EP0951371B1 - Method of producing a cooling plate for iron and steel-making furnaces - Google Patents

Abstract

A method for production of a cooling plate (50, 80) with integrated coolant ducts (52, 84) for iron and steel making furnaces, in particular blast furnaces, is described. A preform of the cooling plate (50, 80) is continuously cast by a continuous casting mould (10), wherein rod-shaped inserts (28) in the casting duct (20) of the continuous casting mould (10) produce in this preform ducts (52, 84) running in the continuous casting direction, which form coolant ducts in the finished cooling plate.

Description

The present invention relates to a method for producing a Cooling plate with integrated coolant channels for furnaces for iron or steel production, such as Blast furnaces, from a block of copper.

Such cooling plates for blast furnaces are also called "staves". she are arranged on the inside of the furnace shell and have internal Coolant channels connected to the cooling system of the shaft furnace become. The surface facing the inside of the furnace is mostly with lined with a refractory material.

Most of these cooling plates are still made of cast iron today manufactured. However, since copper has a much better thermal conductivity than Cast iron, it would be desirable to use copper cooling plates. So far, there have been various manufacturing processes for copper cooling plates suggested.

The first attempt was to cast copper cooling plates by molding produce, the internal coolant channels through a sand core in the Mold are formed. However, this procedure has been used in practice not proven, since the cast copper plates often voids and porosities have an extremely negative impact on the life of the panels, the molding sand is difficult to remove from the cooling channels and / or Cooling channel in the copper is poorly designed.

From GB-A-1571789 is known in the molding of the cooling plates Sand core through a preformed metallic pipe coil made of copper or Stainless steel to replace. The latter is in the mold in the cooling plate body poured in and forms a serpentine coolant channel. Also this method has not proven itself in practice. Between the Cooling plate body made of copper and the cast pipe coil namely, due to various causes, a high heat transfer resistance, so that there is a relatively poor cooling of the plate. Furthermore, voids and porosities in the copper can also occur with this method cannot be effectively prevented.

From DE-A-2907511 a cooling plate is known which consists of a forged or rolled copper block. The coolant channels are blind holes that are caused by mechanical deep drilling in the rolled copper block. With these cooling plates, the the aforementioned disadvantages of die casting avoided. In particular are Voids and porosities in the plate are practically excluded. Unfortunately they are Manufacturing costs of these cooling plates, however, relatively high, because in particular that Deep drilling the cooling channels is complicated, time consuming and expensive.

The invention is therefore based on the object of a method to propose with the particularly high quality Have copper cooling plates manufactured cheaper. This task is accomplished by a Method according to claim 1 solved.

According to the invention, a preform is formed by means of a continuous casting mold Continuous casting cooling plate, inserts in the casting channel of the continuous casting mold in Generate continuous channels in the preform that in the finished cooling plate form coolant channels. From the continuously cast Preform can then be relatively easily, without complex deep drilling, a Complete the long-length cooling plate. This is in particular It should be noted that cavities and porosities in continuous casting are far greater can be prevented more effectively than when molding. Furthermore, the mechanical strength of a continuously cast cooling plate is much higher than that of a molded cooling plate. The heat transfer is optimal because the continuously cast channels are formed directly in the cast body. Since the cross section of the continuously cast channels is not necessarily circular must be, new advantageous possibilities regarding the design and arrangement of the coolant channels opened. It was also found that the special nature of the surface of a continuous cast Cooling plate is a good basis for the adhesion of a refractory spray compound brings with it.

During continuous casting, the tines in the pouring channel can Continuous casting mold in a continuous direction grooves in one surface of the preform. These grooves enlarge the cooled surface the finished cooling plate and form anchors for a refractory Lining out. However, such grooves can also be retrofitted into one Surface of the continuously cast preform incorporated, for example be milled. This procedure is necessary, for example, if the Grooves should run transverse to the continuous casting direction.

If particularly thin cooling plates are to be produced, the thickness is the continuously cast preform is advantageously reduced by rolling. By the Rolling the crystal structure of the copper becomes finer, which is beneficial to the mechanical and thermal properties of the finished cooling plate. Although the reduction in rolling increases the manufacturing cost of the cooling plate, it can it can therefore be advantageous to use also continuously cast preforms for thicker ones Roll cooling plates. In this context it is special to emphasize that the channels cast into the preform Surprisingly, this is not a major obstacle to subsequent rolling the preform. This is especially true if the cast in Channels have an elongated, for example oval cross section.

The continuously cast and, if necessary, rolled preform is transformed into two Cut a plate across the casting direction, two End faces are formed transversely to the casting direction, the distance between them in essentially corresponds to the desired length of the cooling plate. It is It should be noted that it is advantageous to have several from a continuously cast preform Cooling plates of the same or different lengths can be produced. The Manufacturing particularly long cooling plates is also without additional effort possible. The plates separated from the preform have several parallel through channels that extend in the casting direction and in the two ends each form a junction.

The cross section of the cast channels advantageously has an elongated one Form that has its smallest dimension perpendicular to the cooling plate. Hereby cooling plates can be produced with a smaller plate thickness than Cooling plates with drilled channels, which saves copper. It is also note that channels with elongated cross sections are also easier are to be produced during continuous casting. Another advantage is that at Channels with elongated cross-sections have larger exchange surfaces on the coolant side can be achieved in the cooling plate. Channels with elongated (such as Example oval) cross sections behave as already above indicated, also much more advantageous when rolling the preform than channels with circular cross sections.

In the next manufacturing step, the Through holes opening connection holes for preliminary and Return lines drilled perpendicular to the back surface in the plate, and the frontal openings of the channels closed. In these Connection holes can then be used to connect the one from the furnace shell with a cooling plate mounted on the furnace shell be brought out.

Each continuously cast channel can have its own lead and Have return connection. Multiple continuous cast channels can however, they can also be connected to one another by means of transverse bores. This Cross bores are then arranged and closed, for example, that a serpentine channel with a flow connection and a Return connection per cooling plate results.

The cooling plate can advantageously be bent and centered in such a way that their curvature is adapted to the curvature of the furnace. This is especially the case when cooling plates with a large width are used. This is also the case for cooling plates that are used in the blast furnace frame. Such cooling plates for the frame must indeed be as close as possible to the Nestle tanks around the pressures acting on the frame lining to record.

In order to better illustrate the invention and its advantages, are different embodiments with reference to the accompanying Drawings described in more detail.

Figur 1:

einen schematischen Längsschnitt durch eine Stranggießform für das erfindungsgemäße Verfahren;

Figur 2:

einen schematischen Querschnitt entlang der Schnittlinie 2-2 durch die Stranggießform nach Figur 1;

Figur 3:

eine Draufsicht auf die Rückseite einer fertigen Kühlplatte, die mit dem erfindungsgemäßen Verfahren hergestellt wurde;

Figur 4:

einen Längsschnitt entlang der Schnittlinie 4-4 durch die Kühlplatte der Figur 3;

Figur 5:

einen Querschnitt entlang der Schnittlinie 5-5 durch die Kühlplatte der Figur 3;

Figur 6:

eine perspektivische Ansicht einer Anordnung von Kühlplatten in einem Schachtofen;

Figur 7:

eine Draufsicht auf die Rückseite einer Kühlplatte die besonders für die Anordnung nach Figur 6 geeignet ist und mit dem erfindungsgemäßen Verfahren hergestellt wurde.

Show it:

Figure 1:

a schematic longitudinal section through a continuous casting mold for the inventive method;

Figure 2:

a schematic cross section along the section line 2-2 through the continuous casting mold according to Figure 1;

Figure 3:

a plan view of the back of a finished cooling plate, which was produced with the inventive method;

Figure 4:

a longitudinal section along section line 4-4 through the cooling plate of Figure 3;

Figure 5:

a cross section along section line 5-5 through the cooling plate of Figure 3;

Figure 6:

a perspective view of an arrangement of cooling plates in a shaft furnace;

Figure 7:

a plan view of the back of a cooling plate which is particularly suitable for the arrangement of Figure 6 and was produced with the inventive method.

Figure 1 and Figure 2 show schematically the structure of a continuous casting mold 10 for the method according to the invention. This continuous casting mold 10 consists of Example of four cooled mold plates 12, 14, 16 and 18, one cooled Pour 20 for a melt, for example a low alloy Form copper melt. The arrows 22 and 24 in Figure 1 indicate Flow connections and return connections for a coolant in the side Form plates 12 and 14. The arrow 25 in Figure 1 shows the pouring direction.

In Figure 1 you can see that in the pouring channel 20 three rod-shaped inserts 28 protrude. The latter are e.g. to a coolant collector 30 connected, the above the mold plates 12-18 above the pouring channel 20 is arranged. Each of these rod-shaped inserts 28 advantageously consists of an outer tube 32 which is closed at the end and an open one at the end Inner tube 34 which are arranged such that they have an annular gap 36 for the Train coolant. For each of the three rod-shaped inserts 28 results thus the following coolant flow. the coolant overflows in the collector 30 a flow chamber 38 into the annular gap 36. It cools the outer tube 32 its entire length and emerges from the annular gap 36 in the lower end Inner tube 34 a. This inner tube 34 directs the coolant into a Return chamber 40 back in the collector 30. The rod-shaped inserts 28 can also be designed as uncooled graphite rods.

In Figure 2 it can be seen that the front mold plate 16 has a plurality of tines 26 having. The latter extend essentially over the entire length of the Molding plate 16 and protrude perpendicularly to the casting direction into the pouring channel 20 inside.

The above-described continuous casting mold 10 is used in accordance with the invention Cast strand, which forms a preform of the cooling plate to be produced. The rod-shaped inserts 28 produce in the continuous cast Preform channels running in the continuous casting direction, the cross section of which the cross section of the rod-shaped inserts 28 is determined. The tines 26 in of the mold plate 18 produce in the continuously cast preform in Longitudinal grooves running in the casting direction.

Figures 3 to 4 show a finished cooling plate 50 based on a continuously cast preform. However, it should be noted that the preform of the cooling plate 50 was cast with a continuous mold that had no tines 26 so that the original preform essentially had a rectangular cross section without grooves. In Figure 3 are with Dashed lines indicated the three channels 52 according to the invention Continuous casting through which inserts were created in the continuous casting mold. This The inserts had an oval shape, as can be seen in FIG. 5. You were in the Continuous casting mold, as can still be seen from FIGS. 4 and 5, off-center in the rectangular cross-section of the preform, i.e. they were closer to the Finally, the surface of the preform in the finished cooling plate 50 Rear forms.

It has proven advantageous to make the preform thicker than the finished one Cooling plate required to pour, and then the thickness of the preform by rolling to reduce the thickness of the finished cooling plate. At This rolling of the preform gives the copper a finer crystal structure, what positive on the mechanical and thermal properties of the finished Cooling plate affects. In this connection it remains to be stated that a from the beginning an elongated cross section of the cooling channels during rolling is deformed more advantageously than a circular cross section.

You then have two cuts from the rolled preform transversely to the casting direction, a rectangular raw plate was cut out. Hereby the two end faces 54, 56 of the finished cooling plate were formed. In This raw plate, the channels 52 thus extended as through channels between the two end faces 54, 56 and formed open here Junctions 58 out. The largest in the surface of this raw plate Grooves were then spaced from the off-center channels 52 58 milled transversely to the casting direction. To the mechanical strength of the plate to increase it even further, it could now be shot peened.

In the next manufacturing step, ducts 52 opened Connection holes 62 for flow and return ports 64, 66 perpendicular to Plate surface drilled in the back 68 of the plate. Before the front The mouths 58 of the channels 52 are definitely closed by plugs 70 If necessary, the channels could be mechanically reworked become. To finalize the cooling plate 50 only had to Flow and return spout 64, 66, and mounting spigot 72 and Spacer 74 are attached to the plate.

In Figure 5 you can see how the finished cooling plate 50 by means of Spacer 74 rests on a furnace plate 76. It stays it should be noted that the cooling plate 50 of Figures 3-5 is for a vertical one Installation in the oven, i.e. that in the built-in cooling plates Cooling ducts 52 run vertically and the transverse grooves 60 run horizontally. Instead of of the transverse grooves 60, which are transverse to the casting direction, could be the cooling plate 50 also have longitudinal grooves that run parallel to the casting direction. Latter would then be advantageous with a mold with tines, as shown in Figure 2 is shown, generated directly during continuous casting.

FIG. 6 shows an arrangement of cooling plates 80 in which the grooves 82 were produced in this way directly during continuous casting. The cooling plates 80 which are produced during the continuous casting extend Cooling channels 84 (see FIG. 7) are therefore parallel to the grooves 82. It should be noted that that the cooling plates 80 are arranged horizontally in the oven, i.e. that in the built-in cooling plates 80, the cooling channels 84 and the grooves 82 horizontally run. The cooling plates 80 are bent and centered such that their Curvature adapted to the curvature of the blast furnace shell (not shown) is.

FIG. 7 shows with dashed lines an advantageous arrangement of the coolant channels in one of the cooling plates 80. Three continuously cast channels 84 ₁ , 84 ₂ and 84 ₃ and two short transverse bores 86 and 88 can be seen. The bore 86 connects the channels 84 ₁ and 84 ₂ at one end of the plate 80 and is closed with a plug 90. The bore 88 connects the channels 84 ₂ and 84 ₃ at the other end of the plate 80 and is closed with a plug 92. Like the channels 52 in the plate 50, the channels 84 ₁ , 84 ₂ and 84 ₃ in the end faces 54, 56 of the plate 80 are also closed by plugs 70. The reference number 94 shows a flow connection which opens into the channel 84 ₁ , and the reference number 96 shows a return connection which opens into the channel 84 ₃ . The coolant that enters the plate 80 via the supply connection 94 must flow through the latter in a serpentine fashion before it can leave it again via the return connection 96. FIG. 6 shows schematically how the supply and return connections 94, 96 of the individual cooling plates 80 are connected to one another via pipe bridges 98. Of course, the cooling plate 80, like the cooling plate 50, could also have a flow and return connection for each cooling channel 84 ₁ , 84 ₂ and 84 ₃ .

It should be noted that the cooling plates in the furnace above the Blow molds are advantageously attached to the inside of the furnace facing the side with a fireproof spray compound. To the Adhesion of the refractory spray compound to the cooling plates can improve the grooves 60, 82 are designed, for example, as dovetail grooves become. It is also advantageous to have the edges and corners of the grooves 60, 82 to round off generously. This will in fact increase the risk of cracking the refractory mass is reduced.

In contrast, cooling plates for the frame of the blast furnace advantageously have one smooth front and back on. They are thinner than the cooling plates shown with grooves and are advantageous from a continuously cast preform manufactured, the thickness of which was reduced by rolling. You will be on the Diameter of the shell centered in the area of the frame, so that it Form-fit against the blast furnace shell with its smooth rear surface. The frame lining with shaped stones made of carbon lies here form-fitting on the likewise smooth front of the cooling plates. This ensures that relatively thin cooling plates can withstand the high pressures that act on the frame lining without problems on the blast furnace can transmit.

All cooling plates shown have three continuously cast channels. Of course, you can also use the method according to the invention Cooling plates with more or less than three continuously cast channels getting produced.

Claims (11)

1. Method for production of a cooling plate (50, 80) with integrated coolant ducts (52, 84) for iron and steel making furnaces from an ingot of copper, characterised in that
   the ingot of copper is continuously cast by means of a continuous casting mould (10), wherein rod-shaped inserts (28) in the casting duct (20) of the continuous casting mould (10) produce ducts (52, 84) running in the continuous casting direction, which form coolant ducts in the finished cooling plate, so that the continuously cast ingot of copper forms a preform of the cooling plate (50, 80).
2. Method according to claim 1, characterised in that the continuous casting mould (10) has prongs (26), which produce grooves (82) running in the continuous casting direction in a surface of the preform.
3. Method according to claim 1 or 2, characterised in that grooves (60) running at right angles to the continuous casting direction are worked into a surface of the continuously cast preform.
4. Method according to one of claims 1 to 3, characterised in that a plate is cut out of the preform by two cuts at right angles to the casting direction, whereby two end faces (54, 56) are formed at right angles to the casting direction, and the ducts (52, 84) extend as through ducts through the plate between the two end faces (54, 56) and form terminations (58) therein.
5. Method according to claim 4, characterised in that connection holes (62) for feed and return pipes (64, 66) terminating in the ducts (52, 84) are drilled into the plate (50, 80) at right angles to the plate surface, and the end terminations (58) of the ducts (52, 84) are closed.
6. Method according to one of claims 1 to 5, characterised in that the crosssection of the continuously cast ducts (52, 84) has an elongated shape which has its smallest dimension at right angles to the cooling plate (50, 80).
7. Method according to one of claims 1 to 6, characterised in that the continuously cast ducts (52, 84) are connected to each other by transverse holes (86, 88).
8. Method according to claim 7, characterised in that the transverse holes (86, 88) are arranged and closed in such a way that a spiral continuous duct with a feed connection (94) and a return connection (96) results.
9. Method according to one of claims 1 to 8, characterised in that the cooling plate (80) is centered in such a way that its curvature is adapted to the curvature of a shaft furnace wall.
10. Method according to one of claims 1 to 9, characterised in that the preform is continuously cast from a copper alloy.
11. Method according to one of claims 1 to 10, characterised in that the thickness of the continuously cast preform is reduced by rolling.

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