferred embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a schematic cross section through a plate according to a first stage of the process for manufacturing a cooling plate according to the present invention;

Figure 2 is a schematic cross section through a plate according to a second stage;

Figure 3 is a schematic cross section through a plate according to a third stage; Y

Figure 4 is a schematic cross section through a plate according to a fourth stage.

Description of preferred embodiments

The cooling plates are used to cover the inner wall of an outer casing of a metallurgical furnace, such as a blast furnace or an electric arc furnace. The purpose of such cooling plates is to form: (1) a heat evacuation protection screen between the inside of the oven and the outer shell of the oven; and (2) anchoring means for a lining of refractory bricks, a refractory gunite or a layer generated by an accumulation process inside the oven.

With reference now to the figures, it will be noted that the cooling plate 10 is formed from a plate 11, for example, manufactured from a cast or forged copper body, a copper or steel alloy in a body in panel shape 12. This panel-shaped body 12, which is described more carefully by reference to Figure 4, has a front face 14, also referred to as a hot face, which will face the inside of the oven and a face rear 16, also referred to as a cold face, which will face the inner surface of the oven wall. With reference to Figure 4, the panel-shaped body 12 generally has the shape of a quadrilateral with a pair of long edges (not shown) and a pair of first and second short edges 22, 24. The most modern cooling plates they have a width in the range of 600 to 1300 mm and a height in the range of 1000 to 4200 mm. However, it will be understood that the height and width of the cooling plate can be adapted, among other things, to the structural conditions of a metallurgical furnace and the limitations that result from its manufacturing process.

The cooling plate 10 additionally comprises connecting pipes 26, 28 for a cooling fluid,

generally water These connecting pipes 26, 28 are connected from the rear side of the panel-shaped body 12 to the cooling channels 30 arranged inside the body in the form of panel 12. As seen in Figure 4, these cooling channels 30 extend through the panel-shaped body 12 in the vicinity of the rear face 16. According to the proposed manufacturing process, which will be described in further detail later in this document, cooling channels 30 of this type are formed by drilling. Each cooling channel 30 is normally provided with an appropriate inlet connection pipe 26, through which the cooling fluid is fed into the cooling channel 30, or an outlet connecting pipe 28, through the which cooling fluid leaves the cooling channel 30.

With further reference to Figure 4, it will be noted that the front face 14 is subdivided by means of grooves 32 into laminar ribs 34. The grooves 32, which laterally delimit the laminar ribs 34, may be milled on the front face 14 of the body in panel shape 12. The laminar ribs 34 extend parallel to the first and second edges 22, 24 from a first long edge (not shown) to a second long edge (not shown) of the panel-shaped body 12. They are perpendicular to the cooling channels 30 in the panel-shaped body 12. When the cooling plate 10 is mounted in the oven, the grooves 32 and the laminar ribs 34 are arranged horizontally. They form anchoring means for anchoring a lining of refractory bricks, a refractory gunite or a layer generated by an accumulation process on the front face 14.

In order to guarantee an excellent anchorage for a lining of refractory bricks, a refractory gunite or a layer generated by an accumulation process on the front face 14, it should be noted that the grooves 32 have a cross section in the shape of a dovetail, this is the entrance width of a slot 32 is narrower than the width at its base. The average width of a laminar rib 34 is preferably smaller than the average width of a groove 32. Typical values for the average width of a groove 32 are for example in the range of 40 mm to 100 mm. Typical values for the average width of a laminar nerve 34 are for example in the range of 20 mm to 40 mm. The height of the laminar ribs 34 (which corresponds to the depth of the grooves 32) generally represents between 20% and 40% of the total thickness of the panel-shaped body 12.

The manufacturing process of the cooling plates 10 will now be carefully described by reference to Figures 1 to 4, which represent the cooling plates 10 at different key stages of the manufacturing process. In a first stage, shown in Figure 1, a plate 11 is provided, for example, made of a cast or forged body of copper, a copper or steel alloy. Such a plate has a globally quadrilateral shape with a front face 14, a rear face 16, a pair of long edges (not shown) and a couple of second short first and second edges 22, 24. It should be noted that the plate 11 has dimensions that exceed the desired dimensions of the panel-shaped body 12. At least one blind hole 40 is drilled from the first edge 22 inside the plate 11 and extends to a second edge area 42. The blind hole 40 has an end 44 arranged in the second edge area 42. In a subsequent stage of the process, illustrated by Figure 2, the plate 11 is deformed such that a first edge area 46 is bent towards the face. rear 16 of the plate 11. This results in a corresponding bending of the blind hole 40. The bending angle a between a central axis 50 of the unfolded blind hole 40 and a central axis 52 of the blind hole 40 on the first edge 22 may be between 30 and 45 degrees. This bending angle a for example can vary considerably depending on the thickness of the plate 11 or the diameter of the blind hole 40.

After the plate 11 is deformed, the excess material is extracted from the plate 11 along the cutting lines indicated by dashed lines 55 in Figure 2. The resulting panel-shaped body 12, shown in the Figure 3, is again of a globally quadrilateral shape with a front face 14, a rear face 16, a pair of long edges (not shown) and a pair of first and second short edges 22, 24. A cooling channel 30 , formed by the blind hole 40, is formed in the panel-shaped body 12 globally parallel to the rear face 16. In the first edge zone 46, the cooling channel 30 bends and opens to the inside of the rear face 16.

According to an embodiment of the present invention, the panel-shaped body 12 may be provided with a bore 60 in the second edge area 42, which extends from the cooling channel 30 to the rear face

16.

After machining the excess material of the plate 11, the resulting panel-shaped body 12 is further subjected to a milling stage, where grooves 32 and intermittent laminar ribs 34 are formed on the front face 14 of the body in the form of panel 12. As explained earlier in this document, these grooves 32 and ribs 34 form anchoring means for anchoring a lining of refractory bricks, a refractory gunite or a layer generated by an accumulation process in the front face 14 of the cooling plate 10.

Finally, the connection pipes 26, 28 are connected to the rear face 16 of the panel-shaped body 12. An inlet connection pipe 26 is fluidly connected to the opening of the cooling channel 30 in the first edge zone 46 for feeding cooling fluid inside the cooling channel 30.

A connecting pipe 28 is fluidly connected to the bore 60 in the second edge zone 42 for the evacuation of the cooling fluid from the cooling channel 30.

List of reference numbers:

5 10 cooling plate 11 plate 12 panel-shaped body 14 front face

10 16 rear face 22 first edge 24 second edge 26 inlet connection pipe 28 outlet connection pipe

15 30 cooling channel 32 groove 34 rib 40 blind hole 42 second edge zone

20 44 end 46 first edge zone a Bending angle 50 central axis of the blind hole without bending 52 central axis of the blind hole in the first edge

25 55 cutting line 60 drill

Claims (11)

1. Method of manufacturing a cooling plate for a metallurgical furnace, said process comprising the following steps: providing a plate of metallic material, said plate having a front face, an opposite rear face and four side edges; Y providing said plate with at least one cooling channel by drilling at least one blind hole inside said plate, said blind hole being drilled from a first edge to a second opposite edge; characterized in that it comprises the following stages: deforming said plate, such that a first edge zone of said plate is at least partially bent towards said rear face of said plate; Y machining the excess material of said front and rear faces of said plate to produce a cooling plate provided with a panel-shaped body, in which a first opening in said cooling channel is located in said rear face; providing said cooling channel with a second opening located on said rear face.

2.

 Method according to claim 1, wherein after machining the excess material of said front and rear faces of said plate, the method comprises the following additional step: forming intermittent laminar grooves and ribs on said front face of said body in form of panel for anchoring a lining of refractory bricks.

3.

 A method according to claim 2, wherein the grooves are formed with a width that is narrower in a groove inlet than in a groove base.

Four.

 Method according to claim 3, wherein the grooves are formed with a cross section in dovetail.

5.

 Method according to any one of claims 1 to 4, wherein the method comprises the following additional step:

providing a connecting pipe for each cooling channel formed in said panel-shaped body; align one end of each connecting pipe with an opening in the respective cooling channel disposed on the rear face of the panel-shaped body; Y connecting said connection pipes with said rear face of said panel-shaped body, so that a fluid connection is created between each connection pipe and its associated cooling channel.

6.

 Method according to claim 5, wherein an adapter is disposed between said panel-shaped body and said connecting pipe, said adapter having the shape of a hollow truncated cone.

7.

 Method according to any of claims 5 to 6, wherein said rear face of said panel-shaped body, said connecting pipe and, if applicable, said adapter are connected together by welding with material or welding.

8.

 Method according to any one of claims 1 to 7, comprising the following steps:

providing said plate with a first cooling channel by drilling a first blind hole inside said plate, wherein said first blind hole is drilled from said first edge to said second edge; providing said plate with a second cooling channel by drilling a second blind hole inside said plate, wherein said second blind hole is drilled from said first edge to said second edge; wherein said first and second cooling channels are arranged such that their ends in a second edge zone meet and form a fluidic communication between said first and second cooling channels. 9. Method according to any one of claims 1 to 7, comprising the following steps: providing said plate with a first cooling channel by drilling a first blind hole inside said plate, wherein said first blind hole is drilled from said first edge to said second edge; 5 providing said plate with a second cooling channel by drilling a second blind hole inside said plate, wherein said second blind hole is drilled from said second edge to said first edge; 10 wherein said first and second cooling channels are arranged such that their ends meet and form a fluidic communication between said first and second cooling channels. 10. Method according to any of claims 1 to 7, comprising the following steps: 15 providing said plate with a first cooling channel by drilling a first blind hole inside said plate, wherein said first blind hole is drilled from said first edge to said second edge, in which one end of said first blind hole is disposed in a second edge area of said plate; 20 in said second edge zone, drilling a connection hole extending from said rear face of said plate to said first blind hole end and forming a fluid communication between said first cooling channel and said connection hole. A method according to any of the preceding claims, wherein said cooling plate is manufactured from at least one of the following materials: copper, a copper alloy or steel.